MS-DOS 1.40

According to MS-DOS 2.11 source code, MS-DOS 1.40 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 it will differ significantly from the previous MS-DOS 1.25 release. Tree structured directory (folder) support was first implemented in this build resulting it being closer to MS-DOS 2.00 than MS-DOS 1.25. 4 new internal commands (, ,   and  ) were added to the command interpreter (COMMAND.COM). The command interpreter reports version 1.20 upon boot.

Change log
1.40 06/15/82 Tree structured directories. XENIX Path Parser MKDIR CHDIR RMDIR Xenix calls