BASIC

The next step in programming was machine language. A program in machine language is simply a sequence of numbers. On the ENIAC, these were decimal (base 10) numbers, but different bases were used on other significant early systems. The EDVAC used binary; the ORDVAC, octal; and the BRLESC, sexadecimal (Bergin p. 62). In all of these cases, programmers needed to arduously determine the sequence of numbers that would constitute a program, writing something that did not look remotely like human language. Each operation the computer was to perform corresponded to a number, while the operands, if there were any, were provided as similar numbers. For instance, to jump unconditionally to a particular absolute address, an opcode such as "76" (in base 10) is used, followed by two bytes specifying the address. In fact, this is the opcode used for an unconditional branch to an absolute address on the Commodore 64.

A more legible form of code arose in the second generation programming languages, assembly languages. Assembly allows the use of mnemonics for operators such as LDA ("load accumulator"), JMP ("jump"), and INC ("increment memory") to stand in for the less easily remembered numeric codes. On the Commodore 64, the letters JMP followed by an absolute address are converted by the assembler to "76" in a machine language program. The first assembler ran on Cambridge University's EDSAC, the first stored-program computer, in 1949 (Campbell-Kelly and Aspray p. 184).

FORTRAN's GOTO command was the basis for the GOTO in the original BASIC (MoP p. 86), which of course was carried over into Commodore 64 BASIC. GOTO functions in the same way the assembly language JMP does. There is not much of an advantage to using BASIC if one is simply interested in easily writing JMP, but other BASIC commands, such as PRINT, allow one to efficiently accomplish what would take very many machine-language operations.

In 1962, change was sweeping through the remote Dartmouth campus. ''Time'' noted late that year, in article that declared the college was coming "out of the woods," that the school had built a major new arts center and that John Kemeny, who had made full professor at age 27, had built "the best college math department in the country." That year, Kemeny and his colleague Thomas Kurtz had started developing a time-sharing system and a new programming language for the education of all students at Dartmouth -- not just those studying math, science, or engineering. They aimed to make a radical improvement in access to computers and to computer programming. "While the availability of FORTRAN extended computer usage from a handful of experts to thousands of scientific users," Kemeny wrote, "we at Dartmouth envisaged the possibility of millions of people writing their own computer programs." (Man and the Computer p. 30)

To reach millions, Kemeny and Kurtz would clearly have to significantly lower the existing barriers to programming, barriers which were related not only to the esoterics of programming languages but also to the material nature of programming. The two began working with a team of undergraduates to develop the Dartmouth Timesharing System, and with it the BASIC programming language. They considered developing a subset of FORTRAN or Algol, but found these options unsuitable (Masterminds of Programming p. 79). As Kurtz told an interviewer, "we wanted ... to get away from the requirements that punched cards imposed on users, which was that things had to be on certain columns on the card." (Masterminds of Programming p. 81) They saw the value of an interactive time-sharing system for allowing users to quickly correct minor errors rather than coming back 24 hours later with a new stack of punched cards for their next scheduled batch job. They also relaxed some of the specific requirements that were tied to using keypunch machines and cards. Oddly enough, BASIC was so relaxed that spaces between tokens were optional in Dartmouth's versions of the language. Spaces were ignored, as Kurtz explains, because "some people, especially faculty members, couldn't type very well." (MoP p. 81) This aspect of Dartmouth BASIC was carried over onto the Commodore 64, as mentioned in the introduction.

DTSS and the versions of BASIC that ran on it served almost all of the students at that college: Kemeny stated in 1971 that 90% of seven classes of freshmen had received computer training. Access to Dartmouth's system extended to many other campuses, and it was not the only time-sharing system with BASIC. By 1965, General Electric -- on whose computers DTSS and the original BASIC ran -- was offering a commercial time-sharing service that included BASIC (Waldrop p. 292). Before the microcomputer revolution, other college and university students were taking required courses in computing using BASIC -- at NYU's business school, for instance. Even before the arrival of home computers with built-in BASIC, the language had extensive influence. And even before the microcomputer era and the full toppling of BASIC's Tower of Babel, the permissive attitude of Kemeny and Kurtz had led to many different implementations of BASIC for different systems. Writing in 1975, one author commented: "BASIC systems differ among themselves in much the same way that the English language as we know it differs among the English-speaking nations around the globe." (Mullish p. 6) BASIC's openness and widespread adoption, combined with a lack of any enforced standard, meant that the language wasn't as independent of particular hardware as had been hoped.

While BASIC was a significant project at Dartmouth, it was only one part of the push to expand access to computing that resulted in DTSS, allowed sites all around the East Coast to connect to Dartmouth's computers, and fostered a more productive and creative relationship to computing. In his 1972 book ''Man and the Computer,'' Kemeny defends programming and playing games and other "recreational" uses of the computer as important, writing that such activities are relaxing and help people to overcome their fear of computers (p. 35). Kemeny also describes some of the context in which BASIC programming was done at Dartmouth: "The computation center is run in a manner analogous to Dartmouth's million-volume open-stack library. Just as any student may go in and browse the library or check out any book he wishes without asking for permission or explaining why he wants that particular book, he may use the computation center without asking permission or explaining why he is running a particular program." (Man and the Computer p. 33) It was not only the BASIC programming language, but also the development of this permissive attitude toward computing that allowed for programs with no obvious military, business, or scientific purpose -- programs such as 10 PRINT -- to come about.

In designing BASIC, Kemeny and Kurtz needed to distinguish variables that hold numeric values from those that hold strings of text. They chose to have string variables and string functions end with "$," so that a string variable might be named A$ and the function that produced one-character strings based on ASCII values was called CHR$. They selected the dollar sign because "There were not so many keys on a Teletype, and we needed to find one that had not yet been used for BASIC. Of the few remaining ones, none seemed very appropriate. Then one of us observed that $ looks like S for string." (BtB p. 28)

The story of Microsoft BASIC, and of Microsoft, begins with Paul Allen catching sight of the now-famous ''Popular Electronics'' in December 1974, just after the issue hit the stands. Allen read the Altair 8800 article and raced to show it to his friend and business partner Bill Gates, telling him, "Well here's our opportunity to do something with BASIC." (Wallace & Erikson p. 67) The two had already earned some limited success when Gates was still in high school. Their first venture was called Traf-O-Data and produced hardware and software to count cars. They programmed the Intel 8008 using a simulator running on a Washington State University mainframe.

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 phoned up Ed Roberts at MITS to ask if he would be interested in having their BASIC for his system. Roberts said he would buy the first version that worked (Wallace & Erikson p. 74). As Gates and Allen had done when developing their Traf-O-Data system, they initially 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 entrepreneurial and business advances and to Microsoft in particular, it's remarkable that Microsoft's first product was developed borrowing time from Harvard's computer and was (as Microsoft clearly acknowledged) an implementation of Dartmouth's programming language.

Gates and Allen devised the Altair BASIC project and did most of the programming, but there was a third Altair BASIC programmer, a sort of legendary fifth Beatle of Microsoft (or at least of Altair BASIC). This was Monte Davidoff, who wrote the floating-point routines. Gates and Allen were discussing how they needed to code these up when Davidoff, a student who was sitting with them at the table, spoke up and said he could write them. After talking it over with him, they enlisted him to contribute these (Wallace & Erikson p. 76-77).

The code of this first Microsoft project is mainly by Gates and Allen, though, with Gates listed as first author. Comments at the beginning of the code declare, "BILL GATES WROTE THE RUNTIME STUFF," which he did over a period of eight weeks at Harvard. Gates would say years later that this 4 KB BASIC interpreter "was the coolest program I ever wrote" (Wallace & Erikson p. 76-77).