Fairchild 9440

The name "MICROFLAME" was part of a wider branding exercise called "FIRE", which was a development software system.

In order to lower design complexity, and thus board size and cost, the arithmetic logic unit (ALU) was only 4-bits wide, implemented using a single 74181 IC.

This meant it required four machine cycles to complete a 16-bit instruction, but it also allowed the system to be much less expensive than competing minicomputers from Digital Equipment Corporation (DEC) or Hewlett-Packard.

[1] In 1970, DG introduced the SuperNOVA, which featured a full 16-bit wide ALU using four 74181's in bit-slice fashion, and thus ran about four times as fast as the original NOVA.

This also meant there were two different central processing unit designs implementing the same underlying instruction set architecture (ISA).

As the development of both designs continued, the two were modified so the faster version could be dropped into existing machines originally running the lower-speed hardware.

Improving semiconductor fabrication processes, especially through the 1970s, put increasing pressure on the individual-IC CPU designs like the NOVA.

Several similar designs appeared during this period, including the Texas Instruments TMS 9900, which implemented their TI-990 minicomputer, and the Intersil 6100, a single-chip version of the PDP-8.

DG needed to respond to these systems, and began development of the microNOVA mN601, a single-chip design that implemented the NOVA 3 instruction set.

[1] It also added hardware single-precision multiply and divide, formerly an optional add-on for NOVA systems.

[1] The mN601 was implemented using NMOS technology, and thus required four separate input voltages from the power supply.

It ran at fairly low speeds, normally using a 240 ns clock (~4.2 MHz), completing instructions in 2.4 to 10 μs.

[2] For reasons that are not found in the historical record, Fairchild decided to produce their own single-chip implementation of the NOVA design, without Data General's approval.

The combination of the higher prices and lawsuit made the 9440 a slow seller, and it was not picked up for second-source by any of Fairchild's normal partners.

[4] Schlumberger decided to exit the business, and in 1987 they sold Fairchild to National Semiconductor, who immediately ended production of the line.

[4] Strobe Data, who made 9445-based add-in boards for PCs, contracted IC Designs to continue production of what became the ICD9445.

[3] In contrast, the NOVA performed an optional interrupt that allowed the processor itself to move data, jumping through an address in memory location 0001.

This reached the market in 1985, offering a built-in math processor, an optional external chip on most other 1750A implementations.