DOS DISK OPERATING SYSTEM DOS is required to operate any computer. It may have another name but there is an operating system. The first set of instructions when a computer is turned on comes from a BIOS chip or chips. BIOS is the BASIC IN OUT SYSTEM. This activates the display card, tests the display card, memory, and other various processor functions, and then says look for more instructions, DOS, first from the A floppy drive or second from a C hard drive. If DOS is found, it is booted or read in and activated. This supplies the necessary instructions on how the computer is to work with the various components and programs. It also gives us various utilities. DOS has evolved from various versions and features from CPM to MS DOS 6.22 from Microsoft or PC DOS 7.0 from IBM. Digital research or DR DOS is another system as is Novell, OS2, Concurrent DOS, and Windows 95. Windows 3.1 is only an enviroment that operates on top of DOS. In Windows 95, it is combined and can not be separated. DOS is on disk rather that a set of chips, so it can be upgraded with new features. DOS is both an operating system and a set of utilities. 3 files make up the actual operating system: IO.SYS, MSDOS.SYS, and COMMAND.COM. IF any of these are missing or corrupted, the system won't boot. Command.com also contains internal commands or utilities within it such as drive designators A: B: C: D: DIR TYPE CD CD\ CD.. Copy CLS REN DEL DATE TIME PROMPT PATH and others. External commands like DISKCOPY, FORMAT, XCOPY, MEM, SYS, and a hundred more should be in a separate directory of the hard drive. The 3 operating system files should be the first files on that hard drive. IBM and MS DOS are similar but different. They can not operate together. Also, you can not mix DOS versions which does happen sometimes, especially when copying files between computers. DOS is purchased or obtained first on floppy disk and is transferred or installed onto the hard drive. A separate emergency boot disk should also be made as well as a backup copy of the original DOS disks. Every new computer loaded with DOS should either come with a set of floppy disks or a procedure to make these disks from DOS on the hard drive. This should be done immediately. DOS is not as complicated as you may think. Out of 130 plus commands, only a few need be learned. A few simple rules with the commands and you can learn it. First, you must understand that it is necessary to organize your hard drive much like a file cabinet and folders. Each program needs to be in a separate Directory or Subdirectory. The first area of the hard drive where it all starts is called the ROOT Directory. The 3 operating system files, configuration files, and certain special files are the only files that should be in the root directory. You must first understand drive designators A: B: C: D: etc. The colon is part of the letter drive and must never be separated. That is the difference between the drive designator and a alphabet letter word. We switch between drives simply by issueing the command a: . No command is complete without hitting the ENTER key. This will be assumed from hereon. You must understand the slash symbol. The forward slash / and the back slash \ mean different things. You will use the back slash \ as we move around on the hard drive directories. The forward slash / is usually used with some commands to add on features or switches. Directories are created with the MD command, make directory. MD GCO will create a directory called GCO to store programs or files. CD GCO will switch your operations into directory called GCO. CD\ will return you to the ROOT DIRECTORY. CD means change directory. DIR will give you a directory listing for the directory you are in. You can create subdirectories inside directories, again with the MD command. If you build a complicated directory and subdirectory structure, you can view this structure with the TREE command. If you are within a subdirectory and wish to move only one step back instead of to the ROOT DIRECTORY, you use the CD.. command. If you are in a directory and want to move to another directory, you can use CD\DOS to jump from the GCO directory to the DOS directory. We can remove or erase a directory with the RD command. RD GCO will delete the directory as long as there is no files in the directory. If there are files in the directory, and we want to remove the directory and all files in it, type DELTREE GCO. We could also have DELeted the files and then used RD. The little flashing curser as it's called tells you the computer is waiting for information. There is a PROMPT that allows you to see where you are within the system. The prompt can be set up in many customized ways but the most helpful is having the disk drive and directory prompt shown at all times in DOS. When you move about, you can see where you are. It is created or modified in a configuration file. DATA, the information you create, as opposed to programs you buy, should be stored in a separate directory from your program. This will help protect both your programs and data and make it easier to backup your data. Information in your computer is subject to many kinds of failures and accidents and it should become part of your daily computer routine to safegard your data. DOS allows us to use file names with certain limitations. The file name can be 1 to 8 characters long including letters and numbers, a period which we usually call dot and an extension of 0 to 3 characters. Most files have extensions. Extensions tell programs or us the user how that file is used. Actual programs that run usually have an EXE or COM extension. Batch files are groups of commands that have a BAT extension. A program such as word perfect is actually made up of hundreds of small programs and utilities all working together. There are many other extensions that are overlays to the working programs. Sound files can have WAV or MOD extensions while pictures can have extensions such as BMP, GIF, PCX, TIF, etc. We usually name files we create with names we can remenber. Date and Time Commands allow you to either read or reset your time. MEM in new DOS 6 will give you a listing of your computers memory and how it's used. CLS issues the clear screen command to remove all but the prompt from your screen. The COPY Command is easy once you learn its full command syntex. It operates several ways depending on where your prompt is and how you want to use it. If you have a file called letter.txt in the WPDOC directory, there are several ways to coy it to floppy disk. We can issue the command from the root directory, the WPDOC directory on the C Drive or from the floppy where we want to put the file. From the root directory, issue the full command COPY C:\WPDOC\LETTER.TXT A: You simply told DOS to copy the file letter.txt in the WPDOC directory to Drive A: Seems logical. So is all the rest of DOS. When the file is transferred, you get a message one file copied. If you are already in the WPDOC directory, you can simplify the command to COPY LETTER.TXT A: If you are at the A: prompt, you can modify the command to COPY C:\WPDOC\LETTER.TXT . It knows to copy to the A: drive because you are there already. You can also use what we call wildcards. COPY *.TXT A: will copy all files with the extension txt to the a: drive. COPY *.* A: will copy all files in that directory to the a: drive untill you run out of disk space. The FORMAT command is quite important. Files can not be copied to a disk that has not been previously formatted. You will probably store some backups or file copies on floppy so you will need to learn this command. FORMAT A: It is possible to have a defective disk that might give you an error or you forgot to insert the floppy disk. You must by the way use floppy disks that match your floppy drive. The most common disk is the 3.5 inch high density disk formatted to 1.44 Megabytes. A 3.5 inch double density or extra high density is not the one to use unless that is what your system uses. The second most common is the 5 1/4 inch high density 1.2 megabyte disk. Don't confuse this with double density which works on older computers that contains only 360 KB. The density of the disk material is different. There are also other problems concerning 360K disks that will not be discussed here. Never issue the command FORMAT C: as this will destroy all the data and programs on the hard drive. Formatting a floppy disk places an address at the start of each electronic sector location on concentric circles called tracks. Every location on the floppy that can store data has a unique address. A file allocation table is also created during the format called the FAT which stores these addresses and makes a table of where to find these files as we copy them to disk. It is possible that the tracks, FAT, or boot sector may become damaged over time and the floppy may no longer be able to produce readable data. Disks should not be stored near magnetic items such as speakers, computer monitors, TV's, nor should they be in direct sunlight or high humidity. When data is created, it is many times created in a form usable only by that program. For instance, word processors insert data about font sizes, letter format, spacing, tabs, etc and it is not pure text. For this reason, a letter created on Microsoft Word may not be readable on DISPLAY WRITE and visa versa. Certain configuration files for the computer startup and for many programs are in pure ASCII text and if these configuration files were to be created or modified by most word processors, they would not be pure text. DOS gives use several utilities to deal with pure text for these purposes. One is called EDIT. We can create a file called LETTER.TXT with EDIT and later modify it. We could actually create all our letters with EDIT but there are no special functions for tabs, fonts, etc. Your computer uses 2 special configuration files that are read in when your computer boots, immediately after command.com is loaded. The first is the CONFIG.SYS and the second is AUTOEXEC.BAT. Both are pure ASCII text. Within these files are some DOS commands issued to the computer as it boots. A typical config.sys is DEVICE=C:\DOS\HIMEM.SYS DOS = HIGH FILES=35 BUFFERS=25 A memory manager called himem.sys is loaded and dos is loaded higher than normal to make way for larger programs. 35 Files are allowed to be open at one time and 25 memory buffers are reserved for DOS. A typical autoexec.bat would be @echo off prompt $p$g path=c:\dos;c:\;c:\wp60; c:\mouse\mouse.com type menu.txt Here we have the echo turned off so we do not see the actual commands issued by the autoexec.bat just to keep the screen less cluttered. The prompt line sets up a good prompt mentioned earlier so we can track where we are. The path statement allows us to issue commands without actually being in a certain program directory where that command might be. The next line activates the mouse in the mouse directory. The last line would bring up a menu of commands. There are times when we are booting the computer and something isn't working just right. DOS 6.2 allows us to use the F5 or F8 key as the computer boots and gives the message Starting MS-DOS to actually interupt the booting process. The F5 key stops the configuration files from being used. The F8 key makes the configuration files load one line at a time for troubleshooting. We can also create short files with the copy command but we can NOT modify them with the copy command. COPY CON CONFIG.TXT will start to create a config.sys file. WE now type in the lines as we want like in the example above and close or end the file with a control Z. Hold the control key down and type the letter Z. Remember to hit the ENTER key afterwards. We can look at the config file or any pure text file with the TYPE command. TYPE CONFIG.SYS will display the config.sys. We can't modify it with this but its a quick way to view it. Sometimes, there are readme files that come with programs with installation information. If it is a long text file, the type command would make it fly across the screen so fast, you couldn't read it. The more command will solve this problem. TYPE README.TXT|MORE and only one screen page at a time will scroll by. The | symbol used is above the \ key on most computers. If we create a file called letter.txt and we want to rename it to another name such as JIM.001, we simply type REN LETTER.TXT JIM.001. We can also delete this file by typing DEL JIM.001. WE are urged to backup copies of disk programs we buy. We can do this with the DISKCOPY command. Simply type DISKCOPY A: A: and you can make a duplicate of the same type disk. Simply have a blank disk ready. DISKCOPY will also format a blank disk if it is not already. DISKCOPY must work from one disk to another of the exact type, not 3.5 inch to 5 1/4 inch. There is a command called DOSKEY. We use this when we are doing alot of work in DOS. It allows us to recall last DOS commands used by pressing the arrow keys. Each disk, floppy or hard drive, has an electronic label that can show information that can be useful. Backup disks show a label stating it's a backup disk. Disks from manufacturers read disk 1 disk 2 etc on the label. When you format a disk, you are usually asked for a volume label name. You usually just hit enter. You could use a date or name the disk with the LABEL command. Just type LABEL and follow the directions. Be sure you are logged onto the disk you want to label. WE can make files disappear or hide them or unhide them or make then read - only (unerasable) with the ATTRIB command. Just type ATTRIB in any directory and watch what happens. In the root directory, you will see at least 2 or 3 hidden files relating to DOS. You do not want to change files just for the fun of it. Hidden files sometimes also can not be found by programs to use. You could make the config.sys and autoexec.bat read only so they would not be accidently erased. An example to make the config file read only would be ATTRIB +r config.sys . Sometimes, something goes wrong with DOS and your computer won't boot. If you have your emergency boot disk in hand, boot your computer off floppy drive emergency disk and type SYS C: and if you made the disk correctly, you should get a message "system transferred" with in about a minute. SmartDRV is a disk caching program that speeds up certain disk operations. It goes in the autoexec.bat and is safe with the newer DOS 6.2. Earlier versions had some problems that actually caused data loss. Even the version in the windows directory should be replaced unless you have windows 3.11. SETVER is a command that allows you to run a DOS utility from an older DOS version. This was used primarily for BACKUP and MSCDEX. If you have DOS 6.2 or later and don't use the DOS BACKUP command, you could eliminate SETVER if your CD ROM used MSCDEX from the DOS directory instead of the CD ROM Utility directory. MSCDEX is one of two files required to activate a CD ROM Drive. The first is a specific driver supplied by the CD ROM manufacturer and operated from the CONFIG.SYS. MSCDEX is setup in the autoexec.bat and references a device name in the config.sys to tie the two together. The CD ROM disk installs this when the drive is installed. The extra parameters in the line have to do with addresses and particular setups. EMM386.SYS is a memory manager. It was basically an expanded memory manager in early DOS versions, but is required as both extended and expanded memory manager in DOS 6.2 and later. MEMMAKER is a DOS utility to set up your memory manager and load as much of DOS and other drivers above 640K (HIGH) as possible. Most computers need managed memory drivers and DOS uses HIMEM and EMM386. Another utility called QEMM may be necessary to free more DOS memory if HIMEM can't do the job. If depends on what drivers you use and how many. Do not use MEMMAKER if your computer already has QEMM. If your computer has HIMEM.SYS in the config.sys, you can type MEMMAKER and follow the instructions to see if you are properly set up. You will be rebooting the computer 3-6 times automatically. Some users who use graphics alot require a utility called ANSI.SYS to be setup in the CONFIG.SYS. This activates special graphic features of your display card. Some BBS systems can also send ANSI graphics and you can enjoy them if this is activated. The line in the config would be DEVICE=C:\DOS\ANSI.SYS. There is a file in the root directory called WINA20.386 which is required to run windows in enhanced mode. If you experience trouble with windows, look to see it its still there. It is installed when DOS is first installed. You should check your hard drive with the SCANDISK command every so often. If checks disk and file operations. If you get an error message, follow the directions on the screen. CHKDSK was a similar command before SCANDISK came out and although CHKDSK is still included, use SCANDISK to fix any errors. EXPAND is the command to uncompress DOS utilities from the master disk that came with your system. Files are compressed to save space and they will not run unexpanded. Compressed files appear like sys.co_ . The underline means its compressed.EXPAND SYS.CO_ SYS.COM will uncompress sys.co_. There is a procedure (DEFRAG) that will fine turn your system after it has been running for several months. Your programs and data get moved all over your hard drive as you add and erase files or programs. If you have added and then deleted programs, consider running DEFRAG that comes with DOS. It will put your programs back together that have become "shattered" over the hard drive speeding up your hard drive access.  MODE Mode is very powerful and complicated. It performas many tasks such as displaying system status, changing system settings, or reconfiguring ports or devices. MODE (Configure Printer) MODE LPTn: c,l,r LPTn Specifies parallel port LPT1 LPT2 LPT3 in range 1,2,3 COLS=c Specifies the number of characters (columns) per line: 80 or 132. default value is 80 LINES=lSpecifies the vertical spacing and the number of lines per inch: 6 or 8. The default value is 6. RETRY=rSpecifies the retry action to take if a time-out error occurs B Return "busy" from a status check of a busy port. E Return an error from a status check of a busy port. P Continue retrying until printer accepts output. R Return "ready" from a status check of a busy port. N Take no retry action (default value). MODE (Configure Printer) MODE lpt2:80,8 80 characters per line and 8 lines perinch on LPT2 MODE (Configure Serial Port) MODE COMm: b,p,d,s,r COMm (COM1, COM2, COM3, or COM4). BAUD=b Specifies the first two digits of the transmission rate in bits per second. The following list shows each valid value for b and its related rate: 30 300 baud 12 1200 baud 24 2400 baud 96 9600 baud 19 19,200 baud PARITY=pSpecifies how the system uses the parity bit N (none), E (even), O(odd), M (mark), or S (space) DATA=d Specifies the number of data bits in a character range 5 through 8 The default value is 7 STOP=s Specifies the number of stop bits that define the end of a character 1,1.5, or 2. the default value is 1 RETRY=rSpecifies retry action if a time-out error occurs when MODEattempts to send output to a serial printer MODE (Display Device Status) MODE [device] [/STATUS] Displays the status of one or all of the devices installed on your system. Type MODE MODE (Redirect Printing) Redirects output from a parallel port to a serial communications port. MODE LPTn[:]=COMm[:] LPTn Specifies the parallel port. Valid values for n are 1- 3. COMm Specifies the serial port. Valid values for m are 1 - 4. Example: you want to set up your system so that it sends parallel-printer output to a serial printer. You must use the MODE command twice.First you use MODE to configure the serial port; second you use MODE to redirect parallel-printer output to the serial port. Example: Serial printer operates at 9600 baud with even parityconnected to COM1, you type: mode com1 48,e,,,b & mode lpt1=com1 To return to parallel port printing, type mode lpt1 XCOPY Is a powerful copy command and you must be precise in using it. It will copy directories as well as files. It will put files exactly where its told including if you forget a path, it will place files in root directories. XCOPY C:\WINDOWS\*.* C:\W\ /S WILL COPY the entire windows directory to a backup directory called W including subdirectories. XCOPY C:\*.* D:\ /S will copy everything on your C hard drive to your D hard drive. XCOPY C:\WPDOC\*.* A: /s will copy all your files from word perfect document directory to a floppy in a providing the file sizes are not exceeded and provided WPDOC is the name of the directory where your files are located. HELP is a very powerful command in DOS 6. Type HELP XCOPY or any other comand you want and you will get tons of information without cracking open a book. The BACKUP command will be covered in detail in a separate document but briefly, BACKUP C:\*.* A: /S will backup your entire hard drive including all directories provided you have enough floppies. RESTORE A: C:\*.* /S will restore the backup. To backup one directory called WPDOC where it is too big for a single floppy, type BACKUP C:\WPDOC\*.* A: /s . To restore it, type RESTORE A: C:\WPDOC\ /S . Use more than one set of backup disks and have several sets of backups to rotate from. MSBACKUP requires no parameters but can be quite fustrating because you must go through a whole setup procedure before it will work. Simply type MSBACKUP at the DOS prompt and follow instructions.