IBM DOS Version 4.01


Labels used with permission of IBM® Corporation
Labels copyright © IBM® Corporation

Boot Screen:


Copyright © IBM® Corporation
As you see here, the SELECT boot screen is identified as 4.00 (this IS the actual 4.01 screen). This is no accident. IBM shipped 4.01 without changing the version IDs, either in the kernel, the command processor, or within the documentation. Refer to the bottom of this page for a complete review that covers the circumstances and the actual changes.

Package Contents:

Package images used with permission
IBM® Corporation
Outer Cover (Cardstock), P/N: 6280256
Inner Box (Cardstock), no P/N: printed
White styrofoam block
Diskette Envelope, P/N:64F5190
Getting Started Guide, P/N: 84F7648
DOS Shell Reference Card, P/N: 15F1374
Proof of License, P/N:15F1375
License Information Pamphlet, P/N:15F1376
Keyboard Layout order card (insert), P/N:64F5017
User Manual, P/N: 84F7649
Install Diskette, P/N: 15F1477
Operating Diskette, P/N: 15F

Collector's notes:
Rated: Mildly Rare.
Estimated Value (complete): Mint-$75 VG-$50 G-$30

Vital Statistics:

Release Date: August, 1988
Disks in Set: 2
Diskette Form Factor:3.5", DS,DD 9 sectors per track
Capacity: 720k
Sector Size: 512 bytes
Sectors per cluster: 1
Reserved sectors: 1
Root directory entires: 112
Total sectors: 1440
Media descriptor: F9
Sectors per FAT: 5
Track Size: 9 sectors
Disk Sides: 2
Total Tracks: 80
File System: FAT12 floppy, FAT16 fixed disk
Files on Disk1: 36
Files on Disk 2: 40

Version String (Sector 04F, offset E0h):



49 42 4D 20 44 4F 53 20 56 65 72 73 69 6F 6E 20 ¦ IBM DOS Version

34 2E 30 30 20 28 43 29 43 6F 70 79 72 69 67 68 ¦ 4.00 (C)Copyrigh

74 20 49 42 4D 20 43 6F 72 70 20 31 39 38 31 2C ¦ t IBM Corp 1981,

31 39 38 38 4C 69 63 65 6E 73 65 64 20 4D 61 74 ¦ 1988Licensed Mat

65 72 69 61 6C 20 2D 20 50 72 6F 67 72 61 6D 20 ¦ erial - Program

50 72 6F 70 65 72 74 79 20 6F 66 20 49 42 4D 4E ¦ Property of IBM


File Listing:

Disk 1 Install: 08/03/1988 12:00p 32,816 IBMBIO.COM 08/03/1988 12:00p 36,000 IBMDOS.COM 06/17/1988 12:00p 39 AUTOEXEC.BAT 06/17/1988 12:00p 9,148 ANSI.SYS 06/17/1988 12:00p 37,637 COMMAND.COM 06/17/1988 12:00p 96 CONFIG.SYS 06/17/1988 12:00p 12,838 COUNTRY.SYS 06/17/1988 12:00p 10,428 DISKCOPY.COM 06/17/1988 12:00p 15,741 DISPLAY.SYS 06/17/1988 12:00p 5,274 DRIVER.SYS 06/17/1988 12:00p 16,302 FASTOPEN.EXE 06/17/1988 12:00p 70,151 FDISK.COM 06/17/1988 12:00p 22,923 FORMAT.COM 08/03/1988 12:00p 21,653 IFSFUNC.EXE 06/17/1988 12:00p 14,759 KEYB.COM 08/03/1988 12:00p 23,360 KEYBOARD.SYS 08/03/1988 12:00p 23,056 MODE.COM 06/17/1988 12:00p 18,946 PRINTER.SYS 06/17/1988 12:00p 17,199 REPLACE.EXE 08/03/1988 12:00p 22,453 SELECT.DAT 08/03/1988 12:00p 99,545 SELECT.EXE 08/03/1988 12:00p 27,562 SELECT.HLP 08/03/1988 12:00p 1,594 SELECT.PRT 08/03/1988 12:00p 10,301 SHARE.EXE 06/17/1988 12:00p 11,472 SYS.COM 06/17/1988 12:00p 6,376 VDISK.SYS 06/17/1988 12:00p 17,087 XCOPY.EXE 08/03/1988 12:00p 29,249 XMA2EMS.SYS 06/17/1988 12:00p 19,312 XMAEM.SYS 06/17/1988 12:00p 49,052 EGA.CPI 06/17/1988 12:00p 10,592 LCD.CPI 06/17/1988 12:00p 6,404 4201.CPI 06/17/1988 12:00p 641 4208.CPI 06/17/1988 12:00p 402 5202.CPI 06/17/1988 12:00p 109 012345.678 06/17/1988 12:00p 0 DOS00I.40 36 File(s) 700,517 bytes 0 Dir(s) 17,408 bytes free 728,064 bytes total disk space. 69,632 bytes in 3 hidden files. 641,024 bytes in 33 files. 17,408 bytes available on disk. 512 bytes in each allocation unit. 1,422 total allocation units on disk. 34 allocation units available on disk. Disk 2 Operating: 08/03/1988 12:00p 11,186 APPEND.EXE 06/17/1988 12:00p 5,785 ASSIGN.COM 06/17/1988 12:00p 18,247 ATTRIB.EXE 06/17/1988 12:00p 33,754 BACKUP.COM 06/17/1988 12:00p 1,065 BASIC.COM 06/17/1988 12:00p 36,285 BASICA.COM 06/17/1988 12:00p 17,771 CHKDSK.COM 06/17/1988 12:00p 9,491 COMP.COM 06/17/1988 12:00p 21,606 DEBUG.COM 06/17/1988 12:00p 9,889 DISKCOMP.COM 06/17/1988 12:00p 6,660 DOSUTIL.MEU 06/17/1988 12:00p 14,249 EDLIN.COM 06/17/1988 12:00p 11,125 FILESYS.EXE 06/17/1988 12:00p 5,983 FIND.EXE 06/17/1988 12:00p 22,923 FORMAT.COM 06/17/1988 12:00p 10,271 GRAFTABL.COM 06/17/1988 12:00p 16,733 GRAPHICS.COM 06/17/1988 12:00p 9,413 GRAPHICS.PRO 06/17/1988 12:00p 17,457 JOIN.EXE 06/17/1988 12:00p 4,490 LABEL.COM 06/17/1988 12:00p 20,133 MEM.EXE 06/17/1988 12:00p 2,166 MORE.COM 06/17/1988 12:00p 6,207 MORTGAGE.BAS 06/17/1988 12:00p 6,910 NLSFUNC.EXE 06/17/1988 12:00p 295 PCIBMDRV.MOS 06/17/1988 12:00p 961 PCMSDRV.MOS 06/17/1988 12:00p 801 PCMSPDRV.MOS 08/03/1988 12:00p 14,024 PRINT.COM 06/17/1988 12:00p 10,732 RECOVER.COM 06/17/1988 12:00p 17,199 REPLACE.EXE 06/17/1988 12:00p 40,030 RESTORE.COM 06/17/1988 12:00p 4,438 SHELL.CLR 08/03/1988 12:00p 65,667 SHELL.HLP 08/03/1988 12:00p 4,588 SHELL.MEU 08/03/1988 12:00p 3,937 SHELLB.COM 08/03/1988 12:00p 154,377 SHELLC.EXE 06/17/1988 12:00p 5,914 SORT.EXE 06/17/1988 12:00p 18,143 SUBST.EXE 06/17/1988 12:00p 6,334 TREE.COM 06/17/1988 12:00p 0 DOS01L.400 40 File(s) 667,239 bytes 0 Dir(s) 51,200 bytes free 728,064 bytes total disk space. 0 bytes in 1 hidden files. 676,864 bytes in 39 files. 51,200 bytes available on disk. 512 bytes in each allocation unit. 1,422 total allocation units on disk. 100 allocation units available on disk.

MD5 Signatures:

IBMBIO COM 84AOF13B1AlOBD2971FB1531C706EAA0 IBMDOS COM F91BC37BF644696CDB6ESFA7795FF84F COMMAND COM 2007AD425C1DBOIFC226527243B8C8E7 VER command: IBM DOS Version 4.00

Version History:

Superceeds IBM DOS 4.00. For DOS collectors this version is a mystery at first glance. What's up with getting 4.01 in a box marked 4.00, with manuals marked 4.00, and a version I.D. at the command prompt marked 4.00? In the Spring of 1988, IBM decided to make a change of policy and develop their first major DOS release independent of Microsoft (possibly to brand it against the PS/2 line). When they released 4.00 in July, 1988 first to market, Microsoft found itself in a position where they were selling an IBM-developed DOS, which they released as MS-DOS 4.00 in the Fall of 1988.

Microsoft soon discovered, as did a number of IBM users, that DOS 4.00 had problems, most notably with the DOS Shell and memory management issues. IBM then hunted down the bugs and documented the problems in bulletin CSD-UR22624 (see bottom of this page). With the problems identified, IBM wrote the patches and released the update, both to Microsoft directly and to the public.

Here is where the confusion comes in. Microsoft clearly identified the update as "4.01". IBM, however, released it as "4.0" using the original 4.00 documentation, manuals, and packaging. Only the diskettes were clearly labeled, correctly marked "Version 4.01" (as seen at the top of this page) and containing the patched files. To add to the confusion, IBM released the 4.01 disks in two packages (both with 3.5" disks) - a large style binder pack with paper cover like the earlier 4.00 release, and a smaller, cardstock type box that became the standard packaging for the IBM 5.xx DOS releases. This page has the P/N:'s for the smaller package - the IBM DOS 4.00 page that preceeds this has the P/N:'s for the large one.

The following is the list of differences between 4.00 and 4.01. It should be noted that several other files were re-dated, but the file size did not change. This may indicate changes were made, with the code embedded in file white spaces. Only those files with recorded differences between the two versions are listed here. The IBM CSD bug list is also included:




Disk 1: Install

File	4.00	4.01		Change in bytes/

	06/88	08/88		Function of file

------------------------------------------------------

IBMBIO 	32,810	32,816	+6	BIOS

IBMDOS 	35,984	36,000	+16	Kernel

IFSFUNC	21,637	21,653	+16	Installable file system

MODE	23,040	23,056	+16	Display and Port control

SELECT	99,791	99,545	-246	OS Installation

SHARE	10,285	10,301	+16	File Sharing

XMA2EMS	29,236	29,249	+13	Expanded Memory Support

------------------------------

Total:	252783	252620

Difference:			-163 bytes in 4.01

Disk 2: Operating

------------------------------------------------------

APPEND	11,170	11,186	+16	Define search path

PRINT	14,163	14,024	-139	Print spooler

SHELL	66,977	65,667	-1310 	DOS Shell help file

SHELLC	153975	154377	+402	DOS Shell Control

------------------------------

Total:	246285	245254

Difference:			-1031 bytes in 4.01



IBM Official bug list - IBM DOS 4.00:



APPEND  APPEND /PATH:OFF not working properly

IBMBIO   INT 2FH for INT 67H causes hang

IBMDOS  BUFFERS=XX /X problem (BUFFERS to XMA)

IBMDOS  problem copying large files across NET

MODE     MODE overwrites user's application

MODE     MODE not handling trans. correctly

MODE     MODE allows 19200 rate on PS/2 mod 25,30

PRINT       First time PRINT non-exist file msg

SELECT    Listing of printers should be reordered

SELECT    SELECT correct defaults for keyboards

SELECT    Using CTRL/BREAK with SHELL can hang

SELECT    SELECT/SHELL translated too big for 256K

SHELL    PS/2 mod 30 with 8512 error color change

SHELLC    SHELL does not give error for / or \

SHELLC    SHIFT+F9=  overlays F10=

SHELLC    SHELL HELP index entries not alphabetic

SHELLC    SHELL place hdwr cursor with selection

SHELLC    Pull down menu in files gives wrong help

SHELLC    SHELL will not run after run Comp. BASIC

SHELLC    SHELL not handling trans. correctly

XMA2EMS  Unpredictable results using DMA to EMS

XMA2EMS  PS/2 mod 50Z cannot use DOS 4.00 EMS

XMA2EMS  Hangs with Token Ring NET CARD in slot 0