MS-DOS 1.54

According to the MS-DOS 2.11 source code, MS-DOS 1.54 is an unreleased internal version of MS-DOS. At this stage of development, it is already clear that the next major release of MS-DOS is version MS-DOS 2.00 and that it will differ significantly from the previous MS-DOS 1.25 release.

Change log
1.54 07/11/82 Function calls 1-12 make use of new 2.0 PDB. Init code changed to set file handle environment.