For the 8/I, the decision was made to stay with small boards, using the new "flip-chip" packaging for a modest improvement in density. During the period when the PDP-8 was being developed, the introduction of ASCII and its major update in 1967 led to a new generation of designs with word lengths that were multiples of 8 bits rather than multiples of 6 bits as in most previous designs.
de Castro was convinced that it was possible to improve upon the PDP-8 by building a 16-bit minicomputer CPU on a single 15-inch square board. In 1967, de Castro began a new design effort known as "PDP-X" which included several advanced features.
He was not alone; in late 1967 a group of like-minded engineers formed to consider such a machine.
As the complexity of a flip-flop was being rapidly reduced as they were implemented in chips, the design offset the lack of addressing modes of the load/store design by adding four general-purpose accumulators, instead of the single register that would be found in similar low-cost offerings like the PDP series. ===Nova introduction=== Late in 1967, Richman introduced the group to New York-based lawyer Fred Adler, who began canvassing various funding sources for seed capital.
It was eventually canceled in the spring of 1968. ===Design of the Nova=== Cancelation of the PDP-X prompted de Castro to consider leaving DEC to build a system on his own.
By 1968, Adler had arranged a major funding deal with a consortium of venture capital funds from the Boston area, who agreed to provide an initial $400,000 investment with a second $400,000 available for production ramp-up.
de Castro, Burkhart and Sogge quit DEC and started Data General (DG) on 15 April 1968.
Initially the new memory was also very expensive and ran hot, so it was not widely used. ===1200 and 800=== As a demonstration of the power of their Micromatrix gate array technology, in 1968 Fairchild prototyped the 4711, a single-chip 4-bit ALU.
The Nova family was very popular in the 1970s and ultimately sold tens of thousands of units. The first model, known simply as "Nova", was released in 1969.
DG officially released the Nova in 1969 at a base price of US$3,995 (), advertising it as "the best small computer in the world." The basic model was not very useful out of the box, and adding 4 kW (8 kB) RAM in the form of core memory typically brought the price up to $7,995.
The introduction of the Signetics 8260 in 1969 forced their hand; both Texas Instruments and Fairchild introduced 4-bit ALUs of their own in 1970, the 74181 and 9341, respectively.
The Nova family was very popular in the 1970s and ultimately sold tens of thousands of units. The first model, known simply as "Nova", was released in 1969.
This emerged in 1970 as the PDP-11, a much more complex design that was as different from the PDP-X as the Nova was.
In the spring of 1970 they hired a new designer, Larry Seligman, to leapfrog any possible machine in the making.
Performance could be further improved by replacing the core with read-only memory; lacking core's read/write cycle, this could be accessed at 300 ns for a dramatic performance boost. The resulting machine, known as the SuperNOVA, was released in 1970.
The introduction of the Signetics 8260 in 1969 forced their hand; both Texas Instruments and Fairchild introduced 4-bit ALUs of their own in 1970, the 74181 and 9341, respectively.
Gruner was put in charge of the low-cost machine while Seligman designed a matching high-performance version. Gruner's low-cost model launched in 1970 as the Nova 1200, the 1200 referring to the use of the original Nova's 1,200 ns core memory.
Seligman's repackaged four-ALU SuperNOVA was released in 1971 as the Nova 800, resulting in the somewhat confusing naming where the lower-numbered model has higher performance.
This design became very complex and was ultimately canceled years later. While these efforts were underway, work on the Nova line continued. ====840==== The 840, first offered in 1973, also included a new paged memory system allowing for addresses of up to 17-bits.
Actually installing this much memory required considerable space; the 840 shipped in a large 14-slot case. ====Nova 2==== The next version was the Nova 2, with the first versions shipping in 1973.
Sales accelerated as newer versions were introduced, and by 1975 the company had annual sales of $100 million. ===SuperNOVA=== Ken Olsen had publicly predicted that DG would fail, but with the release of the Nova it was clear that was not going to happen.
Versions were available with four ("2/4"), seven and ten ("2/10") slots. ====Nova 3==== The Nova 3 of 1975 added two more registers, used to control access to a built-in stack.
A single-chip implementation was also introduced as the microNOVA in 1977, but did not see widespread use as the market moved to new microprocessor designs.
Fairchild Semiconductor also introduced a microprocessor version of the Nova in 1977, the Fairchild 9440, but it also saw limited use in the market. The Nova line was succeeded by the Data General Eclipse, which was similar in most ways but added virtual memory support and other features required by modern operating systems.
The original microNOVA with the “mN601” processor shipped in 1977.
It was followed by the microNOVA MP/100 in 1979, which reduced the CPU to a single VLSI chip, the mN602.
A 32-bit upgrade of the Eclipse resulted in the Eclipse MV series of the 1980s. ==History== ===Edson de Castro and the PDP-X=== Edson de Castro was the Product Manager of the pioneering Digital Equipment Corporation (DEC) PDP-8, a 12-bit computer widely referred to as the first true minicomputer.
The larger-board construction also made the Nova more reliable, which made it especially attractive for industrial or lab settings. The new design used a simple load–store architecture which would reemerge in the RISC designs in the 1980s.
Enterprise shipped in 1981, running RDOS, but the introduction of the IBM PC the same year made most other machines disappear under the radar. ===Nova’s legacy=== The Nova influenced the design of both the Xerox Alto (1973) and Apple I (1976) computers, and its architecture was the basis for the Computervision CGP (Computervision Graphics Processor) series.
The development of the MV-series was documented in Tracy Kidder's popular 1981 book, The Soul of a New Machine.
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