PCjs Machines

Home of the original IBM PC emulator for browsers.

Microsoft MS-DOS 3.31

It’s unclear where this June 1989 release of MS-DOS 3.31 fits in the MS-DOS timeline, because it comes after MS-DOS 4.00 (October 1988) and MS-DOS 4.01 (April 1989). Note that COMPAQ MS-DOS 3.31 existed as early as September 1987, raising the question of whether there were earlier releases of Microsoft MS-DOS 3.31 as well.

Even though the majority of the files are dated June 1989, most of the copyright strings are unchanged from MS-DOS 3.30:

Microsoft(R) MS-DOS(R)  Version 3.31                                            
             (C)Copyright Microsoft Corp 1981-1987                              

Many of the utilities, such as TREE.COM, contain strings suggesting they are unchanged from MS-DOS 3.30:

The MS-Dos Directory Path Display Utility
(C)Copyright Microsoft Corp 1987
Version 3.30

and indeed, with the exception of a one-byte difference in the utility’s DOS version check, the 3.30 and 3.31 TREE.COM binaries are identical.

[PCjs Machine "ibm5170-msdos331"]

Waiting for machine "ibm5170-msdos331" to load....

Directory of MS-DOS 3.31 (1.44M Disk)

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

IO       SYS*    23581   6-14-89  12:07p
MSDOS    SYS*    30672   6-11-89   4:33p
COMMAND  COM     25276   6-01-89
4201     CPI     17089   6-01-89
5202     CPI       459   6-01-89
ANSI     SYS      1647   6-01-89
APPEND   EXE      5794   6-01-89
ASSIGN   COM      1530   6-01-89
ATTRIB   EXE     10656   6-01-89
BACKUP   COM     29976   6-19-89  12:29p
CHKDSK   COM     11867   6-01-89
COMP     COM      4183   6-01-89
COUNTRY  SYS     11254   6-01-89
DATACOPY EXE     27313   5-25-89   2:34p
DEBUG    COM     15944   6-01-89
DISKCOMP COM      5848   6-01-89
DISKCOPY COM      6264   6-01-89
DISPLAY  SYS     11259   6-01-89
DRIVER   SYS      1165   6-01-89
EDLIN    COM      7495   6-01-89
EGA      CPI     49065   6-01-89
EXE2BIN  EXE      3050   6-01-89
FASTOPEN EXE      3888   6-01-89
FC       EXE     15974   6-01-89
FDISK    COM     53275   6-01-89
FIND     EXE      6403   6-01-89
FORMAT   COM     19683   6-29-89  12:02p
GRAFTABL COM      6216   6-01-89
GRAPHICS COM     13943   6-01-89
GWBASIC  EXE     80592   6-01-89
JOIN     EXE      9612   6-01-89
KEYB     COM      9041   6-01-89
KEYBOARD SYS     19735   6-01-89
LABEL    COM      2346   6-01-89
LINK     EXE     39172   6-01-89
MCONFIG  COM      1361   3-27-89  10:09a
MODE     COM     15440   6-01-89
MORE     COM       282   6-01-89
NLSFUNC  EXE      3029   6-01-89
PRINT    COM      8995   6-01-89
PRINTER  SYS     13559   6-01-89
PROTO    SYS        54  12-06-88  10:50a
RAMDRIVE SYS      8225   6-01-89
READPORT COM        39  10-27-88   8:34p
REBOOT   COM        42  11-03-88   6:38a
RECOVER  COM      5281   6-01-89
REPLACE  EXE     13234   6-01-89
RESTORE  COM     35650   6-01-89
SELECT   COM      4132   6-01-89
SETCMOS  COM        96  11-10-88   2:29a
SETPORT  COM        24  12-09-88   7:02p
SETSPD   COM       151  10-14-88   2:49p
SETUP    COM        14  10-20-88   4:18p
SHARE    EXE      8608   6-01-89
SORT     EXE      1946   6-19-89  12:30p
SUBST    EXE     10552   6-01-89
SYS      COM      6127   6-01-89
TREE     COM      3540   6-01-89
UPDCFG   COM      7943  11-20-87   3:24p
XCOPY    EXE     11216   6-01-89
       60 file(s)     740807 bytes
                      700928 bytes free

NOTE: Like most of the directory listings PCjs provides, the above listing was generated by the PCjs DiskImage utility, but it is essentially identical to output from the MS-DOS DIR command. In both cases, no times are displayed for most of the files.

This is because those files have a 0x0000 timestamp, which technically is equivalent to midnight, but early versions of DOS treated zero as an uninitialized timestamp. On previous distribution disks, Microsoft used a timestamp of 0x0001 (two seconds past midnight) to indicate 12:00am, so this is just another indication that perhaps this was not a fully baked retail release.

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

COMMAND  COM    25276   6-01-89
4201     CPI    17089   6-01-89
5202     CPI      459   6-01-89
ANSI     SYS     1647   6-01-89
APPEND   EXE     5794   6-01-89
ASSIGN   COM     1530   6-01-89
ATTRIB   EXE    10656   6-01-89
BACKUP   COM    29976   6-19-89  12:29p
CHKDSK   COM    11867   6-01-89
COMP     COM     4183   6-01-89
COUNTRY  SYS    11254   6-01-89
DATACOPY EXE    27313   5-25-89   2:34p
DEBUG    COM    15944   6-01-89
DISKCOMP COM     5848   6-01-89
DISKCOPY COM     6264   6-01-89
DISPLAY  SYS    11259   6-01-89
DRIVER   SYS     1165   6-01-89
EDLIN    COM     7495   6-01-89
EGA      CPI    49065   6-01-89
EXE2BIN  EXE     3050   6-01-89
FASTOPEN EXE     3888   6-01-89
FC       EXE    15974   6-01-89
FDISK    COM    53275   6-01-89
FIND     EXE     6403   6-01-89
FORMAT   COM    19683   6-29-89  12:02p
GRAFTABL COM     6216   6-01-89
GRAPHICS COM    13943   6-01-89
GWBASIC  EXE    80592   6-01-89
JOIN     EXE     9612   6-01-89
KEYB     COM     9041   6-01-89
KEYBOARD SYS    19735   6-01-89
LABEL    COM     2346   6-01-89
LINK     EXE    39172   6-01-89
MCONFIG  COM     1361   3-27-89  10:09a
MODE     COM    15440   6-01-89
MORE     COM      282   6-01-89
NLSFUNC  EXE     3029   6-01-89
PRINT    COM     8995   6-01-89
PRINTER  SYS    13559   6-01-89
PROTO    SYS       54  12-06-88  10:50a
RAMDRIVE SYS     8225   6-01-89
READPORT COM       39  10-27-88   8:34p
REBOOT   COM       42  11-03-88   6:38a
RECOVER  COM     5281   6-01-89
REPLACE  EXE    13234   6-01-89
RESTORE  COM    35650   6-01-89
SELECT   COM     4132   6-01-89
SETCMOS  COM       96  11-10-88   2:29a
SETPORT  COM       24  12-09-88   7:02p
SETSPD   COM      151  10-14-88   2:49p
SETUP    COM       14  10-20-88   4:18p
SHARE    EXE     8608   6-01-89
SORT     EXE     1946   6-19-89  12:30p
SUBST    EXE    10552   6-01-89
SYS      COM     6127   6-01-89
TREE     COM     3540   6-01-89
UPDCFG   COM     7943  11-20-87   3:24p
XCOPY    EXE    11216   6-01-89
       58 File(s)    700928 bytes free

[GitHub Source]