VisiCalc 1.0 ("Visible Calculator") was the very first spreadsheet computer program for personal computers, invented by Dan Bricklin and originally released for the Apple II in 1979. It was ported to DOS in 1981 and is considered the killer app that turned the microcomputer from a hobby for computer enthusiasts into a serious business tool, prompting IBM to introduce the IBM PC two years later. More than 700,000 copies were sold in six years, and up to 1 million copies over its history.
Microsoft Word denotes a word processing program that is by far the most widely used wordprocessor in the world. It was initially introduced in 1983 as a multi-tool for the Xenix platform, and subsequently ported to PC DOS/MS-DOS of the IBM PC (1983) and compatible computers. Word is now part of the Microsoft Office suite.
dBase (also stylized dBASE) was the most successful database management system for microcomputers in its day. Originally released as Vulcan for PTDOS in 1978, the CP/M port caught the attention of Ashton-Tate in 1980. They licensed it and re-released it as dBASE II, and later ported it to IBM PC computers running MSDOS. On the PC platform, in particular, dBase became one of the best-selling software titles for a number of years.
QBASIC (Microsoft Quick Beginners All purpose Symbolic Instruction Code) was an IDE and interpreter for a variant of the BASIC programming language. For its time (1991), QBasic provided a state-of-the-art IDE, including a debugger with features such as on-the-fly expression evaluation and code modification. The game Gorillas was written in QBASIC.
Borland Turbo Pascal is an abandoned IDE for the programming language Pascal, developed and released by Borland Software Corporation in 1983. It ran on CP/M, CP/M-86, and DOS and was notable for its extremely fast compilation. Borland has released three old versions of Turbo Pascal free of charge because of their historical interest: the original Turbo Pascal (now known as 1.0), and versions 3.02 and 5.5 for DOS.
Norton Commander was a file manager and editor application first released 1986 by Peter Norton Computing for DOS. Norton Commander used a text-based user interface with side-by-side panels and featured copy, delete, editing and preview any kind of file easily: it was a vast improvement over the command-line only MS-DOS interface.
I-Ching is a really usable, attractive I-Ching software for DOS, and it WAS released as shareware originally. It is freeware now. This version of ICHING started out to be a translation of a CP/M program written in 1984 and has grown far beyond that. It is half Microsoft QuickBASIC and half assembly language. Requires DOSBox and DOSPanel to run under Windows10.