Editing BASIC-PLUS (section)

==History==
In the mid-1960s, DEC won a sale for a [[PDP-6]] [[mainframe computer]] to the [[RAND Corporation]] who were looking for a faster machine to run their interactive [[JOSS]] programming language. The next year, DEC introduced the much smaller [[PDP-8]], generally considered the first successful [[minicomputer]]. For this machine they developed a cut-down version of JOSS known as [[FOCAL programming language|FOCAL]], which became popular on the PDP-8, one of the best-selling computers of the era.{{sfn|Ahl|2013}}

The same year that RAND introduced JOSS, [[Dartmouth University]] introduced the first version of [[Dartmouth BASIC]]. This was soon ported to several other platforms, and by the late 1960s it was making major inroads to the computer industry as an interactive language intended to be used with [[timesharing]] systems. By the late 1960s, most vendors were introducing a BASIC for their platform, including [[IBM]] and the major online timesharing companies like [[Tymshare]]'s [[SUPER BASIC]].

DEC continued to push FOCAL to their customers, as much for [[not invented here]] reasons as any technical advantage. By the late 1968s, DEC's educational department was finding it increasingly difficult to pitch FOCAL to prospective customers as BASIC began to take over. Management was uninterested, so in 1969 [[David H. Ahl]] took it upon himself to hire a programmer to write [[BASIC-8]] for the PDP-8. It was an immediate success and became one of DEC's biggest software sellers.{{sfn|Ahl|2013}}

The same year, DEC began the design effort for a new computer that emerged as the [[PDP-11]].{{sfn|Fleig|1983|p=52}} The first [[operating system]] for the platform was [[BATCH-11/DOS-11|DOS-11]], a single user system later retargeted for [[batch processing]]. Timesharing was a major goal for the new machine, so a second system, MUM-1 for Multi-User Monitor, was developed based on DOS, along with a [[BASIC-11]] that ran on top. The result was very slow.{{sfn|Dick|1990}}

The company eventually concluded it needed an entirely new timesharing OS, and put Tom Barnett and Nathan Teicholtz in charge of developing it. They formed a new team to develop what was then known as IOX, Input Output eXecutive, on 11 June 1970. Teicholtz, the technical lead, was formerly part of the [[TSS-8]] effort on the PDP-8. Among the many new concepts IOX was to include was the idea of using a programming language that could act as a [[command shell]] programming system as well. An argument broke out in the company about what language it should be based on. Some suggested it be FOCAL, largely because DEC felt they should do their own thing. Others felt that not supporting BASIC would be a major problem for the machine's popularity. As there seemed to be no overwhelming argument either way on technical grounds, the decision was left to the marketing department, who chose BASIC.{{sfn|Dick|1990}} In the end, they decided to do both, and have a BASIC dialect that would add some features from FOCAL as well.{{sfn|Fleig|1983|p=52}}

As the OS side of the project grew, the engineering load took over all of the available programming time and there was no one working on the BASIC.{{sfn|Dick|1990}} At a chance meeting while buying an airplane, Tim Hart found the seller worked at DEC and they ended up talking about the problems DEC was having. Through this opening, Hart, along with two long-time friends Tom Evans and Tom Griffiths who had formed EGH Inc., received a tender from DEC on 25 August. Because they thought it would be a fun project, they put in a very low bid at $10,500 on 4 September. To their surprise they won the contract on 18 September, but DEC realized the price was too low and offered to make it up through a $3000 bonus clause.{{sfn|Fleig|1983|p=53}}

Previously, DEC had introduced several different BASIC dialects for their different platforms, and these were both different enough to require conversion when moving between machines, as well as generally underwhelming compared to other platforms.{{sfn|Fleig|1983|p=53}} BASIC-PLUS introduced many new features that made it among the more complete dialects, including matrix math, file handing, and other features previously only see on the mainframe system. BASIC-PLUS would go on to be the basis for all future dialects from the company.

The original concept was that EGH would write only the compiler{{efn|In modern terms this would be considered a tokenizer, not a compiler in the current use of the term.}} and related utilities, while DEC would write the [[runtime system]] which would be separate. The idea was that systems with limited amounts of memory and [[secondary storage]] would be supplied only with the runtime and small size of the runtime and the [[intermediate language]] (IL) code from the compiler would allow it to run. Development would require a machine with more resources, but simply running the resulting programs would work even on the smallest machines. EGH was initially supposed to write only the compiler, but over time they were put in charge of the entire system, which they delivered in January 1971. The idea of a runtime-only system was later dropped.{{sfn|Dick|1990}}

IOX was eventually renamed RTST-11, and shipped with BASIC-PLUS in 1971.{{sfn|Fleig|1983|p=53}}