The Altair BASICinterpreter was developed by Microsoft founders Paul Allen and Bill Gates with help from Monte Davidoff, using a self made Intel 8080 software simulator running on a PDP-10minicomputer. The dialect of BASIC was similar to Digital Equipment Corporation interpreters, especially in string operations, which varied between BASIC implementations. BASIC used dynamically allocated strings which stored their size. Early BASIC only supported single letter and digit names, but Microsoft BASIC supported long variable names. Only two characters were significant though; AD, ADDRESS1, and ADDRESS2 would all point to the same value. The runtime symbol table used a linear search so that a program which used many distinct variables would run much slower than a program which used a single array for all its variables.
It was delivered on paper tape and in its original version took 4 KB of memory. The extended 8 KB version was then generalized into BASIC-80 (8080/85, Z80), and ported into BASIC-68 (6800), BASIC-69 (6809), and MOS Technology 6502-BASIC (unfortunately spilling over to 9 KB, in an era when 8 KB ROM chips were standard), as well as the 16-bit BASIC-86 (8086/88). It was ideal for ROM-based computers since it did not require an editor (each line requires a number), nor a disk drive to store object code or linked executable. It was less sophisticated than software for industrial desktop computers, which had dedicated keys to load, store, and keys for editing within a line and debugging, but personal computer pricing, in contrast, started at $1,565, not $7,000.
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 personal computers of the 1970s and especially the 1980s, and extended along the way. Contrary to the original Altair BASIC, most home computer BASICs were resident in ROM, and thus were available on the machines at power-on in the form of the characteristic "READY." prompt. Hence, Microsoft's and other variants of BASIC constituted a significant and visible part of the user interface of many home computers' rudimentary operating systems.
No variety of Microsoft BASIC (BASICA, GW-BASIC, QuickBasic, QBasic) is currently distributed with Microsoft Windows or DOS. However, versions which will still run on modern machines can be downloaded from various internet sites or be found on old DOS disks. The latest incarnation of Microsoft BASIC is Visual Basic .NET which incorporates some features from C++ and C# and can be used to develop web forms, Windows forms, console applications and server-based applications. Most .NET code samples are presented in VB.NET as well as C#, and VB.NET continues to be favored by former Visual Basic programmers.
In October 2008, Microsoft released Small Basic. The language itself has only 14 keywords. Small Basic Version 1.0 (12 June 2011) was released with an updated Microsoft MSDN website that included a full teacher curriculum, a Getting Started Guide, and several e-books. Small Basic exists to help students as young as age eight learn the foundations of computer programming and then graduate to Visual Basic via the downloadable software, Visual Studio Express, where they can continue to build on the foundation by learning Visual C#, VB.NET, and Visual C++.
^ abcdSources differ in regard to the first NCR data entry terminal integrating support for the FAT file system. According to Stephen Manes and Paul Andrews, "Gates", development was for a NCR 8200 in late 1977, incorrectly classified as a floppy-based upgrade to the NCR 7200, which had been released in 1975-11 and was built around an Intel 8080 8-bit processor, but was cassette-based only. However, the NCR Century 8200 was a 16-bit minicomputer, onto which several data entry terminals could be hooked up. Marc McDonald even remembered a NCR 8500, a mainframe of the Criterion series, which can be ruled out as well. Other sources indicate that either the NCR 7200 itself or its successor were the actual target platform. The NCR 7500 series was released in 1978, based on a similar 8080 hardware, but now including NCR 7520 and 7530 models featuring 8-inch diskettes. NCR Basic +6, a precursor or adaptation of Microsoft Standalone Disk BASIC-80 was available for them at least since 1979. One source claims that a special NCR 7200 model variant with two 8-inch diskettes and Microsoft BASIC existed and was imported by NCR Sydney into Australia the least.