The BASICA development environment was very similar to the integrated development environment used by Dartmouth BASIC. The user was given a prompt for entering program instructions. Statements beginning with a line number were inserted into the user's program at the appropriate position so that the statements would execute in numerical order at run-time. Statements which did not contain a line number were interpreted immediately at design-time. Some commands were intended to be used at run-time (such as LET, INPUT, WHILE and FOR) while others were intended to be used at design-time (such as SAVE, LOAD, NEW and RUN) but BASICA did not enforce these restrictions.
The following is an example of a session with BASICA:
The IBM Personal Computer Basic Version A2.00 Copyright IBM Corp. 1981, 1982, 1983
Ready. > list
Ready. > 10 print "please type your name"
Ready. > 20 input a$
Ready. > 30 for t = 1 to 10
Ready. > 40 print "hello "; a$;
Ready. > 50 next t
Ready. > 60 print a$; " you have "; str$(len(a$)); " letters in your name!"
Ready. > run please type you name john hancock hello john hancockjohn hancockjohn hancockjohn hancockjohn hancockjohn hancockjohn hancockjohn hancockjohn hancockjohn hancockjohn hancock yo u have 12 letters in your name!
Ready. > system
Successors A similar BASIC interpreter was Microsoft GW-BASIC that shipped with MS-DOS and didn't rely on the embedded ROM BASIC interpreter. Eventually IBM and other PC clone manufacturers removed ROM BASIC from the BIOS to make room on the small chip for more advanced features such as Plug and Play and Advanced power management[?]. In 1983 GW-BASIC was replaced with an even more advanced product from Microsoft called QuickBASIC. While Microsoft sold QuickBASIC separately from DOS, a subset of the language called QBASIC continued to be included with DOS and later Microsoft Windows.
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