Whatever Happened to The iAPX432 — Intel’s Dream Chip
by John C. Dvorak
Anyone who was around in the early 1980’s recalls the Intel 432 chip — a processor that was one of the biggest flops in Intel’s history, but one of the more fascinating chips the company designed. The company intended this chip and its subsequent prodigies to be the desktop computer chips of the 1980’s and 1990’s. It appeared at the time that the X86 architecture was to end with the 80286 insofar as desktop computing was concerned. Even the numbering schemes for the chips changed as Intel devised the iAPX moniker for its entire line of processors. iAPX stood for Intel’s Advanced Performance Architecture. Yes, the “X” is there in the pronunciation of “architecture” someplace. The iAPX 432 was to be the flagship. All other chips were renamed — the iAPX 286, for instance. Everything changed back once the 432 hit the market and was determined to be a dog. The 432 was simply too ambitious an undertaking. More interesting is the fact that the 432 was optimized to run Ada programs. Ada had then recently been named by a government committee as the knighted programming language to replace all others. Of course nobody paid any attention to this edict. Nobody, that is, except Intel.
It’s hard to say when the Ada aspect of the chip came into play since the design work began in 1975 years before the Ada fad. The idea was to deign a chip that was object-oriented where typical linear access methods were not done. All sorts of advanced features were included — all adding to overhead and complexity. The first announcement of the 432 part was in 1980 with first shipments in 1981. The dates for the chips are pretty cloudy since the processor was actually sold in four parts which were released at various stages. The Processor itself was made of two chips (decoder/sequencer and execution unit) and a third chip of the original three chip set was an I/O controller. Later a bus interface unit and memory control unit were added to the mix. There were a lot of pieces involved in this chip but today’s Pentium Pro consists of two chips and other needed support chips too. Curiously the lead engineer for the 432 was superstar designer Fred Pollack who became the lead architect for the Pentium Pro. While there is supposed to be no similarities in the designs of the 432 and any X86 chips, this multiple chip aspect looks to be a carry over.
Fred was not the only superstar involved with the 432 chip as names like John Doerr (Famous venture Capitalist with Kleiner, Perkins), Dave Best (another venture capitalist), Casey Powell (Chairman at Sequent) and others were involved.
Once released the chip proved to be a woofing dog the designers gave up on it as a product and moved forward with some of the ideas used to design the chip. It’s believed that it was given up on after 1984 although supplies of the chipset may have still been available as late as 1993. The ideas behind the chip continued and slowly evolved into what is today’s Intel 960 embedded processor. The 960 began as a joint venture between Siemens and Intel using 432 ideas to create a general purpose machine. Again Fred Pollack was the lead architect. It was quickly determined that the early 960 designs made it perfect as an embedded controller. During the various iterations of the chip design Intel actually had invented a 33-bit processor that was never manufactured, a curiosity I found amusing. Another amusing aspect to this is that floating around someplace is a 960 Ada compiler — the same Ada optimization still exists within this chip but Intel doesn’t like to mention it. One anonymous Intel engineer told me, “There’s not much of a market for embedded processors that run Ada!”
Unlike the 432, the 960 has become one of Intel’s hottest selling chips and few realize it’s heritage since it’s most often associated with the 860 RISC chip with which it has no architectural connection according to Intel. I’m sure if it was named the 432/II it would not have been as successful. Intel notes that the 860 was designed in California and the 960 designed again in Portland where the 432 was done.
The 432 has since been discussed in many computing circles and is considered the most CISC of the CISC chips ever invented with the possible exception of a little known processor called the Rekursiv, which was actually a processor board created to replace a VAX in a factory automation application. The issue of CISC and RISC rubs a nerve at Intel and discussion ends rapidly as the company tells everyone that RISC was a marketing gimmick and the term is almost meaningless. Intel’s argumentative Will Swope asked me the standard Intel query, “If the PowerPC has more instructions than an X86 chip, then how can it be a reduced instruction set chip?” According to the company the only difference between RISC and CISC after boiling it down is that RISC has a fixed length instruction set which utilized a simpler decoder mechanism. Nothing else matters.
Intel itself has kind of avoided discussing the 432 as it reflects badly on a string of recent success. If you go to the Intel web site and look at its own history of great processors, the 432 isn’t even mentioned. This is curious since at the time of its introduction it was considered the greatest chip the company ever designed and was to lead us to the 21st Century. If you search on the Intel site for data on the 432 you’ll find nothing except a mention of the chip on an off site Intel web page in Germany (written in German). Of course old-timers like to chide Intel about the 432 to prove a point of vulnerability and I suppose Intel would like the story to go away. I suppose this particular column won’t help them much, will it?
