BASIC

While time-sharing was a significant and often overlooked revolution in computing, allowing programmers interactive access to the machine and eliminating the highly regulated ritual of submission of punched card stacks, it was only the first revolution in which BASIC played a critical role. The next revolution would change industry and reshape everyday interactions with computing. It was the beginning of the home computer or minicomputer era, and the face that launched a thousand ships was a panel of switches and LEDs on the cover of the January 1975 ''Popular Electronics.'' The image was of the Altair 8800. This $395 machine ($495 assembled) was described consistently there and throughout the magazine as a "minicomputer," rather than a "microcomputer." Nevertheless, the article about this device describes the many virtues of a useful computer for individuals and the headline of the editorial on page 4 clearly proclaims "THE HOME COMPUTER IS HERE!"

The article describing the Altair 8800 claims that the computer can be used as a "Sophisticated intrusion alarm system," an "Automatic IC tester," an "Autopilot for planes, boats, etc.," a "Time-share computer system," a "Brain for a robot," and a "Printed matter-to-Braille converter for the blind," among other things, noting that "many of these applications can be performed simultaneously." (p. 38) As it happened, even the applications that were within the capabilities of the device were rather difficult to realize since the system, as delivered or assembled, could only be programmed in machine language, and unless one happened to have a Teletype or other terminal lying around, the programming had to be done using the toggle switches on the front panel. From the outset, it was clear to many that the Altair 8800 could really use was a programming language that facilitated experimentation. The ''Popular Mechanics'' article actually mentions four programming languages by way of explaining the hardware/software distinction (p. 34); one of these is BASIC, which was the language of most interest to early Altair 8800 users.

The two major successful efforts to develop a BASIC interpreter for the Altair are important and intriguing. While this tale of two BASICs doesn't clearly show the best of BASIC and the worst of BASIC, they do show two extremes in software development: one commercial, closely coordinated with hardware manufacturers, and highly tied to licensing and cost structures; the other community-based, non-profit, and "copyleft." The BASICs that led in these directions were Microsoft's Altair BASIC, the official BASIC for the platform, licensed to the manufacturer of the system, MITS; and Tiny BASIC, which originated at the People's Computer Company or PCC. The Commodore 64's BASIC is directly descended from Microsoft's Altair BASIC -- it is, although this is not visible on the screen, a Microsoft product. At the same time, the 10 PRINT program participated in a context of BASIC sharing and exploration that was strongly influenced by, if not developed at, the People's Computer Company.

By 1975, Gates was at Harvard University and he and Allen were ready to envision a project with broader reach. They devised the idea of writing BASIC for the Altair and contacted Ed Roberts' company MITS to ask if they would be interested in a BASIC for their system. As with their Traf-O-Data system, they programmed on a university's computer system using a simulator. What they were programming at this point was, of course, a modified and minimized version of the original 1964 BASIC. Given how often the success of personal computing software is attributed to entreprenurial and business advances, it's remarkable that Microsoft's first product was developed using Harvard's computer and by implementing Dartmouth's programming language.

Gates and Allen were successful in fitting their BASIC interpreter into an austere 4KB and leaving some room for a BASIC program. They turned to a time-sharing Allen flew to visit MITS in Albuquerque, taking the program on paper tape. The demo was a success and was licensed by MITS; Gates and Allen moved to New Mexico to create new versions of BASIC for the Altair and to maintain the original code.

Microsoft's Windows is one example of a two-sided platform. On one side, computers seemed to need an operating system and desktop environment to function. This leads hardware manufacturers such as Dell to purchase licenses to Windows and to include the software with their systems. On the other side, computers are only valuable if there are applications written for them. Microsoft writes some of the applications for Windows, but third-party developers write many. The abundance of software has a network effect that is positive for Microsoft: it encourages users to stay with Windows.

Of course, Windows was not the first two-sided platform, nor even Microsoft's first. By retaining the rights to what IBM called PC-DOS, Microsoft had previously been able to license MS-DOS to other companies, much as they would later sell OEM copies of Windows to them. And before that, there are continuities with the company's first product line, Microsoft BASIC. BASIC was a programming language, not an operating system, but the presence of BASIC allowed for programs to be written on a computer and sometimes sold. There were two sides to BASIC: The computer companies, beginning with MITS, who wanted it on their machines and the computer hobbyists who wanted to write BASIC programs. At Gates and Allen's company, the success of BASIC and the essential business plan used with that family of software products helped to develop the later success of MS-DOS and Windows.