In the personal computeroperating systemsMS-DOS and PC DOS,
a number of standard system commands were provided for common tasks
such as listing files on a disk or moving files. Some commands were
built-in to the command interpreter, others existed as transient
commands loaded into memory when required. Over the several generations
of MS-DOS, commands were added for the additional functions of the
operating system. In the current Microsoft Windows
operating system a text-mode command prompt window can still be used.
Some DOS commands carry out functions equivalent to those in a UNIX system but always with differences in details of the function.
Resident and transient commands
The command interpreter for MS-DOS runs when no application programs
are running. When an application exits, if the command interpreter in
memory was overwritten, MS-DOS will re-load it from disk. The command
interpreter is usually stored in a file called "COMMAND.COM". Some
commands are internal and built-into COMMAND.COM, others are stored on
disk in the same way as application programs. When the user types a line
of text at the operating system command prompt, COMMAND.COM will parse
the line, and attempt to match a command name to a built-in command or
to the name of an executable program file or batch file on disk. If no match is found, an error message is printed and the command prompt is refreshed.[1]
Resident commands varied slightly between revisions of MS-DOS.
Typically, the functions DIR (list directory), ERASE or DEL (erase a
file or directory), COPY (copy files), DATE (display or set date), TIME
(display or set time), CD (change working directory), MD (make a
directory on the current disk), REN (rename a file or directory) and
some others were resident in COMMAND.COM.
Transient commands were too large to keep in the command processor,
or were less frequently used. Such utility programs would be stored on
disk and loaded just like regular application programs, but were
distributed with the operating system. Copies of these utility command
programs had to be on an accessible disk, either on the current
logged-in floppy drive or on the command path set in the command interpreter.
A special type of external, transient command is the batch file,
containing a set of commands that are processed as if entered at the
command line. Some additional keywords are recognized by the command
interpreter COMMAND.COM to make batch files more useful. These commands
aren't useful if typed in interactively at the command prompt, but allow
flexible processing by a batch file.
The Windows™ 95/98 Network Programs
Mostly Command-Line Programs for
Intranets and the Internet
Note: Microsoft ported most of
these programs directly from Windows NT 4.0 or even NT 3.5
Sometimes people think of these programs as
MS-DOS commands, but they have nothing to do with the Disk Operating System!
They are simply Command-Line (or Window's Console) programs which were
included with the Windows 95/98 OSs. They are all full 32-bit
programs which means they cannot be exectued until after Windows (a 32-bit
operating system) is up and running. These programs are found in your
WINDOWS directory.
-e Displays Ethernet statistics. This may be combined with the -s option.
-n Displays addresses and port numbers in numerical form.
-p proto Shows connections for the protocol specified by proto; proto may be TCP or UDP. If used with the -s option to display per-protocol statistics, proto may be TCP, UDP, or IP.
-r Displays the routing table.
-s Displays per-protocol statistics. By default, statistics are shown for TCP, UDP and IP; the -p option may be used to specify a subset of the default.
interval Redisplays selected statistics, pausing interval seconds between each display. Press CTRL+C to stop redisplaying statistics. If omitted, netstat will print the current configuration information once.
First, I would recommend that you always use the '-a' parameter so you can
see UDP 'listening ports' as well (often
used by trojans), and not just the active TCP connections; then switch
between using the '-a' and no parameters at all, to see the differences.
When you're offline, you normally shouldn't see any connection data!
If you do see an OPEN PORT NUMBER 'listening' for a connection (using
the '-a' parameter), it may be that your computer has been infected with
a trojan! Click this link for a few more ideas on how you can
check to see if your computer is Trojan
Free?
If you're running a server, such as the free XITAMI server, you
might see something like this ("My_Comp" is the name of my
computer):
C:\WINDOWS>netstat -a
Active Connections
Proto Local Address Foreign Address State TCP My_Comp:ftp localhost:0 LISTENING TCP My_Comp:80 localhost:0 LISTENING
Or with the "-an" parameters:
C:\WINDOWS>netstat -an
Active Connections
Proto Local Address Foreign Address State TCP 0.0.0.0:21 0.0.0.0:0 LISTENING TCP 0.0.0.0:80 0.0.0.0:0 LISTENING
By simply opening a browser connection to both the HTTP (port 80) and FTP
(port 21) servers (while still offline!), I saw the following:
This may be a bit confusing to some people, but remember I'm running BOTH
the servers and clients on the same machine in these examples. A little
later (using both 'a' and 'n') I got this:
Options: -t Ping the specifed host until interrupted. -a Resolve addresses to hostnames. -n count Number of echo requests to send. -l size Send buffer size. -f Set "Don't Fragment" flag in packet. -i TTL Time To Live. -v TOS Type Of Service. -r count Record route for count hops. -s count Timestamp for count hops. -j host-list Loose source route along host-list. -k host-list Strict source route along host-list. -w timeout Timeout in milliseconds to wait for each reply.
There's one special IP number everyone
should know about:
127.0.0.1 - localhost (or loopback).
This is used to connect ( through a browser, for example) to a Web server
on your own computer. (127 being reserved for this purpose.) You can use
this IP number at all times. It doesn't matter if you're connected
to the Internet or not.
It's also called the loopback address because you can ping it
and get returns even when you're offline (not
connected to any network). If you don't get any valid replies, then
there's a problem with the computer's Network settings. Here's a typical
response to the 'ping' command:
Here's another recent example using the name of my computer which I have
tied to the IP number 127.0.0.1 in my C:\WINDOWS\HOSTS file:
C:\WINDOWS>ping My_Comp
Pinging My_Comp [127.0.0.1] with 32 bytes of data:
Reply from 127.0.0.1: bytes=32 time=1ms TTL=128 Reply from 127.0.0.1: bytes=32 time=1ms TTL=128 Reply from 127.0.0.1: bytes=32 time<10ms TTL=128 Reply from 127.0.0.1: bytes=32 time=1ms TTL=128
Ping statistics for 127.0.0.1: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 1ms, Average = 0ms
Options: -d Do not resolve addresses to hostnames. -h maximum_hops Maximum number of hops to search for target. -j host-list Loose source route along host-list. -w timeout Wait timeout milliseconds for each reply.
Here's an example which traces the route from some
ISP in Los Angeles to the main server at UCLA in California ( note how two
computers relatively close to each other may be routed way round about! ):
C:\WINDOWS>tracert www.ucla.edu
Tracing route to www.ucla.edu [169.232.33.129] over a maximum of 30 hops:
1 141 ms 132 ms 140 ms wla-ca-pm6.icg.net [165.236.29.85] 2 134 ms 131 ms 139 ms whv-ca-gw1.icg.net [165.236.29.65] 3 157 ms 132 ms 143 ms f3-1-0.lai-ca-gw1.icg.net [165.236.24.89] 4 194 ms 193 ms 188 ms a0-0-0-1.dai-tx-gw1.icg.net [163.179.235.61] 5 300 ms 211 ms 214 ms a1-1-0-1.ati-ga-gw1.icg.net [163.179.235.186] 6 236 ms 237 ms 247 ms a5-0-0-1.was-dc-gw1.icg.net [163.179.235.129] 7 258 ms 236 ms 244 ms 163.179.243.205 8 231 ms 233 ms 230 ms wdc-brdr-03.inet.qwest.net [205.171.4.153] 9 240 ms 230 ms 236 ms wdc-core-03.inet.qwest.net [205.171.24.69] 10 262 ms 264 ms 263 ms hou-core-01.inet.qwest.net [205.171.5.187] 11 281 ms 263 ms 259 ms hou-core-03.inet.qwest.net [205.171.23.9] 12 272 ms 229 ms 222 ms lax-core-02.inet.qwest.net [205.171.5.163] 13 230 ms 217 ms 230 ms lax-edge-07.inet.qwest.net [205.171.19.58] 14 228 ms 219 ms 220 ms 63-145-160-42.cust.qwest.net [63.145.160.42] 15 218 ms 222 ms 218 ms ISI-7507--ISI.POS.calren2.net [198.32.248.21] 16 232 ms 222 ms 214 ms UCLA--ISI.POS.calren2.net [198.32.248.30] 17 234 ms 226 ms 226 ms cbn5-gsr.calren2.ucla.edu [169.232.1.18] 18 245 ms 227 ms 235 ms www.ucla.edu [169.232.33.129]
Trace complete.
Note: Unless you're running a network, the following commands won't
be of much use to you...
Furthermore, if you're
concerned about Security, my advice is to NEVER use NetBios on a computer
that connects to the Internet.
NBTSTAT.exe Net Bios Stats
Displays protocol statistics and current TCP/IP connections using NBT (NetBIOS over TCP/IP).
-a (adapter status) Lists the remote machine's name table given its name. -A (Adapter status) Lists the remote machine's name table given its IP address.
-c (cache) Lists the remote name cache including the IP addresses.
-n (names) Lists local NetBIOS names.
-r (resolved) Lists names resolved by broadcast and via WINS
-R (Reload) Purges and reloads the remote cache name table
-S (Sessions) Lists sessions table with the destination IP addresses.
-s (sessions) Lists sessions table converting destination IP addresses to host names via the hosts file.
RemoteName Remote host machine name. IP address Dotted decimal representation of the IP address.
interval Redisplays selected statistics, pausing interval seconds between each display. Press Ctrl+C to stop redisplaying statistics.
-f Clears the routing tables of all gateway entries. If this is used in conjunction with one of the commands, the tables are cleared prior to running the command.
command Specifies one of four commands
PRINT Prints a route ADD Adds a route DELETE Deletes a route CHANGE Modifies an existing route
destination Specifies the host to send command.
MASK If the MASK keyword is present, the next parameter is interpreted as the netmask parameter.
netmask If provided, specifies a sub-net mask value to be associated with this route entry. If not specified, if defaults to 255.255.255.255.
gateway Specifies gateway.
All symbolic names used for destination or gateway are looked up in the network and host name database files NETWORKS and HOSTS, respectively. If the command is print or delete, wildcards may be used for the destination and gateway, or the gateway argument may be omitted.
-a Displays current ARP entries by interrogating the current protocol data. If inet_addr is specified, the IP and Physical addresses for only the specified computer are displayed. If more than one network interface uses ARP, entries for each ARP table are displayed. -g (Same as -a)
inet_addr Specifies an internet address.
-N if_addr Displays the ARP entries for the network interface specified by if_addr.
-d Deletes the host specified by inet_addr.
-s Adds the host and associates the Internet address inet_addr with the Physical address eth_addr. The Physical address is given as 6 hexadecimal bytes separated by hyphens. The entry is permanent.
eth_addr Specifies a physical address.
if_addr If present, this specifies the Internet address of the interface whose address translation table should be modified. If not present, the first applicable interface will be used.
Short for Microsoft Disk operating system, MS-DOS is a non-graphical command lineoperating system created for IBM compatible computers that was first introduced by Microsoft in August 1981 and was last updated in 1994 when MS-DOS 6.22 was released. Although the MS-DOS operating system is not commonly used today, the command shell used through Microsoft Windows is. Continue reading >>
Batch
files allow MS-DOS and Microsoft Windows users to create a lists of
commands to run in sequence once the batch file has been executed.
For example, a batch file could be used to run frequently run commands,
deleting a series of files, moving files, etc. A simple batch file does
not require any special programming skills and can be done by users who
have a basic understanding of MS-DOS commands.
A good example of a batch file for someone who is more familiar with Windows or the MacOS is to think of a batch file as a shortcut
in Windows or an icon on the MacOS. Much like a shortcut, batch files
could be used to run one or more commands or programs through the command line.
Another example of a very well known batch file is the autoexec.bat,
which is a simple boot file loaded each time the computer is loaded on
MS-DOS and early Windows computers. This batch file contained all the
necessary commands and programs used to run MS-DOS and Windows each time
the computer booted.
To create a basic batch file in MS-DOS, follow the below steps that give you an example of how to create a basic batch file.
Open an MS-DOS command window or get to MS-DOS. Additional information about doing this can be found on document CHDOS.
At the MS-DOS prompt, type: edit test.bat and press enter.
If typed properly, you should now be in a blue screen. Within the screen, type:
pause dir c:\windows dir c:\windows\system
Once
the above three lines have been typed in, click File and choose exit;
when prompted to save, click "Yes." Users who do not have a mouse cursor
can accomplish this same task by pressing ALT+F to access the file
menu, then pressing "X" to exit, and pressing enter to save changes.
Once you are back at the MS-DOS prompt, type: test
and press enter. This will execute the test.bat file and begin running
the file. Because the first line is pause, you will first be prompted to
press a key. Once you press a key the batch file will run line-by-line;
in this case, listing the files in the windows and windows\system
directories.
If you wish to add more lines to this batch file you would type "edit test.bat" to edit the file again.
Additional information about the MS-DOS edit command
can be found on our edit command page. Some versions of MS-DOS and
bootable diskettes may not have the edit command; if this is the case,
you would either need to obtain the edit.com file to access this file or
use the copy con command.
Microsoft Windows and other users
A
Windows user can still use the above MS-DOS steps if they wish to
create a batch file. If, however, you're more comfortable using
Microsoft Windows or your operating system, you can use any text editor,
such as Notepad or Wordpad, to create your batch files, as long as the file extension ends with .bat. In the below example we use the Windows notepad to create a batch file.
Once notepad is open, type the below lines in the file or copy and paste the below lines into notepad.
@echo off echo Hello this is a test batch file pause dir c:\windows
Click
File and click Save; browse to where you want to save the file. For the
file name, type "test.bat", and if your version of Windows has a "Save
as type" option, choose "All files", otherwise it will save as a text
file. Once all of this has been done click the Save button and exit
notepad.
Now, to run the batch file, double-click or run the
file like any other program. Once the batch file has completed running
it will close the window automatically.
Batch commands
Just like all MS-DOS commands, all batch file commands are not case sensitive. However, in the below listing we have listed all commands in all caps to help you identify what is a command and what is not.
@
Does not echo back the text after the at symbol. This is most commonly used as @ECHO OFF to prevent any of the commands in the batch file from being displayed, just the information needed.
%1
The
percent followed by a numeric value, beginning with one, allows users
to add variables within a batch file. The below line is an example of
what can be used in a batch file.
ECHO Hello %1
When the
above one-line batch file is created, add your name after the batch
file. For example, typing myname (being the name of the bat file) and
then your name:
myname bob
would output:
Hello bob
Note: This can be extended to %2, %3, and so on.
::
One of two ways of adding remarks into the batch file without displaying or executing that line when the batch file is run.
:LABEL
By adding a colon in front of a word, such as LABEL, you create a category, more commonly known as a label. This allows you to skip to certain sections of a batch file such as the end of the batch file. Also see GOTO.
CALL
This
is used to run another batch file within a batch file. When the batch
file that is called is completed, the remainder of the original batch
file is completed. Note if the batch file does not exist it will give an
error message.
Additional information and the syntax of this command in each version of Windows and MS-DOS can be found on our CHOICE command page.
CLS
Just like the DOS command would clear your screen.
Additional information and the syntax of this command in each version of Windows and MS-DOS can be found on our CLS command page.
ECHO
Will echo a message in the batch file. Such as ECHO Hello World will print Hello World on the screen when executed. However, without @ECHO OFF
at the beginning of the batch file you'll also get "ECHO Hello World"
and "Hello World." Finally, if you'd just like to create a blank line,
type ECHO. adding the period at the end creates an empty line.
EXIT
Exits out of the DOS window if the batch file is running from Windows.
Additional information and the syntax of this command in each version of Windows and MS-DOS can be found on our EXIT command page.
GOTO LABEL
Used to go to a certain label, such as LABEL. An example of GOTO would be to GOTO END. For an example of this see running different programs.
Additional information and the syntax of this command in each version of Windows and MS-DOS can be found on our GOTO command page.
IF
Used
to check for a certain condition if the condition exists. If that
condition exists it will perform that function. To see an example of
this see running different programs.
Additional information and the syntax of this command in each version of Windows and MS-DOS can be found on our IF command page.
PAUSE
Prompt the user to press any key to continue.
REM
One of two ways of adding remarks into the batch file without displaying or executing that line when the batch file is run.
SHIFT
Changes the position of replaceable parameters in a batch program.
Used for Windows 95, Windows 98, and Windows NT 4.0 and above to start a windows application; such as START C:\WINDOW\CALC would run the Windows Calculator. Users running Windows 3.x need to utilize the WIN command. For example, WIN C:\Windows\CALC.EXE would run Windows and then Calculator after Windows has finished loading.
Below
is a simple example of how you can implement the choice options into
your batch files. Each line that is in red can be left out of the batch
file. They have been included to help explain some of what the batch
file means. Windows 2000 and Windows XP
users will need to substitute the choice command with the set command; see
the set command page for additional help and information with this command.
@ECHO OFF REM - LABEL INDICATING THE BEGINNING OF THE DOCUMENT. :BEGIN CLS REM - THE BELOW LINE GIVES THE USER 3 CHOICES (DEFINED AFTER /C:) CHOICE /N /C:123 PICK A NUMBER (1, 2, or 3)%1 REM - THE NEXT THREE LINES ARE DIRECTING USER DEPENDING UPON INPUT IF ERRORLEVEL ==3 GOTO THREE IF ERRORLEVEL ==2 GOTO TWO IF ERRORLEVEL ==1 GOTO ONE GOTO END :THREE ECHO YOU HAVE PRESSED THREE GOTO END :TWO ECHO YOU HAVE PRESSED TWO GOTO END :ONE ECHO YOU HAVE PRESSED ONE :END
How to start Windows files and other programs from a batch file
To run Microsoft Windows programs or files use the START command. The below example would run Windows Notepad.
START /MAX NOTEPAD
You can also specify the direct location of the file by typing the below command.
START /MAX C:\Windows\NOTEPAD.EXE
*Windows
users who have a different directory (e.g. Windows 2000 users) would
need to substitute WINNT or the name of their directory in place of
Windows in the above example.
The /m representing it to start the window Maximized. See the
start command page for additional information about this command.
Creating a batch file delay
Below
is an example of how to delay a batch file any where from 5 to 99
seconds. In the below example we illustrate a 5 second delay.
The
below example demonstrates how to create a time log of when the batch
file is loaded, or for example, this could be used in the autoexec.bat
when someone logs into a computer that supports this file.
ECHO. |TIME > TIME COPY LOG +TIME
An
alternate, slightly more complicated method that, to our knowledge,
cannot be used in Windows NT, Windows 2000 or Windows ME would be the
following:
echo @prompt set date=$d$_set time=$t$h$h$h > {a}.bat %comspec% /e:2048 /c {a}.bat > {b}.bat for %%v in ({b}.bat del) do call %%v {?}.bat echo %date% %time% >> log
Another alternative is:
echo. |time |find "current" >> log
For the above batch file to work properly you must create a file called log, by typing edit log
and then save and exit the file, creating a 0 bytes file. If this file
is not created or not created properly you will receive the error
message Content of destination lost before copy.
A boot disk will allow you to boot off of a diskette instead of your hard drive. This diskette can be used to fix issues that may arise during the lifetime of your computer or to help load older MS-DOS games. Keep in mind this diskette is completely different than a Restore CD or Disc that may have been included with your computer.
After you have created a boot diskette, it is highly recommended that you write-protect the diskette to prevent possible computer virus infection and to help the diskette from being erased.
Creating a MS-DOS boot disk
Note:
These steps are for users who have MS-DOS installed on the computer. If
you have any version of Windows follow the below steps for your version
of Windows.
To create a MS-DOS diskette, begin by getting to the DOS directory by typing:
cd\dos
Once at the C:\DOS directory, skip to copying files.
Creating a Windows 3.X boot disk
Note: These steps are for users who have Windows 3.x installed on the computer.
To
create a Windows 3.x diskette, from Windows Program manager, click File
and then choose the option to Exit Windows, which will get you to a
prompt; at the prompt, type:
cd\dos
Once at the C:\DOS directory, skip to copying files.
Creating a Windows 95 boot disk
Note: These steps are for users who have Windows 95 installed on the computer.
In
Windows 95, Microsoft has created a new method of creating a bootable
recovery diskette. Unfortunately, however, this diskette does not
support CD-ROM support and is missing a few recommended files. To do
this, click Start / Settings / Control Panel / double-click the Add
Remove programs icon / click the Startup Disk and create disk.
Alternatively,
to create a Windows 95 boot diskette manually from Windows, click Start
/ Shutdown and choose the option to restart the computer in a MS-DOS
prompt. At the prompt, type:
cd\windows\command
Once at the C:\DOS directory, skip to copying files.
Creating a Windows 98 / ME boot disk
Note: These steps are for users who have Windows 98 or Windows ME installed on the computer.
An
excellent feature of Windows 98/ME is its boot diskette. Using Windows
to create you a Windows 98 boot diskette will give you all the needed
files as well as CD-ROM support. To create a Windows 98 boot diskette,
click Start / Settings / Control Panel / double-click the Add Remove
programs icon / click the Startup Disk and create disk.
Alternatively,
to create a Windows 98 boot diskette manually from Windows, click Start
/ Shutdown and choose the option to restart the computer in a MS-DOS
prompt. At the prompt, type:
cd\windows\command
Once at the C:\DOS directory, skip to copying files.
Copying additional files
NOTE: When
making a boot disk, if you are running "Stacker" or some kind of a
DoubleSpace or drive swapper program, this could not work
Once
you are in DOS and at the correct directory as instructed in the above
sections by operating system, you are ready to create your bootable
diskette. Insert a diskette that does not contain any information (it
will be erased).
At the prompt, if you have MS-DOS 6.2 / Windows 3.x / Windows 95 / Windows 98, type:
If
you are planning to use this diskette as a diskette to load games or
you feel that you need mouse support, you will need to copy the mouse
driver onto the boot diskette. The MS-DOS mouse driver is generally
mouse.com / mouse.sys. Locate this file and copy it to your bootable
diskette.
For CD-ROM support, visit our CD-ROM drivers page for information on loading your CD-ROM driver.
Once you have copied the above files, create an autoexec.bat and a config.sys. Get to the floppy drive by typing A:, once at the floppy drive, type:
copy con autoexec.bat [PRESS ENTER] @echo off [PRESS ENTER] LH A:\MSCDEX.EXE /D:CDROM [PRESS ENTER] (this line is used for your CD-ROM drive). LH A:\MOUSE.* [PRESS ENTER] (skip line if you did not copy mouse file, the * is either sys / com).
Press and hold CTRL + Z - this should return ^Z. Once this is displayed, press enter to copy the file.
copy con config.sys [PRESS ENTER] device=a:\himem.sys dos=high,umb device=a:\emm386.exe noems files=30 buffers=20 devicehigh=a:\oakcdrom.sys /d:CDROM (this line is used for your CD-ROM drive).
Press and hold CTRL + Z - this should return ^Z. Once this is displayed, press enter to copy the file.
Congratulations, after completing the above steps you should now have a bootable floppy diskette.
Creating a Windows NT boot disk
To
create a boot diskette you must have access to the i386 directory
located on your Windows NT CD or possibly your Hard disk drive.
Format the floppy diskette you wish to make a bootable Windows NT boot disk using the Windows NT machine.
Copy boot.ini, ntdetect.com and ntldr to the floppy diskette just formatted.
If you are using any SCSI devices that you need access to, you will also need to load these drivers onto the diskette.
Creating a Windows 2000 boot disk
To
create a Windows 2000 Professional bootable diskette you will need four
1.44MB diskettes and the Windows 2000 Professional CD.
Click Start / Run / browse to the CD-ROM drive. Open the "BOOTDISK" folder and double-click makeboot.exe and click ok to launch the program to create the diskette.
Users
can also easily create an Emergency Repair Disk by clicking Start,
Programs, Accessories, System Tools, and opening Backup. From the Backup
window, click the button for Emergency Repair Disk and follow each of
the steps.
Creating a Windows XP boot disk
Note: The
Microsoft Windows XP CD is a bootable CD and in many cases you should
not need a bootable floppy diskette. Booting from the Windows XP CD will
allow you to not only install/re-install Windows XP but will also allow
you to troubleshoot it.
Create MS-DOS bootable diskette
When formatting a floppy diskette, users have the option of creating a MS-DOS startup disk, follow the below steps to do this.
Place diskette in the computer.
Open My Computer, right-click the A: drive and click Format.
In the Format window, check Create an MS-DOS startup disk.
Click Start
Create Windows XP Setup diskettes
Microsoft
is beginning to phase out bootable floppy diskettes in favor of
bootable CD discs and has not included a method of easily creating a
bootable floppy diskette in Windows XP or from the CD. However,
Microsoft has downloads available for users who still need to create
bootable diskettes to install (not upgrade) Windows XP. These downloads
can be found through KB310994.
There are not many commands you need to learn in DOS to use it effectively,
but you do need to learn how to get "syntax" help. Originally there was (and
currently is) a HELP facility which is itself a command: help. Some versions of Windows
do not automatically install the Help command, however (Windows 95, for example).
Each command has a mini-help facility within it,
which is activated by adding just the parameter /? (forward slash, question mark)
to the command. But truly, typing helpcommandname is better
because it has a far smaller possibility of error -- do you really want to type
del /? or does help del feel safer? A mistype, for example missing
the forward slash (del ?) will delete every file in the current directory
that has a name one character long (with no extension). Mistyping the forward
slash as a back slash (del \?) will delete everything in the root directory
which is one character long. Granted, not too many files are like that, but
they certainly can be. "A" is a legal filename. And Windows doesn't save files
to the recycle bin that are deleted while in DOS mode! And formerly popular DOS programs
that might have helped you undelete DOS files are now usually not recommended
for Windows 95 machines (after that, I haven't checked...). As far as I know, if you delete a file in DOS these days
-- it's gone. So by all means delete when necessary, but always delete with care.
DOS Command Descriptions
The first
command you need to learn to use DOS is simply how to get help. Unbelievably, with Windows 95,
Microsoft stopped automatically loading the MS-DOS
HELP facility when you install Windows. This is the most important DOS command
of all and yet Microsoft choose not to load it automatically when Windows is
installed.
Fortunately, HELP is back, and in the meantime, Microsoft also completely
instituted the command-by-command help standards, so you can simply type the
command name and the add the two symbols /? (forward slash, question mark) after
the command. Some commands take more than one page to see; use the pipeline command
MORE (|more) to view the screens one at a time.
(Note: If you are (for some reason) running Windows 95, you can load the DOS HELP from
the Windows CD-ROM. It is in the \OTHER\OLDMSDOS directory. You need to load QBASIC.EXE, QBASIC.HLP,
HELP.HLP, and HELP.COM. They can be placed in the \WINDOWS\SYSTEM
directory. Placing them there makes them immediately available again to DOS users.
help
help
This command gives you a key to virtually everything you need
to use DOS effectively. Can't remember the format for the FORMAT command? Not
a problem! Type HELP FORMAT and press the ENTER key, and you've got everything
you need to use FORMAT! This is true for virtually every DOS command so if you
remember HELP commandname you won't have any problems.
Another way
to get help (or, if you don't install the HELP files suggest above, the ONLY way
to get help in Windows 95) is to use /? (slash, question mark) after any
command. This is faster and sometimes a more useful form of help, but it is generally
only a listing of options. HELP is usually a more verbose help facility
than /? is.
copy
copy
Once you know where to get help, the rest is easy. The whole
purpose of DOS is to let you get around the directory tree easily. You use DOS
to start applications (like my own P11.EXE program) and to copy files, delete
files, build places to put files, and compare files, and so on. Files, Files,
Files. That's what DOS is really for.
The #1 tool for file handling is the
COPY command. Specify the "from" file first, then the "to" file. COPY only copies
from within one directory at a time, but the "to" directory can be different.
For copying entire diretory structures, use XCOPY instead.
What makes COPY
so powerful is that you can use "wildcards" like * and ? within
the filename.
xcopy
xcopy
Like COPY, XCOPY can use wildcards to copy a file or group of
files to another directory. But XCOPY is more powerful because it has the ability
to copy an entire directory structure in one command. Use the /s option
to accomplish this. Use HELP XCOPY to learn more, of course!
cd (Change Directory)
cd
CD is the cold, hard way
of doing things, but sometimes it's the right way. What makes it cold and hard
is that in comparison to Norton's Change Directory (normally abbreviated NCD,
but I abbreviated it to C on my system), the DOS CD command requires you to type
the complete directory entry, all the way back to the root level! This is absurd.
NCD, on the other hand, lets you type in anything that's close, and it will search
your entire directory structure and plop you down right where you want to be.
For example, to go to the \p11\pumps\svgapump directory, I can just type in: c
svgap and immediately NCD will take me there. With CD, I would have to type
cd \p11\pumps\svgapump to accomplish the same thing. Saving keystrokes
is the name of the game. (That's why later in this tutorial, you'll learn to write
batch files.)
md (Make Directory)
md
MD will make a new directory. You can specify the entire directory
structure or just the new part, if you are already in the parent of the new part.
Got that? I didn't think so. Let's say you have a directory called \animals.
Let's say you are in that directory, having typed cd\animals at some point.
To create the directory \dogs as a subdirectory of \animals, you can type in md
dogs when you are in the \animals directory. Or, you can type in the full
md \animals\dogs from any directory. However, you can't make two directory
structures at once. \animals must exist before you can use MD to create \dogs.
CD and MD (and RD) are often used in conjunction with each other. If you use
MD to make a new directory, to then go into that new directory, all you should
have to do is just back up the command stack one command and change the M in MD
to a C. (That's why you need a command stack manipulator like CED. In plain DOS,
Function Key 3 will give you the last command, but only the last command.
CED will go back dozens of commands.)
It's very important to understand a
principal brought up in the last paragraph--that you never retype anything you
don't have to. Don't be fooled into thinking it's easier to retype than to find
the old command in the command stack and change a letter. First of all, it isn't.
And second of all, when you get to the DELETE (DEL) command, you really need to
not retype things! (read on...)
rd (Remove Directory)
rd
When you empty a directory
and wish to remove it entirely, you can use RD. RD will not delete the entries
(files) in a directory. They must already be deleted (the directory must be empty)
for RD to work. However, these two steps can be simplified by doing them in order.
Use the DEL command (described below) and then bring the command line back (using
your command stack manipulator). Change DEL to RD and a space character.
That way, you can be sure that you will remove the exact directory you just emptied,
because you don't retype the directory name. Actually, it's normally a three-step
process, since you would normally start with DIR filename, then change
DIR to DEL filename, and then change DEL to RD and a space.
For example, to remove the contents from the directory BARNEY and then remove
BARNEY, use the following three commands. Bring them back each time with your
command stack manipulator, and just change DIR to DEL and then DEL to RD
and a space:
dir barney del barney rd barney
You could, in theory, also use the command DELTREE to remove both the contents
and the directory. You could, but you should refrain from doing that, because
DELTREE is a dangerous command and should be used slowly, carefully, and
sparingly. It should be a special occasion to use DELTREE, but RD is an
everyday thing.
dir (Directory)
dir
DIR is the DOS way of getting a listing of a directory. Incredibly
weak, it nevertheless has the advantage of being exactly like DEL in the way it
handles wildcards and directories. Therefore, you can type in DIR *.txt, and it
will list all the files that end with an extention of .txt, and after you see
that that's what you want, you can change the DIR to DEL after retrieving the
command back, and you know that you'll delete only what you want. And save keystrokes
too!
ren (Rename)
ren (oldname) (newname)
REN is short
for RENAME. You can rename any file or files to any valid, unused
name(s). Wildcards work fine. You could rename a file by first copying it and
then deleting the original, but this means you would use the more dangerous DEL
command. Never use DEL if you don't have to! REN gives you a way not to use DEL.
As an added benefit, REN is faster than COPY/DEL, especially if it's a big file
or group of files.
del (Delete)
del
DEL is the electronic equivalent of a paper shredder. The only
way to recover files you have accidentally DEL'ed to death is with some complicated
software program that MIGHT or MIGHT NOT work, but then again it might give you
new gibberish. And if you DEL'ed star-dot-star (*.*) you can pretty much forget
most UNDELETE software programs from succeeding. Think of DEL as short for DISASTER
IF I DIDN'T MEAN THIS.
That being said, of course, DEL is the standard way
of deleting things. But because it's so final, you should almost always use DIR
before you use DEL. Here's the plan: first, use DIR to view the filenames you
wish to delete. Next, use your command-line buffer to get the same command back,
and type DEL over DIR. That way, you will be absolutely sure that you will only
DEL the things you just looked at with DIR. It's faster too, usually, than retyping
the thing you want to delete. But even if it weren't, this is the best way to
delete things.
By the way, whenever you type in DEL *.*, you should always
take your hands away from the keyboard and review what you are doing. Are you
on the right drive and in the right directory? Do you really want to do this?
Same is true for any DEL command with wildcards, at least pause for a second or
two, especially since the file recovery programs I mentioned work much more reliably
if you just need to recover a single file, but if you need to recover multiple
files, they are much less successful.
deltree (Delete Tree)
deltree
CAUTION!!!
DELTREE is brutal and can really mess you
up. Its power is of course, its virtue. With DELTREE you essentially combine the
DEL *.* command with the RD command, but it's even better because
you can delete all the subdirectories as well, all in one swoop. Definitely this
is a good command to know and respect. ALWAYS pause before hitting the ENTER
key with this command! I literally take my hands away from the keyboard
and read the line before I press ENTER when I use this command!
fc (File Compare)
fc
FC is short for
FILECOMP, or FILE COMPARE. You should always use this command to compare files
that are really important to you when you create a new copy. If you duplicate
software, use FC to be sure that the "masters" for the manufacturer or distributor
are the same as your own masters. FC takes too long, and systems are too reliable,
to use it all the time, for everything. Besides, when copying files on your hard
disk this command is not usually needed because a similar command takes its place:
In your AUTOEXEC.BAT file the command VERIFY=ON. VERIFY will normally cause DOS
to read back every file it writes, every time it writes it. At least, that's what
it's designed to do, but whether VERIFY always does that, with every file, on
every drive, well--I'm skeptical. So I use FC when it really matters.
diskcopy
diskcopy
DISKCOPY lets you make exact copies of master diskettes.
This is good for backup and small distribution purposes. If you use DISKCOPY to
copy a diskette to another diskette using the same physical disk drive, then DOS
will copy a piece at a time, and will prompt you to swap them back and forth until
it's done. Somehow, Microsoft hasn't thought of using swap space on the hard drive
so you would only have to swap the physical media once. Maybe some day it will
occur to them. There are shareware and other tools to do multi-disk copies, which
do use "image files" on disk, for larger runs. Beyond a few hundred copies, consider
a CD master or outside disk duplicator service.
diskcomp
diskcomp
When you make a "MASTER BACKUP" disk of something really
important, you should use DISKCOMP to be sure it is the same as the "ORIGINAL
MASTER" diskette.
edit
edit
EDIT is a fairly lousy editor. My actual ASCII text editor
of choice was an early version of BRIEF which I used for almost
everything. BRIEF was text-based and the only real problem was, everyone
agrees I could
have used a spell-checker if it had one but hey--it was fast. And it was
great for writing
batch files, something you'll be introduced to later in this document.
(Note:
As of 1997, I moved to Boxer/TKO from David Hamel. It's everything BRIEF
was,
and much, much more! (Note: As of 2007, Brief does not appear to be
available anymore, and I no longer do anything in DOS, so I don't use
Boxer, either.))
But for those without an ASCII text editor of choice,
we all have EDIT available to us from Microsoft. It beats the pants off of the
old EDLIN, but if you remember EDLIN, you probably wouldn't need to be reading
this.
EDIT is for writing batch files, and for editing batch files. That's
about all it's good for, but you'll probably find youself using it often enough
that you should get comfortable with it. Know how to delete a line, how to move
around the document, how to insert and change characters, and how to copy a section.
Just know how to get help in EDIT and then remember to use it when you need it.
(F1 is the help key in EDIT, by the way.)
mem (Memory)
mem
A lot of problems with running
programs in DOS has to do with memory, same as in Windows and just about everything
else, I guess. Many programs (including ours) tell you what amount of Conventional
memory and what amount of Expanded and/or Extended memory they need.
Knowing
these values, you can use MEM to see if you indeed have enough memory available
to run your application.
Use MEM /c|more to get more information, and
have it scroll a page at a time. (See memmaker, below, to learn what to
do if MEM turns up showing too little memory available.)
memmaker
memmaker
NOTE: As of Windows 95, Microsoft no longer seems to use
Memmaker.
When MEM, above, reports that you don't have enough Conventional
Memory, Expanded Memory, or Extended Memory, you can use MEMMAKER to (hopefully)
free some memory up.
MEMMAKER is a Microsoft program that tries to place programs which are in
Conventional memory somewhere else--who cares where, right? Usually it's in
a place called HIGH MEMORY, or UPPER MEMORY. DOS can actually directly access
one megabyte plus 64K of memory, but unfortunately useless screen modes take
about 30% of that area. MEMMAKER can make more Conventional memory available
by filling in some nooks and crannies in the total addressable 1 meg+64K area.
format
format
CAUTION!!!
FORMAT should be used for diskettes only.
You virtually never want to FORMAT your hard drive. If you did, you'd probably
start with a low-level format "just to be on the safe side" anyway. FORMAT is
for diskettes only! So, NORTON came up with a nice program called SF (SAFE FORMAT)
which will replace FORMAT and which will not allow you to accidentally format
your hard drive. I use SF instead of FORMAT, but if you use format, you can still
get the safety aspects of SF by renaming FORMAT.COM and then creating a batch
file called FORMAT.BAT and placing it in the C:\DOS directory. The batch file
uses the batch file command IF to only allow you to use A: or B: or a: or b:.
All other "options" are invalid.
prompt
prompt
PROMPT is a little thing, but you need it. The "infamous DOS
prompt" can be greatly improved. I use:
PROMPT $t $d$h$h$h $p$g
This goes in your AUTOEXEC.BAT file and will, as shown, cause DOS to display
a prompt consisting of the day of the week, the date, the time to the second,
the drive and current directory, and a greater-than sign. I like it that way.
Knowledge is power, you know.
redirection (> and <)
redirection (> and <)
Redirection (> and <, greater-than and less-than signs) allows you to send
(>) output of other commands somewhere else, or receive (<) input from somewhere
else. Output is often sent to a file instead of to the screen with this option.
For example to send the output of a DIR command to a file called mydir.txt, use
this:
dir > mydir.txt
This would take the output of
the DIR command and place it in a file called mydir.txt instead of displaying
it on the screen. Use two greater-than signs (>>) to append to an existing
file. You can also send output directly to the printer using the special destination
name prn (or prn:).
To receive input from a file rather than from the
keyboard, use < and then the name of the file which has the input lines that
you want to use.
pipes (|, a vertical line)
|
Piping takes the complete output of
one command and sends it to the next command (after the vertical bar). Pipes are
useful for many things, but probably the most common use of pipes are with the
more command to cause the output of other DOS commands to be displayed
on the screen one screen at a time. For example:
mem /c|more
MORE will display the piped output of the mem command to the screen
and when each screen full of information appears, MORE will wait for a keypress
before displaying the next screen.
Batch Files are such simple timesavers
that you'll want to be able to write and edit them yourself.
To learn to write
batch files, you can download any of our demos, all of which have simple batch
files to start them, and copy the code for them. It's pretty easy. Use EDIT to
create batch files you need to accomplish things you do more than once or twice,
or to develop series of commands you want to execute repeatedly.
Batch files
don't have to be big -- I have plenty of one-line batch files which I give short
names to and which might only execute one thing. Batch files can call other batch
files or jump to other batch files, which increases their usefulness substantially.
Batch files are time savers and they help you to do things quickly and efficiently
and the same way every time.
In order to save keystrokes, I often rename the
few programs I use regularly, like BRIEF.EXE which is renamed b.exe and placed
on my virtual drive for virtually instant access. (Note: as of 1997, I now use
BOXER by David R. Hamel, which is started with the initials TKO. Also, like many
people, I have finally made the complete switch to Windows 95 as the base operating
system on the computer, and no longer make use of a virtual drive for my individual
DOS sessions (since they would take too long to set up each time, and hard drives
are much faster.)
Here are some brief descriptions of IF, GOTO, and SHIFT.
Note that
these are specific to DOS batch files, and are not used at the command line. Also,
note that both IF and SHIFT involve the variables that are available in DOS, namely
%0 through %9. They contain the items between the spaces following the batch file
name on the command line. For example, a DOS command line might read:
RUNPRGMS.BAT GENI MCGA
In this example there are two variables after
the batch file name (RUNPRGMS.BAT).
%0 would be equal to GENI. %1 would be
equal to MCGA. In a batch file, you could put the following line to use the first
two variables:
P11RUN.EXE %0 %1
The command line which
the executible program (P11RUN.EXE) gets would depend on the values of %0 and
%1 at the time. Each parameter substitution would be separated by single spaces.
if
if
IF used in a batch file compares something on the left of a double equal sign
( == ) with something on the right. So if the thing on the left is %0 and the
thing on the right is %1, then IF %0==GENI would be TRUE in the above example
(the evaluator is case sensitive), and the operation that would follow it would
be executed. That might be GOTO, which can follow an IF comparison, or it might
be SHIFT, or many other things. You can also use IF NOT... In addition to comparing
variables (strings), you can compare the ERRORLEVEL number, or do an EXIST of
a file name.
It's often a good idea to check for a null variable separately.
This is done by doing something like this:
IF %0.==. GOTO NOPARAMETERS
goto
goto
This will jump immediately to a label name -- but note: ONLY the first 8 characters
are significant, and the first character is a : (colon), and I don't know if
it's counted as one of the eight significant characters. Labels can be ahead
or behind the GOTO, that is, anywhere else in the batch file.
GOTO PLACENAME
This batch file command would cause the batch
file interpreter to skip forward to the named location. Locations are named with
a colon in front:
:PLACENAME
shift
shift
This batch file command will shift variable %1 into variable
%0, variable %2 to variable %1, variable %3 to variable %2, variable %5 to variable
%4, and so on through %9. I'm not sure what happens to %9, I think it's eliminated
after its value has been being moved to variable %8 (you might want to run a test
to be sure of what happens) unless there were more parameters to begin with which
DOS can use to fill the 10th slot, in which case, it will move a new value in.
There are no parameters to the SHIFT command.
I used CED for a long time. Another popular
command stacker is called DOSKEY, for both MS-DOS and PC-DOS. The purpose of a
command stack manipulator is to let you get at previous DOS commands you typed
without having to retype them. Again, plain DOS only lets you get at the very
last one, which is sort of like having Alzheimer's disease. Unfortunately, if
you tend to use DOS or the DOS emulator from within Windows, repeatedly running
new sessions of DOS, a command stacker won't help much, because each session is
completely separate.
hdir
or some other 'advanced' directory file viewer
DIR is too simple, and
has no color. HDIR provides a much easier way to display a list of files in a
directory and the list is much easier to read than a DIR output. There are many
other similar tools. If you use HDIR, use CED's cedparms to rename HDIR as H,
and put HDIR in a root directory or better yet, on a virtual drive for fast access.
Norton CD
or some other Change Directory tool
Norton's NCD is good, but again,
use CED to change the name to C instead of NCD, and put it on a virtual drive
on your system.
File Find tool
Norton's FF
(FileFind) is good, so if you have Norton Utilities, you might as well use FF.
But there are a number of shareware tools that are just as good or better. You
need to be able to find any file you know the name of (or part of the name) anywhere
on a disk, or even across multiple disks. You should also be able to find files
with similar names so you can delete old duplicates and old work-in-progress files.
Using DOS by itself...
To actually use DOS properly, you have to have a few tools to go with it. DOS as installed by Microsoft is virtually crippled and very difficult to use.
Several companies supply the necessary tools. Some of them are free.
The tools I use are not the only choices, but they are the ones listed
below the list of commands, and they are each desribed below the list of
command descriptions.
The thing about DOS is how quickly
you can get things done. Fewer keystrokes. It's textual, and it's fast.
But to be really fast and easy, it needs some help. For some reason Microsoft
won't add a previous-commands buffer to DOS! (They store only the last command.)
And their official policy on ced, the one I prefer, is that it doesn't
work with WINDOWS. But I don't know of a better command line retrieval system
the ced. CED is a good program. Microsoft should make WINDOWS work with
it, or they should at least fix DOS to emulate its general capabilities.
Why I wrote this...
Someone once asked me: "Will you teach me DOS?"
So I wrote this.
This is 1996 (updated a bit in 1998 and again in 2001 (and even
again, in 2010...) as I write this, and
not everyone knows DOS anymore. (2010: Make that "hardly anyone has
even heard of DOS these days..."). But DOS is easy to learn (2010: if
you're a geek who likes to torment themselves) and it is a great way
to get things done in life! (2010: ditto)
Of course, our own
"P11"
program and all its applications ran in DOS so we wanted people to be at
least a little comfortable with it. Hence this document.
DOS is
considered the bad guy, especially by people at Microsoft, who 'dis' it
more than anybody, and so people are naturally a little afraid of DOS.
Some people think WINDOWS is better than DOS simply because it isn't DOS.
But the beauty of DOS from a user's standpoint is that it is fast and
easy to work with. The beauty from a developer's standpoint is that it
allows me to easily control the entire PC hardware and virtually all of
its timing capabilities.
I hope this little guide to vital DOS commands
and tools will convince you that DOS is alive and well, and just dandy for all
sorts of things. Please email me and let me know if
it did you any good!
Many thanks to those who have offered suggestions for improving
this little tome, and to the hundreds who have written letters of appreciation.
MS-DOS (pronounced /ˌɛmɛsˈdɒs/, em-es-dos; short for Micro Soft Disk Operating System) was an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating systems offering a graphical user interface (GUI), in particular by various generations of the Microsoft Windows operating system.
MS-DOS grew from a 1981 request by IBM for an operating system for its IBM PC range of personal computers. Microsoft quickly bought the rights to QDOS (Quick and Dirty Operating System), also known as 86-DOS,[1] from Seattle Computer Products, and began work on modifying it to meet IBM's specification. The first edition, MS-DOS 1.0, was launched in 1982.[2] The version shipped with IBM's PCs was called PC DOS.
Although MS-DOS and PC-DOS were initially developed in parallel by
Microsoft and IBM, the two products eventually went their separate ways.
During its life, several competing products were released for the x86 platform,[3]
and MS-DOS itself would go through eight versions, until development
ceased in 2000. Ultimately it was the key product in Microsoft's growth
from a programming languages
company to a diverse software development firm, providing the company
with essential revenue and marketing resources. It was also the
underlying basic operating system on which early versions of Windows ran
as a GUI.
MS-DOS was a renamed form of 86-DOS — informally known as the Quick-and-Dirty Operating System or Q-DOS [2] — owned by Seattle Computer Products, written by Tim Paterson[2]. Microsoft needed an operating system for the then-new Intel 8086 but it had none available, so it licensed 86-DOS and released a version of it as MS-DOS 1.0[2]. Development started in 1981, and MS-DOS 1.0 was released with the IBM PC in 1982[2].
(86-DOS, in turn, was written as an interim replacement for the delayed
CP/M-86, when Seattle Computer Products' needed an operating system to
sell with their 8086 processor card for the S-100 bus.) Tim Paterson is
considered the original author of DOS and he is called "The Father of
DOS"[2][n 1]
Originally MS-DOS was designed to be an operating system that could
run on any 8086-family computer. Each computer would have its own
distinct hardware and its own version of MS-DOS, similar to the
situation that existed for CP/M, and with MS-DOS emulating the same solution
as CP/M to adapt for different hardware platforms. To this end, MS-DOS
was designed with a modular structure with internal device drivers,
minimally for primary disk drives and the console, integrated with the
kernel and loaded by the boot loader, and installable device drivers for
other devices loaded and integrated at boot time. The OEM
would use a development kit provided by Microsoft to build a version of
MS-DOS with their basic I/O drivers and a standard Microsoft kernel,
which they would typically supply on disk to end users along with the
hardware. Thus, there were many different versions of "MS-DOS" for
different hardware, and there is a major distinction between an
IBM-compatible (or ISA) machine and an MS-DOS [compatible] machine. Some
machines, like the Tandy 2000,
were MS-DOS compatible but not IBM-compatible, so they could only run
software written exclusively for MS-DOS without dependence on the
peripheral hardware of the IBM PC architecture.
This design would have worked well for compatibility, if application
programs had only used MS-DOS services to perform device I/O, and indeed
the same design philosophy is embodied in Windows NT (see Hardware Abstraction Layer).
However, in MS-DOS's early days, the greater speed attainable by
programs through direct control of hardware was of particular
importance, especially for games, which often pushed the limits of their
contemporary hardware. Very soon an IBM-compatible architecture became
the goal, and before long all 8086-family computers closely emulated IBM's hardware,
and only a single version of MS-DOS for a fixed hardware platform was
needed for the market. This version is the version of MS-DOS that is
discussed here, as the dozens of other OEM versions of "MS-DOS" were
only relevant to the systems they were designed for, and in any case
were very similar in function and capability to the same-numbered
standard version for the IBM PC, with a few notable exceptions.
While MS-DOS appeared on PC clones, true IBM computers used PC DOS,
a rebranded form of MS-DOS. Ironically, the dependence on
IBM-compatible hardware caused major problems for the computer industry
when the original design had to be changed. For example, the original
design could support no more than 640 kilobytes of memory (the 640 kB barrier),
because IBM's hardware design reserved the address space above this
limit for peripheral devices and ROM. Manufacturers had to develop
complicated schemes (EMS and XMS,
and other minor proprietary ones) to access additional memory. This
limitation would not have been a problem if the original idea of
interfacing with hardware through MS-DOS had endured. (However, MS-DOS
was also a real-mode operating system, and the Intel x86 architecture
only supports up to 1 MB of memory address space in Real Mode, even on
Pentium 4 and later x86 CPUs, so for simple access to megabytes of
memory, MS-DOS would have had to be rewritten to run in 80286 or 80386
Protected Mode.) Also, Microsoft originally described MS-DOS as "an
operating system for Intel 8086-based microcomputers", and the 8086 CPU
(and its cousin the 8088) itself has only 1 MiB of total memory address
space.
Microsoft licensed or released versions of MS-DOS under different names like SB-DOS or Z-DOS[3]. Competitors released DOS systems such as DR-DOS and PTS-DOS that could also run DOS applications. The following versions of MS-DOS were released to the public:[4][5]
MS-DOS 1.x
Version 1.12 (OEM) - Compaq release of PC-DOS 1.10
Version 1.25 (OEM) - Microsoft repackaging of PC-DOS 1.10
MS-DOS 2.x - Support for 10 MB Hard Disk Drives and tree-structure filing system
Version 2.0 (OEM)
Version 2.1 (OEM)
Version 2.11 (OEM)
Version 2.2 (OEM)
Version 2.21 (OEM)
MS-DOS 3.x
Version 3.0 (OEM) - Support for larger Hard Disk Drives
Version 3.1 (OEM) - Support for Microsoft Networks
Version 3.2 (OEM)
Version 3.21 (OEM)
Version 3.25 (OEM)
Version 3.3 (OEM)
Version 3.3a (OEM)
Version 3.3r (OEM)
Version 3.31 (OEM) - Compaq 3.31 supports FAT16 and larger drives.
Version 3.35 (OEM)
MS-DOS 4.x - includes a graphical/mouse interface.
Version 4.01 (OEM) - IBM patched Version 4.00 before Microsoft released it.
MS-DOS 5.x
Version 5.0 (Retail) - includes a full-screen editor. A number of bugs required reissue.
Version 5.0a (Retail) - With this release, IBM and Microsoft versions diverge.
Version 5.0.500 (WinNT) - All Windows NT 32-bit versions ship with files from DOS 5.0
MS-DOS 6.x
Version 6.0 (Retail) - Online help through QBASIC. Disk compression and antivirus included.
Version 6.2 (Retail) - Microsoft and IBM alternate versions, IBM has 6.1, 6.3
Version 6.21 (Retail) - Stacker-infringing DBLSPACE removed.
Version 6.22 (Retail) - New DRVSPACE compression.
MS-DOS 7.x
Version 7.0 (Win95,95A) - Support for long file names. New editor.
Version 7.1 (Win95B-Win98SE) - Support for FAT32 file system
MS-DOS 8.0
Version 8.0 (WinME) - Integrated drivers for faster Windows loading.
Version 8.0 (WinXP) - DOS boot disks created by XP and later contain files from WinME. The internal DOS is still 5.0
Microsoft DOS was released through the OEM channel, until DRI
released DR-DOS 5.0 as a retail upgrade. With PC-DOS 5.00.1, the
IBM-Microsoft agreement started to end, and IBM entered the retail DOS
market with IBMDOS 5.00.1, 5.02, 6.00 and PC-DOS 6.10, 6.30, 7.00 and
2000.
A number of beta versions have surfaced on the Internet, such as 5.0
(a ten-diskette version in the same vein as 4.0), 7.00 beta 1 (based on
6.00), 7.00 beta 2 (based on 6.22). An OEM source package for 6.00, and a
late release of 6.2(b) have also been seen. These are not retail
versions.
On microcomputers based on the Intel 8086 and 8088 processors, including the IBM PC and clones, the initial competition to the PC DOS/MS-DOS line came from Digital Research, whose CP/M
operating system had inspired MS-DOS. In fact, there remains
controversy as to whether Q-DOS was more or less plagiarised from early
versions of CP/M code. Digital Research released CP/M-86
a few months after MS-DOS, and it was offered as an alternative to
MS-DOS and Microsoft's licensing requirements, but at a higher price. Executable programs for CP/M-86 and MS-DOS were not interchangeable with each other; much applications software
was sold in both MS-DOS and CP/M-86 versions until MS-DOS became
preponderant (later Digital Research operating systems could run both
MS-DOS and CP/M-86 software). MS-DOS supported the simple .COM and the more advanced relocatable .EXE executable file formats; CP/M-86 a relocatable format using the file extension.CMD.
Most of the machines in the early days of MS-DOS had differing system
architectures and there was a certain degree of incompatibility, and
subsequently vendor lock-in.
Users who began using MS-DOS with their machines were compelled to
continue using the version customized for their hardware, or face trying
to get all of their proprietary hardware and software to work with the
new system.
In the business world the 808x-based machines that MS-DOS was tied to faced competition from the Unix operating system which ran on many different hardware architectures. Microsoft itself sold a version of Unix for the PC called Xenix.
In the emerging world of home users, a variety of other computers
based on various other processors were in serious competition with the
IBM PC: the Apple II, early Apple Macintosh, the Commodore 64
and others did not use the 808x processor; many 808x machines of
different architectures used custom versions of MS-DOS. At first all
these machines were in competition. In time the IBM PC hardware
configuration became dominant in the 808x market as software written to
communicate directly with the PC hardware without using standard
operating system calls ran much faster, but on true PC-compatibles only.
Non-PC-compatible 808x machines were too small a market to have fast
software written for them alone, and the market remained open only for
IBM PCs and machines that closely imitated their architecture, all
running either a single version of MS-DOS compatible only with PCs, or
the equivalent IBM PC DOS. Most clones cost much less than IBM-branded
machines of similar performance, and became widely used by home users,
while IBM PCs had a large share of the business computer market.
Microsoft and IBM together began what was intended as the follow-on to MS/PC DOS, called OS/2.
When OS/2 was released in 1987, Microsoft began an advertising campaign
announcing that "DOS is Dead" and stating that version 4 was the last
full release. OS/2 was designed for efficient multi-tasking — an IBM
speciality derived from deep experience with mainframe operating systems
— and offered a number of advanced features that had been designed
together with similar look and feel; it was seen as the legitimate heir to the "kludgy" DOS platform.
MS-DOS had grown in spurts, with many significant features being
taken or duplicated from Microsoft's other products and operating
systems. MS-DOS also grew by incorporating, by direct licensing or
feature duplicating, the functionality of tools and utilities developed
by independent companies, such as Norton Utilities, PC Tools (Microsoft Anti-Virus), QEMM expanded memory manager, Stackerdisk compression, and others.
During the period when Digital Research was competing in the operating system market some computers, like Amstrad PC-1512,
were sold with floppy disks for two operating systems (only one of
which could be used at a time), MS-DOS and CP/M-86 or a derivative of
it. Digital Research produced DOS Plus,
which was compatible with MS-DOS 2.11, supported CP/M-86 programs, had
additional features including multi-tasking, and could read and write
disks in CP/M and MS-DOS format.
While OS/2 was under protracted development, Digital Research released the MS-DOS compatible DR-DOS
5, which included features only available as third-party add-ons for
MS-DOS (and still maintained considerable internal CP/M-86
compatibility). Unwilling to lose any portion of the market, Microsoft
responded by announcing the "pending" release of MS-DOS 5.0 in May 1990.
This effectively killed most DR-DOS sales until the actual release of
MS-DOS 5.0 in June 1991. Digital Research brought out DR-DOS 6, which
sold well until the "pre-announcement" of MS-DOS 6.0 again stifled the
sales of DR-DOS.
Microsoft had been accused of carefully orchestrating leaks about
future versions of MS-DOS in an attempt to create what in the industry
is called FUD (fear, uncertainty, and doubt) regarding DR-DOS. For
example, in October 1990, shortly after the release of DR-DOS 5.0, and
long before the eventual June 1991 release of MS-DOS 5.0, stories on
feature enhancements in MS-DOS started to appear in InfoWorld and PC Week.
Brad Silverberg, Vice President of Systems Software at Microsoft and
General Manager of its Windows and MS-DOS Business Unit, wrote a
forceful letter to PC Week (November 5, 1990), denying that
Microsoft was engaged in FUD tactics ("to serve our customers better, we
decided to be more forthcoming about version 5.0") and denying that
Microsoft copied features from DR-DOS:
"The feature enhancements of MS-DOS version 5.0 were decided and
development was begun long before we heard about DR-DOS 5.0. There will
be some similar features. With 50 million MS-DOS users, it shouldn't be
surprising that DRI has heard some of the same requests from customers
that we have." – (Schulman et al. 1994). [6]
The pact between Microsoft and IBM to promote OS/2 began to fall apart in 1990 when Windows 3.0 became a marketplace success. Much of Microsoft's further contributions to OS/2 also went in to creating a third GUI replacement for DOS, Windows NT.
IBM, which had already been developing the next version of OS/2,
carried on development of the platform without Microsoft and sold it as
the alternative to DOS and Windows.
As a response to Digital Research's DR-DOS 6.0, which bundled SuperStor disk compression, Microsoft opened negotiations with Stac Electronics, vendor of the most popular DOS disk compression tool, Stacker. In the due diligence
process, Stac engineers had shown Microsoft part of the Stacker source
code. Stac was unwilling to meet Microsoft's terms for licensing Stacker
and withdrew from the negotiations. Microsoft chose to license
Vertisoft's DoubleDisk, using it as the core for its DoubleSpace disk
compression[7].
MS-DOS 6.0 and 6.20 were released in 1993, both including the
Microsoft DoubleSpace disk compression utility program. Stac
successfully sued Microsoft for patent
infringement regarding the compression algorithm used in DoubleSpace.
This resulted in the 1994 release of MS-DOS 6.21, which had
disk-compression removed. Shortly afterwards came version 6.22, with a
new version of the disk compression system, DriveSpace, which had a
different compression algorithm to avoid the infringing code.
Prior to 1995, Microsoft licensed MS-DOS (and Windows) to computer
manufacturers under three types of agreement: per-processor (a fee for
each system the company sold), per-system (a fee for each system of a
particular model), or per-copy (a fee for each copy of MS-DOS
installed). The largest manufacturers used the per-processor
arrangement, which had the lowest fee. This arrangement made it
expensive for the large manufacturers to migrate to any other operating
system, such as DR-DOS. In 1991, the U.S. government Federal Trade Commission
began investigating Microsoft's licensing procedures, resulting in a
1994 settlement agreement limiting Microsoft to per-copy licensing.
Digital Research did not gain by this settlement, and years later its
successor in interest, Caldera,
sued Microsoft for damages. It was believed that the settlement ran in
the order of $150m, but was revealed in November 2009 with the release
of the Settlement Agreement to be $280m.[citation needed]
Microsoft also used a variety of tactics in MS-DOS and several of
their applications and development tools that, while operating perfectly
when running on genuine MS-DOS (and PC DOS), would break when run on
another vendor's implementation of DOS. Notable examples of this
practice included:
Microsoft's QuickPascal released in early 1989 was the first MS product that checked for MS-DOS by modifying the program's Program Segment Prefix
using undocumented DOS functions, and then checked whether or not the
associated value changed in a fixed position within the DOS data segment
(also undocumented). This check also made it into later MS products,
including Microsoft QuickC v2.5, Programmer's Workbench and Microsoft C v6.0[6].
The (once infamous) AARD code,
a block of code in the Windows 3.1 beta installer. It was XOR
encrypted, self-modifying, and deliberately obfuscated, using various
undocumented DOS structures and functions to determine whether or not
Windows really was running on MS-DOS[6].
Note that the Windows 3.0 beta code only gave a warning that Windows
would not operate properly on a "foreign" OS. It did in fact run just
fine on DR-DOS 6.0.
Interrupt routines called by Windows to inform MS-DOS that Windows
is starting/exiting, information that MS-DOS retained in an IN_WINDOWS
flag, in spite of the fact that MS-DOS and Windows were supposed to be
two separate products[6].
In 2011, MS-DOS is still used in some enterprises to run legacy
applications, such as this US Navy food service management system.
Today, MS-DOS is rarely used for desktop computing. Since the release of Windows 95, it was integrated as a full product used for bootstrapping and troubleshooting, and no longer released as a standalone product.
However the only versions of DOS currently recognized as stand-alone
OSs, and supported as such by the Microsoft Corporation are DOS 6.0 and
6.22, both of which remain available for download via their MSDN, volume license, and OEM license partner websites, for customers with valid login credentials.
MS-DOS is still used in embedded x86 systems due to its simple architecture, and minimal memory and processor requirements. The command line interpreter of NT-based versions of Windows, cmd.exe, maintains most of the same commands and some compatibility with DOS batch files.
All versions of Microsoft Windows have had an MS-DOS like command-line interface
(CLI). This could run many DOS and variously Win32, OS/2 1.x and Posix
command line utilities in the same command-line session, allowing piping
between commands. The user interface, and the icon up to Windows 2000,
followed the native MS-DOS interface.
Consumer Windows (up to 3.11, Win9x, WinME) ran as a Graphical User Interface (GUI) running on top of MS-DOS. With Windows 95,
98, and ME the MS-DOS part was integrated to give the illusion of a new
operating system. The command line accessed the DOS command line
(usually command.com), through a Windows module (winoldap.mod).
A new line of Windows, (Windows NT), boot through a kernel whose sole
purpose is to load Windows: there is no character-mode boot similar to
Consumer Windows, OS/2 or UNIX). The console runs as a Win32 session,
with the default processor cmd.exe being a feature-reduced
version of OS/2's version. The command session permits running of
various supported command line utilities from Win32, MS-DOS, OS/2 1.x
and POSIX.
The 32-bit Windows can run MS-DOS programs through the use of the NTVDM (NT Virtual DOS Machine). This launches a hacked version of MS-DOS 5.0. Launching the DOS command processor command.com
creates a DOS environment that allows DOS programs to communicate with
each other. It is not usually run by Windows, and the internal commands
of command.com are processed by the underlying Win32 processor (usually
cmd.exe, but could be 4nt).
The 32-bit CLI is usually referred to as the MS-DOS prompt. Although
the binary interface is no longer that found in PC-DOS etc., it is an
'interface', and not an API. The commands typed here, the batches etc.,
all resemble those of MS/PC-DOS in much the same way that the Linux/UNIX
commands resemble each other without underlying binary compatibility.
All versions of Windows for x86-64 and Itanium
architectures no longer include the NTVDM and can therefore no longer
natively run MS-DOS or 16-bit Windows applications. There are
alternatives in the form of Virtual machine emulators such as Microsoft's own Virtual PC, as well as VMware, DOSBox, and others.
The option to create a MS-DOS boot disk is still present in Windows 7.
From 1983 onwards, various companies worked on graphical user interfaces
(GUIs) capable of running on PC hardware. With DOS being the dominant
operating system several companies released alternate shells, e.g.
Microsoft Word for DOS, XTree, and the Norton Shell.
However, this required duplication of effort and did not provide much
consistency in interface design (even between products from the same
company).
Later, in 1985, Microsoft Windows
was released as Microsoft's first attempt at providing a consistent
user interface (for applications). The early versions of Windows ran on
top of MS-DOS and its clones. At first Windows met with little success,
but this was also true for most other companies' efforts as well, for
example GEM. After version 3.0 (1990), Windows gained market acceptance.
Later versions (Windows 95, Windows 98 and Windows Me) used the DOS
boot process to launch itself into protected mode. Basic features
related to the file system, such as long file names, were only available
to DOS when running as a subsystem of Windows. Windows NT ran independently of DOS but included a DOS subsystem so applications could run in a virtual machine
under the new OS. With the latest Windows releases, even dual-booting
MS-DOS is problematic as DOS may not be able to read the basic file
system.
Several similar products were produced by other companies. In the case of PC DOS and DR-DOS,
it is common but incorrect to call these "clones". Given that Microsoft
manufactured PC DOS for IBM, PC DOS and MS-DOS were (to continue the
genetic analogy) "identical twins" that diverged only in adulthood and
eventually became quite different products. Although DR-DOS is regarded
as a clone of MS-DOS, the DR-DOS versions appeared months and years
before Microsoft's products. (For example, MS-DOS 4, released in July
1988, was followed by DR-DOS 5 in May 1990. MS-DOS 5 came in April 1991,
with DR-DOS 6 being released the following June. MS-DOS 6 did
not arrive until April 1993, with Novell DOS 7, DR-DOS' successor,
following the next month.[9])
What made the difference in the end was Microsoft's desire to make
MS-DOS a better platform for running Windows. Both IBM (DOS 5.02) and
DRI (DOS 6 update) had to release interim releases for new undocumented
Windows functionality.
^ abcdSchulman, Andrew (1994). Undocumented DOS: A Programmer's Guide to Reserved MS-DOS Functions and Data Structures (2nd ed.). Addison-Wesley. ISBN0-201-63287-X.
MS-DOS (Microsoft Disk Operating System) is a single-user, single-tasking computeroperating system that uses a command lineinterface.
In spite of its very small size and relative simplicity, it is one of
the most successful operating systems that has been developed to date.
A Quick and Dirty History
When IBM launched its revolutionary personal computer, the IBM PC, in August 1981, it came complete with a 16-bit
operating system from Microsoft, MS-DOS 1.0. This was Microsoft's
first operating system, and it also became the first widely used
operating system for the IBM PC and its clones.
MS-DOS 1.0 was actually a renamed version of QDOS (Quick and Dirty
Operating System), which Microsoft bought from a Seattle company,
appropriately named Seattle Computer Products, in July 1981. QDOS had
been developed as a clone of the CP/M eight-bit operating system in
order to provide compatibility with the popular business applications of
the day such as WordStar and dBase. CP/M (Control Program for
Microcomputers) was written by Gary Kildall of Digital Research several
years earlier and had become the first operating system for
microcomputers in general use.
QDOS was written by Tim Paterson, a Seattle Computer Products employee, for the new Intel 16-bit 8086 CPU
(central processing unit), and the first version was shipped in August,
1980. Although it was completed in a mere six weeks, QDOS was
sufficiently different from CP/M to be considered legal. Paterson was
later hired by Microsoft.
Microsoft initially kept the IBM deal a secret from Seattle Computer
Products. And in what was to become another extremely fortuitous move,
Bill Gates, the not uncontroversial co-founder of Microsoft, persuaded
IBM to let his company retain marketing rights for the operating system
separately from the IBM PC project. Microsoft renamed it PC-DOS (the IBM
version) and MS-DOS (the Microsoft version). The two versions were
initially nearly identical, but they eventually diverged.
The acronym DOS was
not new even then. It had originally been used by IBM in the 1960s in
the name of an operating system (i.e., DOS/360) for its System/360
computer. At that time the use of disks for storing the operating system and data was considered cutting edge technology.
Until its acquisition of QDOS, Microsoft had been mainly a vendor of
computer programming languages. Gates and co-founder Paul Allen had
written Microsoft BASIC and were selling it on disks and tape mostly to
PC hobbyists.
MS-DOS soared in popularity with the surge in the PC market. Revenue
from its sales fueled Microsoft's phenomenal growth, and MS-DOS was the
key to company's rapid emergence as the dominant firm in the software
industry. This product continued to be the largest single contributor
to Microsoft's income well after it had become more famous for Windows.
Subsequent versions of MS-DOS featured improved performance and
additional functions, not a few of which were copied from other
operating systems. For example, version 1.25, released in 1982, added
support for double-sided disks, thereby eliminating the need to manually
turn the disks over to access the reverse side.
Version 2.0, released the next year, added support for directories, for IBM's then huge 10MB hard disk drive
(HDD) and for 360KB, 5.25-inch floppy disks. This was followed by
version 2.11 later in the same year, which added support for foreign and
extended characters.
Version 3.0, launched in 1984, added support for 1.2MB floppy disks and 32MB HDDs. This was soon followed by version
3.1, which added support for networks.
Additions and improvements in subsequent versions included support for multiple HDD partitions, for disk compression and for larger partitions as well as an improved disk-checking utility, enhanced memory management, a disk defragmenter and an improved text editor.
The final major version was 7.0, which was released in 1995 as part of
Microsoft Windows 95. It featured close integration with that operating
system, including support for long filenames and the removal of numerous
utilities, some of which were on the Windows 95 CDROM. It was revised in 1997 with version 7.1, which added support for the FAT32 filesystem on HDDs.
Although many of the features were copied from UNIX,
MS-DOS was never able to come anywhere close to UNIX in terms of
performance or features. For example, MS-DOS never became a serious
multi-user or multitasking
operating system (both of which were core features of UNIX right from
the start) in spite of attempts to retrofit these capabilities.
Multitasking is the ability for a computer to run two or more programs simultaneously.
The Rise of the GUI
The introduction of the Apple Macintosh in 1984 brought about a surge of interest in GUIs
(graphical user interfaces), and it soon became apparent that they
would eventually replace command line interfaces such as that used by
MS-DOS. Although many MS-DOS application programs created their own
primitive GUIs, this approach required duplication of programming
effort, and the lack of a consistent GUI among programs made it more
difficult for users to learn new programs.
It took Microsoft years until it was able to offer a fairly high quality
GUI of its own, with the introduction of Windows 95 in 1995 (or
arguably with Windows 3.0 in 1990). Microsoft had also begun work on a
joint project with IBM called OS/2, which was originally a
protected-mode version of MS-DOS with a GUI, but Microsoft soon
abandoned the project in order to devote more resources to the
development of Windows NT, a completely new operating system that was
independent of MS-DOS.
Protected mode and real mode are the two modes of operation supported by
the Intel x86 architecture. The former enables 32-bit memory
addressing, thereby permitting use of the extended memory that cannot be
easily accessed from real mode. This makes it possible to assign
separate memory areas to the operating system kernel (i.e., the core of the operating system) and to each process (i.e., program or task), thus resulting in much more stable multitasking than can be attained with real mode.
Early versions of Microsoft Windows ran under MS-DOS, whereas later versions were launched under MS-DOS but were then extended
by going into protected mode. Windows NT and its successors, Windows
2000 and XP, do not use MS-DOS; however, they contain an emulation layer
on which MS-DOS programs can be operated, mainly for backward
compatibility with legacy (i.e., old) software.
DOS Commands
MS-DOS has a relatively small number of commands, and an even smaller number of commonly used ones. Moreover, these commands are generally inflexible because, in contrast to Linux and other Unix-like operating systems, they are designed to accommodate few options or arguments (i.e., values that can be passed to the commands).
Some of the most common commands are as follows (corresponding commands
on Unix-like operating systems are shown in parenthesis):
CD - changes the current directory (cd)
COPY - copies a file (cp)
DEL - deletes a file (rm)
DIR - lists directory contents (ls)
EDIT - starts an editor to create or edit plain text files (vi, vim, ed, joe)
FORMAT - formats a disk to accept DOS files (mformat)
HELP - displays information about a command (man, info)
MKDIR - creates a new directory (mkdir)
RD - removes a directory (rmdir)
REN - renames a file (mv)
TYPE - displays contents of a file on the screen (more, cat)
Comparison between MS-DOS and Linux
MS-DOS and Linux have much in common, primarily because MS-DOS copied
many ideas from UNIX. However, there are some very fundamental
differences, including:
(1) Linux is a full-fledged multiuser, multitasking operating system,
whereas MS-DOS is a single-user, single-tasking operating system.
(2) MS-DOS does not have built-in security concepts such as file-ownership and permissions, which are fundamental to Linux.
(3) Linux has an inverted tree-like filesystem in which all directories and files branch from a single directory, i.e., the root directory, and its subdirectories. MS-DOS can have multiple, independent root directories, such as A:, C:, D:, etc.
(4) Linux uses forward slashes "/" to separate directories, whereas MS-DOS uses backslashes "\" for the same purpose.
(5) Linux filenames can contain up to 255 characters. MS-DOS filenames are limited to an eight characters plus a three-character extension and have restrictions on allowable characters. Also, filenames are case-sensitive in Linux, whereas they are not in MS-DOS.
(6) Linux has a vastly richer command set than does MS-DOS, with a
much greater number of commands and individual commands having greater
power, flexibility and ease of use. Commands are case-sensitive in
Linux, but they are not in MS-DOS.
(7) Although Linux and MS-DOS both have pipes and input/output redirection, the MS-DOS pipes use a completely different -- and inferior -- implementation.
(8) MS-DOS is not sufficiently flexible and efficient to serve as a
base for a high quality, general-purpose GUI (and thus it had to be
abandoned by Microsoft). In sharp contrast, Linux is an excellent base
for a GUI (and it is used as a base for the X Window System, which is extremely configurable and whose already excellent performance continues to improve).
MS-DOS Clones and Emulators
The great success of MS-DOS led to the development of several similar
operating systems, including DR-DOS, FreeDOS, OpenDOS and PC-DOS.
The most promising of these clones is FreeDOS, which is claimed to be
the only free operating system that is fully compatible with MS-DOS.
Development of FreeDOS was begun in 1994 by Jim Hall, then a physics
student at the University of Wisconsin-River Falls. His motivation was
Microsoft's announcement that it would stop supporting MS-DOS because of
its impending replacement by Windows 95.
Like MS-DOS, FreeDOS is lean and robust, and it can run on old hardware and in embedded systems.
A major improvement as compared with MS-DOS is the addition of options
to the commands. Moreover, FreeDOS is released under the GPL (although
some software in the distribution is covered by other licenses), thus
making it ideal for bundling a version of DOS into products without
having to pay royalties.
Because Linux was originally developed on PCs and at a time when MS-DOS
was the dominant PC operating system, a variety of tools were developed
to help developers and users bridge the gap between the two operating
systems. Among them is dosemu, a DOS emulator which is included with Red Hat and other distributions
and on which it is possible to run DOS programs. Emulators are also
available for running DOS on other Unix-like operating systems, even on
non-x86 processors.
mtools is a collection of utilities that make it easy to access
an MS-DOS floppy disk from Linux by merely inserting it into the floppy
disk drive and without having to use any mounting
commands (which can be tricky for inexperienced users). Included in
mtools are more than 20 commands, all of which are identical to their
MS-DOS counterparts except that the letter m is added to the
start of each of their names and forward slashes are used instead of
backslashes. For example, the MS-DOS command type a:\file1.txt to display the contents of a file named file1.txt that is located on a floppy disk would become mtype a:/file1.txt.
Outlook For the Future
Although it is widely believed that MS-DOS is an antiquated and useless
operating system with few features and capabilities, this is far from
correct. In fact, although not generally publicized, MS-DOS is still
used today by numerous businesses and individuals around the world. A
good analogy is the ancient programming language COBOL (introduced in
1960!), which is still in widespread use and, amazingly, accounts for
roughly half of all the computer code still in existence. Both MS-DOS
and COBOL have survived for so long because they are robust, relatively
simple and continue to get the job done with a minimum of maintenance.
In many cases, it was not MS-DOS itself that was the limiting factor in
system performance; rather, it was the hardware, including small
memories, slow CPUs and slow video cards. The capabilities of MS-DOS
have, in fact, continued to increase even after Microsoft Windows became
widespread. This is a result of continuing advances in the hardware and
the introduction of new or improved utilities and applications. DOS as a
whole is also being strengthened by the improvements that are being
made to the MS-DOS clones, particularly FreeDOS.
DOS will be around for many years into the future not only because of
the continued existence of legacy applications but also because of the
development of new applications. The main area of growth will most
likely be simple embedded applications, for which DOS is eminently well
suited because of its extremely small size, very reliable operation and
zero cost (in the case of FreeDOS).
DOS is so tiny, in fact, that it can fit on a single floppy disk and
still leave sufficient room on the same disk for an embedded program and
data files. Although there are many alternatives for embedded systems,
including embedded Linux and Microsoft Windows CE, DOS can be the best
choice if space is severely limited. Moreover, in contrast to FreeDOS,
Windows CE has the disadvantages of not being free and having various
licensing issues with which to contend.
The company has its headquarters in Palo Alto, California, United
States, and established an R&D Center in Cambridge, Massachusetts,
as well as one at the Time Warner Center in New York City, in 2005. VMware software runs on Windows and on Linux, and made its debut on Mac OS X in December, 2006.
VMware operated throughout 1998 in stealth mode with roughly 20 employees by the end of that year. The company was launched officially in February 1999 at the DEMO Conference organized by Chris Shipley.[7]
VMware delivered its first product, VMware Workstation, in May 1999[8] and entered the server market in 2001 with VMware GSX Server (hosted) and VMware ESX Server (hostless).[9]
In 2003 VMware launched VMware Virtual Center, the VMotion and Virtual
SMP technology. 64-bit support appeared in 2004. The company was also
acquired by EMC Corporation that same year for $625 million.[10]
In June 2006, VMware acquired privately-held Akimbi Systems.[11]
In August 2007, EMC Corporation released 10% of the company's shares in VMware in an initial public offering on the New York Stock Exchange. The stock debuted at 29 USD per share and closed the day at 51 USD.[12]
On July 8, 2008, VMware co-founder, president and CEO Diane Greene
was unexpectedly fired by the VMware Board of Directors and replaced by Paul Maritz, a retired 14-year Microsoft veteran who was heading EMC's cloud computing business unit.[13]
In the same news release VMware stated that 2008 revenue growth will be
"modestly below the previous guidance of 50% growth over 2007." As a
result, market price of VMware dropped nearly 25%. Then on September 10,
2008, Rosenblum, the company's chief scientist, resigned from VMware.
On September 16, 2008, VMware announced that they are collaborating with Cisco to provide joint data center solutions. One of the first results of this is the Cisco Nexus 1000V, a distributed virtual software switch that will be an integrated option in the VMware infrastructure.[14]
VMware acquired Tungsten Graphics, a company with core expertise in 3D graphics driver development on November 26, 2008.[15]
On August 10, 2009, VMware announced the acquisition of SpringSource, a leader in enterprise and web application development and management.[16]
The acquisition is seen by the industry as a strategic move of VMware
to become a leader in offering Platform as a Service (PaaS). The
acquisition also resulted in the expansion of VMware's education
services portfolio by the inclusion of SpringSource University and its
authorized training partner - SpringPeople Technologies.
On Tuesday, January 12, 2010, VMware acquired Zimbra, an open-source collaboration software tool, from Yahoo.
On Thursday, May 6, 2010, VMware acquired GemStone, to be operated under VMware's SpringSource division.
VMware software provides a completely virtualized set of hardware to the guest operating system.[17]
VMware software virtualizes the hardware for a video adapter, a network
adapter, and hard disk adapters. The host provides pass-through drivers
for guest USB, serial, and parallel devices. In this way, VMware
virtual machines become highly portable between computers, because every
host looks nearly identical to the guest. In practice, a system
administrator can pause operations on a virtual machine guest, move or
copy that guest to another physical computer, and there resume execution
exactly at the point of suspension. Alternately, for enterprise
servers, a feature called VMotion allows the migration of operational
guest virtual machines between similar but separate hardware hosts
sharing the same storage. Each of these transitions is completely
transparent to any users on the virtual machine at the time it is being
migrated.
VMware Workstation, Server, and ESX take a more optimized path to running target operating systems on the host than emulators (such as Bochs) which simulate the function of each CPU instruction on the target machine one-by-one, or dynamic recompilation
which compiles blocks of machine-instructions the first time they
execute, and then uses the translated code directly when the code runs
subsequently. (Microsoft Virtual PC for Mac OS X takes this approach.) VMware software does not emulate an instruction set for different hardware not physically present. This significantly boosts performance,[18]
but can cause problems when moving virtual machine guests between
hardware hosts using different instruction-sets (such as found in 64-bit
Intel and AMD
CPUs), or between hardware hosts with a differing number of CPUs.
Stopping the virtual-machine guest before moving it to a different CPU
type generally causes no issues.
VMware's products, which compete with those from companies such as Citrix and Microsoft, use the CPU to run code directly whenever possible (as, for example, when running user-mode and virtual 8086 mode code on x86). When direct execution cannot operate, such as with kernel-level and real-mode
code, VMware products re-write the code dynamically, a process VMware
calls "binary translation" or BT. The translated code gets stored in
spare memory, typically at the end of the address space, which segmentation
mechanisms can protect and make invisible. For these reasons, VMware
operates dramatically faster than emulators, running at more than 80% of
the speed that the virtual guest operating-system would run directly on
the same hardware. In one study VMware claims a slowdown over native
ranging from 0–6 percent for the VMware ESX Server.[19]
VMware's approach avoids some of the difficulties of virtualization
on x86-based platforms. Virtual machines may deal with offending
instructions by replacing them, or by simply running kernel-code in
user-mode. Replacing instructions runs the risk that the code may fail
to find the expected content if it reads itself; one cannot protect code
against reading while allowing normal execution, and replacing in-place
becomes complicated. Running the code unmodified in user-mode will also
fail, as most instructions which just read the machine-state do not
cause an exception and will betray the real state of the program, and
certain instructions silently change behavior in user-mode. One must
always rewrite; performing a simulation of the current program counter in the original location when necessary and (notably) remapping hardware code breakpoints.
The VMware product line can also run different operating systems on a
dual-boot system simultaneously by booting one partition natively while
using the other as a guest within VMware Workstation.
VMware Workstation (first product launched by VMware in 1999). This software suite allows users to run multiple instances of x86 or x86-64 -compatible operating systems on a single physical PC.
VMware Fusion provides similar functionality for users of the Intel Mac platform, along with full compatibility with virtual machines created by other VMware products.
VMware Player
For users without a license to use VMware Workstation or VMware Fusion,
VMware offers this software as freeware product for personal use. While
initially not able to create virtual machines, this limitation was
removed in version 3.0.1
VMware markets two virtualization products for servers:
VMware ESX (formerly called "ESX Server"), an enterprise-level product, can deliver greater performance than the freeware VMware Server, due to lower system overhead.
VMware ESX is a "bare-metal" product, running directly on the server
hardware, allowing virtual servers to also use hardware more or less
directly. In addition, VMware ESX integrates into VMware vCenter, which offers extra services to enhance the reliability and manageability of a server deployment, such as
VMotion - the capability to move a running virtual machine from one ESX host to another and faster than some other editions
Storage VMotion - the capability to move a running virtual machine from one storage device to another
DRS - Dynamic Resource Scheduler - automatic load balancing of a ESX cluster using VMotion
HA - High Availability - In case of hardware failure in a cluster,
the virtual servers will automatically restart on another host in the
cluster
VMware ESXi
(formerly called "VMware ESX 3i"), is quite similar to ESX, but
differentiates in that the Service Console is removed, and replaced with
a minimal BusyBox installation. Disk space requirements are much lower than for ESX and the memory footprint
is reduced. ESXi is intended to be run from flash disks in servers but
can be run from normal disks. VMware ESXi hosts can't be managed
directly from the console, all management is performed through a
VirtualCenter Server.[24] In July 2008, VMware decided to give ESXi away for free.
VMware Server (formerly called "GSX Server", now obsolete[25]) is also provided as freeware for non-commercial use, like VMware Player, and it is also possible to create virtual machines with it. It is a "hosted" application, which runs within an existing Linux or Windowsoperating system.
VMware ThinApp, one of the most recent products from the company
VMware vCenter Converter (VMware Converter) comes in both
Enterprise ($, bundling and entitlement with vCenter Server) and
Standalone (free) versions and is designed primarily for the following
tasks:[26]
Convert a physical machine into a virtual machine; referred to as Physical-to-Virtual or P2V.
Convert a virtual machine of one type into another (V2V)
Run automated configuration tasks on VMware ESX/ESXi servers.
Converted VMs are compatible with VMware ESX/ESXi, VMware Server and
VMware Workstation. A P2V conversion can be done from any physical
machine running Microsoft Windows (XP or later) or Linux based (Linux
only works on Standalone version). Conversions can be managed from a
centralized console allowing for multiple conversions at the same time
(using the Enterprise version). VMware vCenter Converter replaces[update]
the older VMware products "P2V Assistant" and "Importer". P2V Assistant
allowed users to convert physical machines into virtual machines; and
Importer allowed the import of virtual machines from other products into
VMware Workstation.
VMware ACE provides a means of distributing secured virtual desktops to networked client PCs.
VMware ThinApp, formerly Thinstall, is a virtualization suite capable of creating portable software ("portable apps"). This software enables applications to execute without being previously installed.
VMware Infrastructure is a collection of VMware products used to manage a VMware ESX/ESXi server environment.
VMware vSphere
is a "cloud OS". VMware vSphere 4 was originally named VMware Virtual
Infrastructure (VI) 4 and is capable of managing large pools of
infrastructure, including software and hardware[27] both from internal and external networks.
The VMware Tools package adds drivers and utilities to improve
the graphical performance for different guest operating systems,
including mouse tracking. The package also enables some integration
between the guest and host systems, including shared folders, plug-and-play devices, clocksynchronisation, and cutting-and-pasting across environments. VMware Inc makes VMware Tools available for Microsoft Windows, Linux, Sun Solaris, FreeBSD, and Novell NetWare guest systems.[28]
On September 11 at VMworld 2007, VMware announced that large portions
of VMware Tools for Linux, Solaris, and FreeBSD guests were released
under GPL and GPL-compatible licenses. They also announced the creation
of the Open Virtual Machine Tools ("open-vm-tools") project on
Sourceforge.net.[29]
VMware's promontory headquarters at 3401 Hillview Avenue in Palo Alto, California
After you have created a boot diskette, it is highly recommended that you 
