MS-DOS.

[NT 60487] Overview

[NT 60478] Works:	2 [NT 60520] works in 2 [NT 60521] publications in 1 [NT 60522] languages

[NT 60480] Titles

DOS 5 : a developer's guide; advanced programming guide to DOS [NT 59711] by: Williams, Al ([NT 1579] Language materials, printed)

DOS 5 user's guide : a comprehensive guide for every PC user [NT 59711] by: Gookin, Dan ([NT 1579] Language materials, printed)