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Disk Contents of the
IBM® Personal Computer™ DOS
Version 1.10 (1982)


Copyright © 2005 by Daniel B. Sedory

NOT to be reproduced in any form without Permission of the Author !



DISK STRUCTURE

There were no changes since version 1.00. See our Disk Structure Table for 1.00.
IBM® Personal Computer™ DOS 1.10 was distributed on the same diskette type as the original: 160 KiB (163,840 bytes) divided into 40 tracks of only 8 SPT (sectors per track) for a total of 320 sectors on only 1 side of the diskette.

DISK CONTENTS

See our Tech Notes for DOS 1.00 on the difficulty of working with versions 1.10 and 1.00 of IBM®'s Personal Computer™ DOS; most notably, that you may not be able to use any other versions of DOS to copy files from these early diskettes unless the BIOS supports them. You can, however, still read the Directory under all later DOS versions [except in a Windows DOS-box] using the dir /a or dir /a:h commands (thus data about its two Hidden System files can be viewed when using much later versions of DOS):

 Volume in drive A has no label
 Directory of A:\

   File Name         Size    Allocated     Modified       Attrib

 IBMBIO   COM       1,920      2,048    05-07-82 12:00p     HS
 IBMDOS   COM       6,400      6,656    05-07-82 12:00p     HS
 COMMAND  COM       4,959      5,120    05-07-82 12:00p
 FORMAT   COM       3,816      4,096    05-07-82 12:00p
 CHKDSK   COM       1,720      2,048    05-07-82 12:00p
 SYS      COM         605      1,024    05-07-82 12:00p
 DISKCOPY COM       2,008      2,048    05-07-82 12:00p
 DISKCOMP COM       1,640      2,048    05-07-82 12:00p
 COMP     COM       1,649      2,048    05-07-82 12:00p
 EXE2BIN  EXE       1,280      1,536    05-07-82 12:00p
 MODE     COM       2,509      2,560    05-07-82 12:00p
 EDLIN    COM       2,392      2,560    05-07-82 12:00p
 DEBUG    COM       5,999      6,144    05-07-82 12:00p
 LINK     EXE      41,856     41,984    05-07-82 12:00p
 BASIC    COM      11,392     11,776    05-07-82 12:00p
 BASICA   COM      16,768     16,896    05-07-82 12:00p
 ART      BAS       1,920      2,048    05-07-82 12:00p
 SAMPLES  BAS       2,432      2,560    05-07-82 12:00p
 MORTGAGE BAS       6,272      6,656    05-07-82 12:00p
 COLORBAR BAS       1,536      1,536    05-07-82 12:00p
 CALENDAR BAS       3,840      4,096    05-07-82 12:00p
 MUSIC    BAS       8,704      8,704    05-07-82 12:00p
 DONKEY   BAS       3,584      3,584    05-07-82 12:00p
 CIRCLE   BAS       1,664      2,048    05-07-82 12:00p
 PIECHART BAS       2,304      2,560    05-07-82 12:00p
 SPACE    BAS       1,920      2,048    05-07-82 12:00p
 BALL     BAS       2,048      2,048    05-07-82 12:00p
 COMM     BAS       4,352      4,608    05-07-82 12:00p

       28 file(s)        147,489 bytes
         0 dir(s)        153,088 bytes allocated
                           7,168 bytes free
                         160,256 bytes total disk space,  95% in use

From our analysis of the disk's structure, we know there are only 160,256 bytes for the File area ("disk space" as seen in CHKDSK display above), because the Boot Record, FAT and Directory structures use 3,584 bytes of the disk's total capacity. We see above that 5% (or 7,168 bytes) of that space is left for user files. The diskette does in fact contain 163,840 bytes (160 KiB) of accessible data.

Location of Files on Diskette

By forcing a disk editor to use its "Physical" (vs. "Logical") view of the diskette, we were able to discover the physical location of each file as follows [Note: Most system utility programs, such as WinHex, will not recognize this diskette nor its image file, so we've added a column showing the Absolute Sector location for the beginning of each file. Absolute Sector = Cluster + 5 ]:

 Absolute Sector 3
 -----------------                                  Absolute
   Name   .Ext    Size    Date      Time    Cluster Sector   A R S H D V

  IBMBIO   COM    1920   5-07-82  12:00 pm       2      7    - - S H - -
  IBMDOS   COM    6400   5-07-82  12:00 pm       6     11    - - S H - -
  COMMAND  COM    4959   5-07-82  12:00 pm      19     24
  FORMAT   COM    3816   5-07-82  12:00 pm      29     34
  CHKDSK   COM    1720   5-07-82  12:00 pm      37     42
  SYS      COM     605   5-07-82  12:00 pm      41     46
  DISKCOPY COM    2008   5-07-82  12:00 pm      43     48
  DISKCOMP COM    1640   5-07-82  12:00 pm      47     52
  COMP     COM    1649   5-07-82  12:00 pm      51     56
  EXE2BIN  EXE    1280   5-07-82  12:00 pm      55     60
  MODE     COM    2509   5-07-82  12:00 pm      58     63
  EDLIN    COM    2392   5-07-82  12:00 pm      63     68
  DEBUG    COM    5999   5-07-82  12:00 pm      68     73
  LINK     EXE   41856   5-07-82  12:00 pm      80     85
  BASIC    COM   11392   5-07-82  12:00 pm     162    167
  BASICA   COM   16768   5-07-82  12:00 pm     185    190

 Absolute Sector 4
 -----------------
  ART      BAS    1920   5-07-82  12:00 pm     218    223
  SAMPLES  BAS    2432   5-07-82  12:00 pm     222    227
  MORTGAGE BAS    6272   5-07-82  12:00 pm     227    232
  COLORBAR BAS    1536   5-07-82  12:00 pm     240    245
  CALENDAR BAS    3840   5-07-82  12:00 pm     243    248
  MUSIC    BAS    8704   5-07-82  12:00 pm     251    256
  DONKEY   BAS    3584   5-07-82  12:00 pm     268    273
  CIRCLE   BAS    1664   5-07-82  12:00 pm     275    280
  PIECHART BAS    2304   5-07-82  12:00 pm     279    284
  SPACE    BAS    1920   5-07-82  12:00 pm     284    289
  BALL     BAS    2048   5-07-82  12:00 pm     288    293
  COMM     BAS    4352   5-07-82  12:00 pm     292    297

  Last used cluster/sector on diskette:        300    305

  Unused sectors at end of diskette = 14
(14 sectors x 512 bytes/sector = 7,168 bytes free space).

MD5 Sums for every File on the Diskette

For a complete introduction to using MD5 Sums (click here).
If you believe that one or more of the files on your DOS version 1.10 diskette have become corrupted, compare their MD5 sums with this listing:


  05b9205ee6fa56cecbc5bf22b5b34555     IBMBIO.COM
  4cf27775844f90c7d4b615131dc9d0e5     IBMDOS.COM
  f95a073439e1ee7c9b0c9d37d42de7fe    COMMAND.COM
  31b9c8001d7e9d9e98808b93badf4b98     FORMAT.COM
  23424d1ee8fd418f5c770457439dcab2     CHKDSK.COM
  f4759b60f3a5fb8b8323ced9b2437e5a        SYS.COM
  aa465c0204b780ad73572c2220f7c231   DISKCOPY.COM
  b58414f95b22b95d0fa36a7314a75536   DISKCOMP.COM
  d2e84db1228b4371202bd3a81e19c51a       COMP.COM
  97d848f6216dfb22428793e8f09877ff    EXE2BIN.EXE
  08f99d509a3b6855ea992f3f7af0e6e7       MODE.COM
  78f7965a01690258f57abb89fa9e6f3c      EDLIN.COM
  e35e225c5fd5ada608c72fe17ccad0cf      DEBUG.COM
  b9103931cd3d05aad7f76bab57cae6f0       LINK.EXE
  5bb691f37298f553e0ca933d23cbb5a5      BASIC.COM
  a06e6df77c54d2b13506a2ba41e70518     BASICA.COM
  a1ab28c1e54ec1647eebe021c7a2b2ba        ART.BAS
  10dbd8e1c0276930e1a113e513da235d    SAMPLES.BAS
  c5f9ba1c20ff07291d0dc37f80a4bb56   MORTGAGE.BAS
  5d2b5c4979806d5d2d83bc04a4fbcedb   COLORBAR.BAS
  ada93f706eee602187298c37636e278f   CALENDAR.BAS
  488cd80e721ab7c18b60132f505aa0cb      MUSIC.BAS
  e09be04b3a7635cdb8671b36596b58e5     DONKEY.BAS
  a9ca3dddb9302af9d67ed20da440ba0d     CIRCLE.BAS
  f97480c4398dd5eca5f6ab029ac0c134   PIECHART.BAS
  8b44decbc81ae291a964a2063820e286      SPACE.BAS
  d6e5631740f25e6f4bebe2742f385775       BALL.BAS
  ee431c39b050784d192d0b530b431404       COMM.BAS

On our DOS 1.00 Forensic Examination page, we've also included the MD5 hash for an image file of the whole diskette! (Note: There's at least one other image file floating around the Net that differs from the one we copied directly from an actual DOS 1.10 diskette by only two bytes in the Directory area; but it takes only a 1-bit difference for the whole diskette to have a much different MD5 hash value! So even though every file above will match those from the other image file, it's hash value is is completely different than our MD5 hash.)

 

NOTE: This is still a work in progress!

 


 

Last Update: 13 August 2008 (13-08-2008).

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