MS-DOS-by-Temitope-Akanni-2003-ffuall.ppt

MS-DOS-by-Temitope-Akanni-2003-ffuall.ppt

1. MS-DOS/PC-DOS
by:
Temitope Akanni
CS550: Operating Systems
Fall 2003

2. CP/M
–Created by Gary Kildall
–Control Program for Microcomputers was
used to run floppy disk drive of IMSAI 8080
–Licensed from Digital Research
•Features from CP/M
–COM formats
–CP/M used CCP (Console Command
Processor) as a command interpreter
–BDOS and BIOS – handled system files and
I/O

3. QDOS
–Quick and Dirty Operating System, written
by Tim Patterson of Seattle Computer
Products to take advantage of the 16-bit Intel
8086 board
–QDOS became 86-DOS and then DOS
•Features from QDOS
–C:> prompt
–8 character file names with 3 character
extensions

4. DEVELOPMENT HISTORY
Date Version Release
August 12, 1981DOS 1.0 – IBM’s release
Used Patterson’s 86-DOS
May 1982 DOS 1.1
IBM’s release of DOS to handle new double-
sided drives
August 1982 DOS 1.25 Microsoft’s own release of DOS 1.1
March 1983 DOS 2.0 for IBM’s PC-XT
Support 10MB hard drives, 3-internal expansion
slots, hierarchical tree structure

5. DEVELOPMENTS cont.
Date Version Release
March 1984 DOS 2.1 IBM’s release
Handled hardware errors called PCjr
1984 DOS 2.11 Microsoft’s release
Added international time, date, currency, and
keyboard support.
1984 DOS 3.0 for IBM’s 16-bit PC-AT system
Support 1.2MB diskettes and hard drives over
10MB. Designed by Microsoft to support IBM
network hardware
November 1984 DOS 3.1
Provided better aliasing – made DOS treat
directories as drives. Handled network hardware

6. DEVELOPMENTS cont.
Date Version Release
January 1986 DOS 3.2
Introduced and provided support of 3-1/2
floppies and 720K disk
April 1987DOS 3.3 IBM’s release
FDISK can be used to create 32MB or smaller
logical drives from extended partitions
1987 DOS 3.30 Compaq’s release
Support 1.44MB diskettes and multiple 32MB
disk partitions
November
1987
DOS 3.31 Compaq’s release
Support drives greater than 32MB

7. Date Version Release
July 1988 DOS 4.0 IBM’s release
Added a DOS Shell interface and support for disk
partitions greater than 32MB. Provided support for
mouse and graphical interfaces.
November 1988DOS 4.01- Fixed bugs introduced in 4.0
June 1991 MS-DOS 5.0 Microsoft’s release
Allowed DOS to reside in area above 640K memory.
Provided support for loading device drivers. Provided
an improved DOS Shell
March 1993 DOS 6.0 Microsoft’s release
Introduced DoubleSpace disk compression
DEVELOPMENTS cont.

8. DEVELOPMENTS cont.
Date Version Release
November 1993DOS 6.2 Microsoft’s release
February 1994DOS 6.21 Microsoft’s release
Removed DoubleSpace disk compression
June 1994 DOS 6.22 Microsoft’s release
Introduced “DriveSpace” disk compression
April 1995 DOS 7.0 IBM’s release
August 1995DOS 7.0 Microsoft's release

9. •DOS is a single-tasking OS but DOS 2.0 allowed
users to print out files while working on another.
•OS/2 provided a multitasking environment.
TEMPORARY ENVIRONMENT
•DOS allows the user to specify a temporary command
processor (child process) with its own environment.
Change in child environment is not reflected in the
parent.
–C:> cmd /E:512
SINGLE TASKING

10. FILE MANAGEMENT
•Uses a multi-level hierarchical directory
structure
•FAT file contains the addresses of file
clusters to build data
•Some hard disks contain two copies of the
FAT file, which are updated when data
changes in a file

11. MEMORY MANAGEMENT
From: http://www.frick-cpa.com/dos/DOS_Memory_1.asp

12. MEMORY cont.
•Conventional Memory: User Memory from 0–
640Kb
•Expanded Memory: below 1024Kb of memory
•Extended Memory: 1024Kb or 1MB and above
•High Memory Area (HMA): The first 64Kb block
of memory in EMA
•Upper Memory (UMA): Memory located between
640K and 1024K

13. DISK DILEMMA
•Problem: Designers must decide the size of FAT
chart
–Standard diskette held: 160K
–IBM PC came with 16K of RAM
•Solution: Give FAT a maximum of 16-bit
address
–Largest table could have 64K entries
–64K entries * 512bytes/sector = 32MB
(Maximum size of hard disk)
–Created problem in accessing larger disks
drives

14. DISK MANAGEMENT
•Solutions to the 32MB hard disk problem
1.DOS 3.3 : FDISK
•Used to divide large physical memory into smaller
logical partitions of 32MB or less
2.Compaq’s DOS 3.31
•Extended DOS to hold 32-bit FAT address,
thereby allowing logical partitions of .5GB
3.DOS 4.0:
•Allowed large hard drives greater than 32MB

15. COMMANDS
•Internal
–Common commands found inside
COMMAND.COM, the command interpreter
BREAK CALL CD
CHCP MKDIR CHDIR
CLS COPY DATE
DEL DIR ECHO
ERASE EXIT FOR
GOTO IF PATH

16. Commands cont.
•External
–Separate programs outside of COMMAND.COM
–Commands are contained their own file
–PATH must be set for the commands
APPEND.EXE ASSIGN.COM ATTRIB.EXE
BACKUP.EXE CHKDSK.EXE COMP.EXE
DEBUG.EXE DISKCOMP.COM DISKCOPY.COM
DOSKEY.COM PRINT.EXE MORE.EXE

17. Internal/External: A Brief Exercise
•To check if a command is internal/external
–type: set path=
–format /?copy /? – these are internal commands
Example of an external command:
•D:\>doskey /?
•'doskey' is not recognized as an internal or external
command, operable program or batch file.
•Start another command session
–Don’t set the path to null
–Type doskey at the prompt
•Nothing happened, but the doskey executable
(DOSKEY.COM) was found and is running

18. FUTURE OF DOS
•Windows OSs and IBM OS/2 Warp can run
DOS applications but do not rely on it
•IBM has a PC-DOS 2000
•Caldera has an extended version of DOS
call DR-OpenDOS
•DOS will fizzle out but not for another
couple of years

19. REFERENCES
IBM. “PC DOS 2000.”
URL:http://www-3.ibm.com/software/os/dos/dos2
000/dos_qa.html
Somerson, Paul. DOS Power Tools. New York, NY:
Bantam Books. ISBN: 0-553-35464-7
Wolverton, Van. Running MS-DOS 20
th
Anniversary
Edition. Microsoft Press, 2002. ISBN: 0-7356-
1812-7.