Working in DOS

DOS is a true operating systemDOS is a true operating system An operating system does 4 things:An operating system does 4 things:

– it must communicate with the hardwareit must communicate with the hardware– it must create a user interfaceit must create a user interface– must allow users to use and manage must allow users to use and manage

programsprograms– must allow users to add, move and delete must allow users to add, move and delete

the installed programsthe installed programs

DOS Until version 5.0 you could only get DOS Until version 5.0 you could only get DOS

on a PC and not off the shelfon a PC and not off the shelf Memorize chart on page 520Memorize chart on page 520 Files in DOS-Files in DOS-

– Filename no longer that 8 charactersFilename no longer that 8 characters– Extension up to 3 charactersExtension up to 3 characters– No spaces in filename or extensionNo spaces in filename or extension– Cannot use /\[]<>+=;,*?Cannot use /\[]<>+=;,*?

REMEMBER WIN 95/98 DOES HAS 255 REMEMBER WIN 95/98 DOES HAS 255 CHARACTER LIMITCHARACTER LIMIT

DOS

DOS cannot support more than 2 floppy DOS cannot support more than 2 floppy drivesdrives

Files organized into directories and Files organized into directories and subdirectories (folders in Windows)subdirectories (folders in Windows)

Exact location of file called its pathExact location of file called its path Anything not in directories is in the root Anything not in directories is in the root

directorydirectory

3 Main Files of DOS THESE FILES MUST BE ON COMPUTER OR IT THESE FILES MUST BE ON COMPUTER OR IT

WON’T BOOT!WON’T BOOT!– IO.SYS- handles talking to BIOS and hardwareIO.SYS- handles talking to BIOS and hardware– MSDOS.SYS-primary DOS code, the kernelMSDOS.SYS-primary DOS code, the kernel– COMMAND.COM-interprets commands, called COMMAND.COM-interprets commands, called

command interpreter, displays DOS promptcommand interpreter, displays DOS prompt These files not interchangeable on different versions These files not interchangeable on different versions

of DOSof DOS

DOS commands

ATTRIB- changes attributes to either ATTRIB- changes attributes to either read, system, hidden or archiveread, system, hidden or archive

DELTREE-deletes a directory and its DELTREE-deletes a directory and its subdirectory and all their filessubdirectory and all their files

CD- changes directoryCD- changes directory MD- creates directoryMD- creates directory DIR/W- to see files in wide formatDIR/W- to see files in wide format

MORE DOS

Wildcards- use a * to find all files with Wildcards- use a * to find all files with similar text, example- *.com to find all similar text, example- *.com to find all files that end in .com. The ? Symbol files that end in .com. The ? Symbol can be used to find matches for can be used to find matches for individual charactersindividual characters

Deleting- done with the DEL or ERASE Deleting- done with the DEL or ERASE commandscommands

Copying- COPYCopying- COPY Moving- MOVEMoving- MOVE

Config.sys in DOS

Following found in Config.sys used in DOS for – device drivers– buffers= statement (buffers are a

temporary assembly area for files in memory)

– stacks= statement allows CPU to set aside registers

– files= statement how many file handles

Sample CONFIG.SYS fileDevice=C:\DOS\HIMEM.SYS

Device=C:\DOS\EMM386.EXE 1024 RAM

FILES=30

BUFFERS=15

STACKS=64,500

DEVICE=C:\DOS\SMARTDRV.SYS 1024

DOS=HIGH, UMB

DEVICEHIGH=C:\MOUSE\MOUSE.SYS

DEVICEHIGH=C:\DOS\RAMDRIVE.SYS 4096/a

AUTOEXEC.BAT

Another way to support devices is through Another way to support devices is through TSR’s (terminate and stay resident) TSR’s (terminate and stay resident) programs. These are located in Autoexec.bat. programs. These are located in Autoexec.bat. One of the most common TSR’s is for miceOne of the most common TSR’s is for mice

DOSKEY.COM- is a TSR that keeps track of DOSKEY.COM- is a TSR that keeps track of commandscommands

MODE command changes look of monitorMODE command changes look of monitor SHARE command prevents file from being SHARE command prevents file from being

used by more than one programused by more than one program

DOS commands

SET command creates environmental SET command creates environmental variables so DOS programs can read variables so DOS programs can read themthem

PATH- command tells user where to PATH- command tells user where to look for file when not foundlook for file when not found

PROMPT- determines what prompt PROMPT- determines what prompt looks likelooks like

Using Commands for Drives in DOS

FDISK- partitioningFDISK- partitioning FORMAT- high level formatFORMAT- high level format VOL- see the volume label of driveVOL- see the volume label of drive SYS- copies 3 system files to partition making SYS- copies 3 system files to partition making

it bootable. Can make bootable floppies with it bootable. Can make bootable floppies with itit

LASTDRIVE- allows for memory allocation LASTDRIVE- allows for memory allocation beyond the 2 extra drive letters beyond Cbeyond the 2 extra drive letters beyond C

Checking Drives

CHKDSK- identifies and repairs lost cluster CHKDSK- identifies and repairs lost cluster chains. Will identify but not repair cross linked chains. Will identify but not repair cross linked files (2 files trying to claim same cluster)files (2 files trying to claim same cluster)

SCANDISK- repairs lost clusters, cross linked SCANDISK- repairs lost clusters, cross linked files, directory and file structures, file files, directory and file structures, file allocation tables, even volume labelsallocation tables, even volume labels

DEFRAG-DEFRAG-

Smartdrv

Initiated from the autoexec.bat fileInitiated from the autoexec.bat file Is a software disk cacheIs a software disk cache When run with /s will tell you efficiencly When run with /s will tell you efficiencly

of disk cacheof disk cache Page 558 and 559 gives possible Page 558 and 559 gives possible

command combinationscommand combinations