4 ms·

Not dirrctly in the article, but a key change within Intel after the 4004 was removing the mandate that all chips be a 16 pin DIP. This severely limited perform

Not dirrctly in the article, but a key change within Intel after the 4004 was removing the mandate that all chips be a 16 pin DIP. This severely limited performance of the 4004 by not having enough lines to do data etc in one clock, instead having to shift register and serialize it.

guerrilla 5y ago
I think it would have been impossible otherwise. It's still annoying with the multiplexed address and data pins in the DIP-40: you have to demultiplex them with latches and transcievers. And don't forget the 8088 (used in the PC) couldn't do data in one clock due to the 8-bit data bus (386SX was similar in the next step up.) Pretty cool for us that the 8086/8 are breadboardable though.
- userbinator 5y ago
  They could've definitely put more shift registers on die and squeezed an 8086 in a DIP-16, but then the support circuitry would become even more complex. It's worth noting that the trend has been towards (high speed) serial buses in later CPUs, e.g. the Pentium 4 was the last generation to use a parallel FSB; that was replaced with the serial https://en.wikipedia.org/wiki/Direct_Media_Interface https://en.wikipedia.org/wiki/Direct_Media_Interface
  - guerrilla 5y ago
    Fair enough. I think the original Datapoint design for what became the 8008 was even entirely serial, including the memory. I guess I should have said it would have been exceptionally more annoying. It's hard enough to get a computer out of it. So it'd be impossible in the sense that they wouldn't have met the goal of getting that relatively easy kit out of it and there wouldn't have been any PC.
  - christkv 5y ago
    I think I remember that the reason we moved onto serial buses was due to the complexity of ensuring signal integrity for high speed signaling.
retrac 5y ago
The 8008, Intel's first 8-bit processor, direct ancestor to the 8080 and indirectly to the Z80 and 8086, also came in a far-too-small 18-pin package as well. In hindsight it seems rather inscrutable. Why were they hobbling their product like that? Well it seems just the arbitrary preference of one executive. But the seeming absurdity of it is partially an artifact of later thinking, from the era of single-chip microcontrollers. The 4004 and 8008 both needed a large amount of dedicated support electronics. Not just bus multiplexers, but clock drivers, special memory interfaces, etc. You couldn't turn an 8008 on without at least half a dozen support chips which were as much an integral part of the "computer" to the designers as the 8008 itself was. And while multiplexing brutally hindered the chip's performance, oddly enough pure performance doesn't seem to have been a major design goal for either the 4004 or 8008. Basically anything would be fast enough -- even multiplexed at 0.5 MHz -- for the industrial control and calculator-like applications envisioned.
- ido 5y ago
  I think that's the real answer - they simply didn't think better performance mattered/would be worth the extra cost/complexity.
  - leeter 5y ago
    Looking at the 8008 wiki if the quotes are to be believed they were actually scared of performance. Believing that they would scare off customers buying intel memory (their main business at the time apparently) for their own in house processors. So it seems very deliberate. That said the 8008 was primarily intended for terminals where performance really wasn't a concern. But that didn't stop people from making proper mini-computers from it.
- kjs3 5y ago
  According to Federico Faggin[1]: The 8008 used P-channel silicon gate MOS technology and was packaged in an 18-pin package: a very poor choice, imposed by Intel management’s aversion to high pin-count packages. [1]: http://www.intel4004.com/qa8008_8080.htm http://www.intel4004.com/qa8008_8080.htm
kens 5y ago
For details on how Intel was fixated on 16-pin chips, see the Oral History of Federico Faggin [1]. He describes how 16-pin packages were a completely silly requirement, but the "God-given 16 pins" was like a religion at Intel. He hated this requirement because it was throwing away performance. When Intel was forced to 18 pins by the 1103 memory chip, it "was like the sky had dropped from heaven" and he had "never seen so many long faces at Intel." [1] pages 55-56 of http://archive.computerhistory.org/resources/text/Oral_History/Faggin_Federico/Faggin_Federico_1_2_3.oral_history.2004.102658025.pdf http://archive.computerhistory.org/resources/text/Oral_Histo...

guerrilla 5y ago

I think it would have been impossible otherwise. It's still annoying with the multiplexed address and data pins in the DIP-40: you have to demultiplex them with latches and transcievers. And don't forget the 8088 (used in the PC) couldn't do data in one clock due to the 8-bit data bus (386SX was similar in the next step up.) Pretty cool for us that the 8086/8 are breadboardable though.

userbinator 5y ago
They could've definitely put more shift registers on die and squeezed an 8086 in a DIP-16, but then the support circuitry would become even more complex. It's worth noting that the trend has been towards (high speed) serial buses in later CPUs, e.g. the Pentium 4 was the last generation to use a parallel FSB; that was replaced with the serial https://en.wikipedia.org/wiki/Direct_Media_Interface https://en.wikipedia.org/wiki/Direct_Media_Interface
- guerrilla 5y ago
  Fair enough. I think the original Datapoint design for what became the 8008 was even entirely serial, including the memory. I guess I should have said it would have been exceptionally more annoying. It's hard enough to get a computer out of it. So it'd be impossible in the sense that they wouldn't have met the goal of getting that relatively easy kit out of it and there wouldn't have been any PC.
- christkv 5y ago
  I think I remember that the reason we moved onto serial buses was due to the complexity of ensuring signal integrity for high speed signaling.

retrac 5y ago

The 8008, Intel's first 8-bit processor, direct ancestor to the 8080 and indirectly to the Z80 and 8086, also came in a far-too-small 18-pin package as well. In hindsight it seems rather inscrutable. Why were they hobbling their product like that? Well it seems just the arbitrary preference of one executive. But the seeming absurdity of it is partially an artifact of later thinking, from the era of single-chip microcontrollers. The 4004 and 8008 both needed a large amount of dedicated support electronics. Not just bus multiplexers, but clock drivers, special memory interfaces, etc. You couldn't turn an 8008 on without at least half a dozen support chips which were as much an integral part of the "computer" to the designers as the 8008 itself was. And while multiplexing brutally hindered the chip's performance, oddly enough pure performance doesn't seem to have been a major design goal for either the 4004 or 8008. Basically anything would be fast enough -- even multiplexed at 0.5 MHz -- for the industrial control and calculator-like applications envisioned.

ido 5y ago
I think that's the real answer - they simply didn't think better performance mattered/would be worth the extra cost/complexity.
- leeter 5y ago
  Looking at the 8008 wiki if the quotes are to be believed they were actually scared of performance. Believing that they would scare off customers buying intel memory (their main business at the time apparently) for their own in house processors. So it seems very deliberate. That said the 8008 was primarily intended for terminals where performance really wasn't a concern. But that didn't stop people from making proper mini-computers from it.
kjs3 5y ago
According to Federico Faggin[1]: The 8008 used P-channel silicon gate MOS technology and was packaged in an 18-pin package: a very poor choice, imposed by Intel management’s aversion to high pin-count packages. [1]: http://www.intel4004.com/qa8008_8080.htm http://www.intel4004.com/qa8008_8080.htm

kens 5y ago

For details on how Intel was fixated on 16-pin chips, see the Oral History of Federico Faggin [1]. He describes how 16-pin packages were a completely silly requirement, but the "God-given 16 pins" was like a religion at Intel. He hated this requirement because it was throwing away performance. When Intel was forced to 18 pins by the 1103 memory chip, it "was like the sky had dropped from heaven" and he had "never seen so many long faces at Intel." [1] pages 55-56 of http://archive.computerhistory.org/resources/text/Oral_History/Faggin_Federico/Faggin_Federico_1_2_3.oral_history.2004.102658025.pdf http://archive.computerhistory.org/resources/text/Oral_Histo...