Talk:F14 CADC

Multichip or not multichip?

The F14 CADC was NOT multichip. This is a cannard put out by the pro-Intel forces to attempt to discredit the CADC as being a microprocessor developed before the 4004. The only thing the CADC did NOT have that the Intel 4004 does is a program counter. The program counter in the CADC architecture was placed on the RAS (Random Access Storage, otherwise known as RAM) and ROM chips to facilitate multi-tasking/processing. A PC could have easily been implemented on the primary processor but this was a pratical design decision only.

Read more about the CADC at the CADC website. --Anonymous

This is all extremely interesting. The reason I myself haven't looked more closely into whether the CADC was a single- or multi-chip µP is quite simply the website's overall emphasis on the word "chip set", implying more than one chip to make out the CPU. (However, now that I think about it, the 4004 was also an integral part of a chipset---the MCS-4---i.e. RAMs, ROMs, I/O circuits, etc, without which the CPU would be pretty useless.)

After reading your comment above and browsing Holt's 1971 paper I'm still not 100% sure I completely understand how the CADC system would make up a CPU by combining a single unit of the chipset with a ROM (and optionally a RAS). Therefore, could you please specify what you mean by the "primary processor"? Is it one of the PMU/PDU/SLF units, or one of the other units mentioned?

As for the "first µP" question, IMO two points of consideration are:

1. The CADC is clearly a much more capable and in fact scalable µP system---more of "a real computer"---than the 4004 & Co
2. The 4004 may arguably still be reckoned as the first single chip µP if it is the only CPU fitting the "official definition"(?) of a single chip µP

But another way to look at all this would perhaps be to consider how many chips one actually needs to build a simple computer: the 4004 would also at least need a ROM chip, as the CADC does, to hold its instructions. A RAS/RAM is not essential, of course, since the computer in question might just be doing some simple I/O and calculations fitting within its on-chip registers. Please comment, folks. --Wernher 04:42, 23 November 2005 (UTC)

"In the CADC there is one chip (SLF-CPU) that acts as the CPU and performs the arithmetic functions. The chip set is a parallel system where many CPU's and RAS (RAM) can be connected together. In my opinion, there is NO comparison to the 4004. Both designs were made from the exact same technology, however, one was 20-bit and one 4-bit, one was commercial for the desktop and the other was for rugged and high demand military. Like I said, no comparison. Ray Holt, CADC designer. May 12, 2012"

Four-Phase Systems AL1

There is also the Four Phase Systems AL8, which preceded the CADC by a couple years, and may well have also been a single-chip 8-bit microprocessor, but it was intended to be utilized as an 8-bit slice of a 24-bit architecture. --Anonymous

Perhaps you mean the AL1? It almost seems to be a "chip lost to history". :-) Google got me one barely "usable" hit on it, The 8008 and the AL1, which is nothing more than a mailing list excerpt from the "Interesting People Elist". I have written to one of the participants, Nick Tredennick, asking him if he could help us get some more docs on the AL1. --Wernher 06:03, 23 November 2005 (UTC)