Working in DOS DOS is a true operating system An operating system does 4 things: it must communicate with the hardware it must create a user interface must allow users to use and manage programs must allow users to add, move and delete the installed programs

DOS Until version 5.0 you could only get DOS on a PC and not off the shelf Memorize chart on page 520 Files in DOS- Filename no longer that 8 characters Extension up to 3 characters No spaces in filename or extension Cannot use /\[]<>+=;,*? REMEMBER WIN 95/98 DOES HAS 255 CHARACTER LIMIT

DOS DOS cannot support more than 2 floppy drives Files organized into directories and subdirectories (folders in Windows) Exact location of file called its path Anything not in directories is in the root directory

3 Main Files of DOS THESE FILES MUST BE ON COMPUTER OR IT WON’T BOOT! IO.SYS- handles talking to BIOS and hardware MSDOS.SYS-primary DOS code, the kernel COMMAND.COM-interprets commands, called command interpreter, displays DOS prompt These files not interchangeable on different versions of DOS

DOS commands ATTRIB- changes attributes to either read, system, hidden or archive DELTREE-deletes a directory and its subdirectory and all their files CD- changes directory MD- creates directory DIR/W- to see files in wide format

MORE DOS Wildcards- use a * to find all files with similar text, example- *.com to find all files that end in .com. The ? Symbol can be used to find matches for individual characters Deleting- done with the DEL or ERASE commands Copying- COPY Moving- 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 file Device=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 TSR’s (terminate and stay resident) programs. These are located in Autoexec.bat. One of the most common TSR’s is for mice DOSKEY.COM- is a TSR that keeps track of commands MODE command changes look of monitor SHARE command prevents file from being used by more than one program

DOS commands SET command creates environmental variables so DOS programs can read them PATH- command tells user where to look for file when not found PROMPT- determines what prompt looks like

Using Commands for Drives in DOS FDISK- partitioning FORMAT- high level format VOL- see the volume label of drive SYS- copies 3 system files to partition making it bootable. Can make bootable floppies with it LASTDRIVE- allows for memory allocation beyond the 2 extra drive letters beyond C

Checking Drives CHKDSK- identifies and repairs lost cluster chains. Will identify but not repair cross linked files (2 files trying to claim same cluster) SCANDISK- repairs lost clusters, cross linked files, directory and file structures, file allocation tables, even volume labels DEFRAG-

Smartdrv Initiated from the autoexec.bat file Is a software disk cache When run with /s will tell you efficiencly of disk cache Page 558 and 559 gives possible command combinations