Convex Computer was a computer company that produced a number of "minisupercomputers", supercomputers for small to medium-sized businesses. Their later Exemplar series of parallel computing machines was based on the Hewlett-Packard PA-RISC CPU series, and in 1995 HP bought the company. Exemplar machines were offered for sale by HP for some time.
Convex was formed in 1982 by Bob Paluck and Steve Wallach in Richardson, Texas. Their product concept was not particularly original: they planned on producing a machine very similar in architecture to the Cray Research vector processor machines, but with a somewhat lower performance, and at a much lower price point. In order to lower costs, the Convex designs were not as technologically aggressive as Cray's, and were based on more mainstream chip technology, attempting to make up for the loss in performance in other ways.
Their first machine was the C1, released in 1985. The C1 was very similar to the Cray-1 in general design, but used a slower memory and main CPU. They offset this by increasing the capabilities of the vector units, including 128 64-bit registers, double that of the Cray. It also used virtual memory as opposed to the real memory system of the Cray machines. It was based on CMOS chips, and generally rated at 20 MFLOPS peak for double precision (64 bits), and 40 MFLOPS peak for single precision (32 bits). They also invested heavily in advanced automatic vectorizing compilers in order to gain performance when existing programs were ported to their systems. The machines ran a version of Unix known as ConvexOS.
The C2 was a crossbar-interconnected multiprocessor version of the C1, with up to 4 CPUs, released in 1988. It used newer ECL chips for a boost in clock speed from 10 MHz to 25 MHz, and rated at 50 MFLOPS peak for double precision per CPU (100 MFLOPS peak for single precision). This was followed by the C3 in 1991, essentially similar to the C2 but with a faster clock and support for up to 8 CPUs. Various configurations of the C3 were offered, with between 50 to 240 MFLOPS per CPU. Another speed boost was planned for the C4, which moved the hardware implementation to GaAs-based chips (following an evolution identical to that of the Cray machines), but the effort was scrapped.
Instead Convex introduced an entirely new design as the Exemplar. Unlike the C-series machine, the Exemplar was a parallel-computing machine based on off-the-shelf HP-PA RISC chips, connected together using SCI. First introduced in 1994, the Exemplar technology was generic enough that HP decided to buy Convex in order to sell the Exemplar machines directly.
