IBM PC DOS 4.00 (06-17-1988)
Released in 1988 by IBM
For IBM PC, XT, AT, and PS/2 computers

Image Quality: Unmodified

This is the original release of PC-DOS 4.00. Bugs and all!

IBM DOS 4.00 was IBM's first in-house development effort with DOS.
Prior to this release, all DOS code had been managed by Microsoft on
IBM's behalf (hence the parallel releases). With this version, IBM
re-engineered the source and added their own enhancements. PC-DOS
4.00 adds support for drives up to 2 gigabytes and a graphical DOS
shell. The initial release of IBM PC-DOS 4.00 was extremely buggy. It
was quickly followed up by a 4.01 update.

Note: The 4.01 update continued to ship with 4.00 documentation, 
identifies itself as "4.00", and used the same IBM part number. There 
are only two ways to tell the difference: The 4.01 update has some 
files dated 1988-08-03, and the printed disk label will say "4.01".

Archive includes two 3.5" 720k disk images.