Fairchild 9440

Lore & Background

The 9440 was developed by Fairchild Semiconductor without Data General's approval, implementing the Nova 2 instruction set. The courts had previously decided that instruction sets were not subject to copyright, and several companies had produced IBM-compatible systems using different internal implementations. Data General had not acted against earlier Nova-like designs such as the IMP-16 and PACE. However, Data General sued Fairchild in 1977, not for design infringement, but claiming that Fairchild was enticing DG's customers to break their licensing agreements, which stipulated that DG software could only run on DG hardware. Fairchild counter-sued the next year, claiming DG's licensing broke anti-competition laws.

Internally, the 9440 was structurally different from the Nova 2 CPUs; as the data sheet stated, 'Though structurally different from the CPUs of the Data General NOVA line of minicomputers, the 9440 offers comparable performance and executes the same instruction set.' This was possible because the instruction set was implemented in microcode. The 9440 ran at up to 12 MHz, about the speed of a Nova 1200, and integrated the clock generator and oscillator, though it could accept an external clock. It lacked the hardware stack introduced on the Nova 3 and also lacked hardware multiply and divide.

The 9440 was much more expensive than Data General's own microNOVA mN601, selling for $395 in lots of 100 including software, compared to $95 for the mN601. The combination of higher price and ongoing litigation made the 9440 a slow seller, and it was not second-sourced by any of Fairchild's normal partners.

Reader's Guide

The Fairchild 9440 represents an early attempt to implement a minicomputer instruction set on a single chip, predating the widespread adoption of 16-bit microprocessors. Its use of bipolar I3L technology allowed it to run at speeds comparable to the original Nova minicomputer while requiring only a single +5V power supply, a significant simplification over the NMOS mN601 which needed four separate voltages. The 9440's integration of the clock generator further reduced system complexity.

The 9440's significance is tempered by its commercial failure, driven by high pricing and legal battles with Data General. The lawsuits, which eventually grew to eleven cases, dragged on for years and were only settled in September 1986 when Data General paid Fairchild over $52 million. By that time, the minicomputer market was collapsing and interest in the 9440 was long dead. The 9440's legacy is as a technically interesting but commercially unsuccessful implementation of the Nova architecture, and as a precursor to the faster but delayed 9445. The underlying core of the 9445 was later used to implement the 9450, which used new microcode to implement the MIL-STD-1750A instruction set.

Did You Know?

• The 9440 was fabricated using Fairchild's proprietary 3-micron bipolar Isoplanar Integrated Injection Logic (I3L) process.
• The 9440 required only a single +5V power supply, unlike the four-level supply of the NMOS mN601.
• Data General sued Fairchild in 1977, not for design infringement, but for enticing customers to break licensing agreements.