Transcript Working in DOS

Working in DOS
DOS is a true operating system
 An operating system does 4 things:
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– 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 /\[]<>+=;,*?
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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
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3 Main Files of DOS
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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
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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
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Config.sys in DOS
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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
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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
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Using Commands for Drives in
DOS
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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
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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
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