After the initial success of Altair BASIC, Microsoft BASIC became the basis for a lucrative software licensing business, being ported to the majority of the numerous
home and other
personal computers of the 1970s and especially the 1980s, and extended along the way. Contrary to the original Altair BASIC, most home computer BASICs are resident in
ROM, and thus are available on the machines at power-on in the form of the characteristic "READY". prompt. Hence, Microsoft's and other variants of BASIC constitute a significant and visible part of the
user interface of many home computers' rudimentary
operating systems. Microsoft used its
DECsystem-20 to produce assembly code for dozens of different computer systems and CPUs from the same
source code, using
conditional compilation. By 1981, Microsoft BASIC was so popular that even companies that already had a BASIC licensed the language, such as
IBM for its
Personal Computer, and
Atari, which sold both
Atari Microsoft BASIC and its own
Atari BASIC. IBM's
Don Estridge said, "Microsoft BASIC had hundreds of thousands of users around the world. How are you going to argue with that?" Microsoft licensed similar versions to companies that competed with each other. After licensing
IBM Advanced BASIC (BASICA) to IBM, for example, Microsoft licensed the compatible
GW-BASIC to makers of
PC clones, and sold copies to retail customers. The company similarly licensed an
Applesoft-compatible BASIC to
VTech for its
Laser 128 clone.
Extended BASIC-80 •
Tangerine Microtan 65 •
Spectravideo SV-318 and
SV-328 Known variants: •
NCR Basic Plus 6, released in the first quarter of 1977 for the
NCR 7200 model VI data-entry terminal. The adaptation of Microsoft's Extended BASIC-80 was carried out by
Marc McDonald in 1976/1977.
Disk BASIC-80 MBASIC is available for
CP/M-80 and
ISIS-II. Also available for
TEKDOS. MBASIC is a stripped-down BASIC-80 with only hardware-neutral functions. However, due to the popularity of CP/M, the great majority of Z80 machines ran MBASIC, rather than a version customized for specific hardware (TRS-80 BASIC was one of the few exceptions). Microsoft's CP/M card for the Apple II included a modified version of MBASIC that incorporated some of the graphics commands from Applesoft BASIC, such as HPLOT, but the full command set is not supported.
Standalone Disk BASIC-80 The first implementation to use an
8-bit variant of the
File Allocation Table (FAT) was a BASIC adaptation
TRS-80 Level II/III BASIC The TRS-80 computer was offered initially with an adaption of Li-Chen Wang's
Tiny BASIC (
Level I BASIC); within a few months this was replaced by a port of BASIC-80 which incorporated some of Level I BASIC's command set, particularly the commands for setting graphics characters. Level II BASIC contained some of the features of Extended BASIC, although due to the need to include Level I commands such as SET and PSET, other features such as descriptive error messages still had to be left out; these were subsequently added into TRS-80 Disk BASIC. The TRS-80 Model 4 had a newer disk-based BASIC that used the BASIC-80 5.x core, which included support for 40-character variable names. Thus the ability to crunch program lines (without spaces between keywords and arguments) was no longer possible as it had been in Level II. It was no longer necessary to reserve string space. New features included user defined functions (DEF FN) and access to TRSDOS 6 system functions via a SYSTEM keyword. A modified version published later by OS provider Logical Systems, in the LS-DOS Version 6.3 update, added single-letter access to BASIC control functions (like LIST and EDIT) and direct access to LS-DOS supervisor calls. The program edit environment was still line-oriented. The facility available in Level II to sort arrays (CMD"O") was not available; programmers and users had to devise their own workarounds.
BASIC-86 The first implementation as a standalone disk-based language system was for
Seattle Computer Products S-100 bus 8086 CPU card in 1979. It was using an
8-bit FAT file system. Microsoft also offered a version of Standalone BASIC-86 for SBC-86/12 for Intel's 8086
Single Board Computer platform in 1980.
6502 BASIC Microsoft ported BASIC-80 to the 6502 during the summer of 1976; it was mostly a straight port of the 8K version of BASIC-80 and included the same prompts asking for memory size and if the user wanted floating point functions enabled or not (having them active used an extra 135 bytes of memory). The earliest machines to use 6502 BASIC were the
Ohio Scientific Model 500 and
KIM-1 in 1977. 6502 BASIC included certain features from Extended BASIC such as user-defined functions and descriptive error messages, but omitted other features like double precision variables and the PRINT USING statement. As compensation for not having double precision variables, Microsoft included 40-bit floating point support instead of BASIC-80's 32-bit floating point and string allocation was dynamic (thus the user did not have to reserve string space like in BASIC-80). However, vendors could still request BASIC with 32-bit floating point for a slightly smaller
memory footprint; as one example, Disk BASIC for the Atari 8-bits used 32-bit floating point rather than 40-bit. Standard features of the 9K version of Microsoft 6502 BASIC included: • GET statement to detect a key press. • Line crunching program lines do not require any spaces except between the line number and statement. • Only supported variable types are character string, single precision floating point, and 16-bit signed integer (saves space in arrays, otherwise useless and slower than floating point, as all calculations are done in floating point anyway). • Long variable names can be used, but only the first two characters are significant. • Dynamic string allocation. 6502 BASIC lacked a standardized set of commands for disk and printer output; these were up to the vendor to add and varied widely with each implementation. Later implementations of 6502 BASIC (1983–) had many vendor specific improvements; for example later versions of Commodore BASIC had the following: • Disk commands (DIRECTORY, DSAVE, DLOAD, BACKUP, HEADER, SCRATCH, COLLECT, DVERIFY, COPY, DELETE, RENAME, etc.) • Graphics commands (CIRCLE, DRAW, BOX, COLOR (of background, border, etc.), PAINT, SCALE) • Graphics block copy and logical operation with the existing graphical screen (SSHAPE and GSHAPE with OR, AND, XOR, etc.) • Sprite definition, displaying and animation commands on C128, even saving sprites to binaries • Sound commands (VOL, SOUND), later on at C=128 Music commands (ADSR and SID filter programming (ENVELOPE and FILTER), PLAY, TEMPO commands) • Signs of more structured programming: IF–THEN–ELSE, DO–LOOP–WHILE/UNTIL–EXIT. • Extended I/O commands for special features: JOY, function keys • Debugging commands: STOP, CONT, TRON, TROFF, RESUME • Extended handling of character screen: WINDOW • Support easier program development: RENUMBER, NEW, MONITOR, RREG
BASIC-68 and BASIC-69 Microsoft catalogs from the 1980s also showed the availability of BASIC-68 and BASIC-69 for the
Motorola 6800 and
6809 microprocessors respectively, running the
FLEX operating systems, and also mention OEM versions for
Perkin-Elmer,
Ohio Nuclear,
Pertec and
Societe Occitane d'Electronique systems. It seems likely this is what is also the basis for the Microsoft/Epson BASIC in the
Epson HX-20 portable computer, which has two Hitachi 6301 CPUs, which are essentially a "souped up" 6801. Most of the core features in BASIC-68 and BASIC-69 were copied directly from BASIC-80. BASIC-69 was notably also licensed to Tandy, where it formed the nucleus of
Color BASIC on the
TRS-80 Color Computer. Not to be confused with
BASIC09, a very different BASIC created by
Microware as the main language for its
OS-9, the other OS available on the Color Computer (Microware also wrote version 2.0 of Extended Color BASIC when Microsoft refused to do it). Microsoft BASIC was also included in the Dragon 32 / 64 computers that were built in Wales and enjoyed some limited success in the UK home computer market in the early 1980s. Dragon computers were mostly compatible with the Color Computer, as they were built on very similar hardware.
MSX Microsoft produced a ROM-based
MSX BASIC for use in
MSX home computers, which used a Z80 processor. This version supported the graphics and sound systems of the MSX computers; some variants also had support for disk drives. == Modern descendants ==