Does anyone have any insights into the proprietary graphics buses that were being created leading up to the VESA Local Bus (as referred to in the article)? I was not aware of anything between 16-bit ISA and the addition of VLB.
Practically every Unix workstation had a different solution.
Part of their performance lead was a proprietary bus that was much faster than ISA.
Technically they weren't graphics busses but since scsi and networking were built in graphics cards were the only things that mattered when it came to the higher bandwidth. A typical Sun Sparcstation would have a graphics card and maybe a serial port card or something that didn't care about the bandwidth of SBUS.
People completely forget this but from the late 80s to the mid-90s (when PCI started becoming widely available) if didn't want to shell out for a Unix workstation and you stuck a fast Radius or Supermac video card in your Macintosh II, your desktop publishing/graphics editing/visualization workflow experience was astronominfinitely better than on PC even if its 486 was faster than the 68020/68030 in your Mac. When PCI came out Apple immediately switched.
Intel probably looked at NUBUS, SBUS, and all of the others and went "well shit if we don't do something about this the pentium won't matter because video cards will be stuck on either ISA or the jank-ass VLB".
Well, VLB wasn't limited to graphics... it was just a fast bus. As opposed to the much later AGP that afaik, was graphics only.
But, MicroChannel was IBM proprietary. I don't know if anybody else had enough market or enough full stack to make a proprietary bus viable; IBM was making graphics cards and motherboards (and cpus, sometimes), and selling enough units that it was worthwhile for add-in makers to support MCA.
VLB wasn't limited to graphics... it was just a fast bus.
VLB wasn't limited to graphics, but it had issues which made it difficult to use in other applications. Still, there were a handful of SCSI and Ethernet cards made to the standard.
The physical size (Very Long Bus!) meant that it was best suited to cards which were already going to be large (e.g. graphics cards with lots of memory chips) and the tight coupling to the system memory bus meant that it was hard to use with anything other than an 80486 CPU -- which inherently discouraged its use for peripherals which weren't firmly aimed at the consumer market.
Ultimately I think the story here is less "Intel undercut a standards process" and more "Intel realized that the standards process had produced a horrible design". We should be glad that they hedged their bets; PCI was far superior.
Note that AGP was initially basically just PCI 2.1, with the bus conflict resolution system ripped out, the connector flipped around and a few minimal tweaks. It could, in principle have been used for something other than a video card.
The crucial part about it was that it was a dedicated link to one device. AGP was initially created not because PCI bandwidth was running out, but because PCI is a shared bus, and the kind of transfers video adapters liked to do played havoc with the system that negotiated who had right of way, resulting in all kinds of problems when other cards had to wait for their turn for much longer than their driver developers expected.
The fact that it only ever connected one device to the host made it much easier to evolve, as future cards and hosts could just negotiate to do something different than what AGP 1.0 defined, if they found they both supported a faster version. When bandwidth demand rapidly rose with ever faster 3d accelerators, this was very beneficial.
In the PC space, as a disjointed semi-chronological overlapping timeline:
In the beginning, we had ISA. We had ISA because it was cheap enough for IBM's PC, not because it was good.
MicroChannel was a thing, largely limited to IBM, starting in 1987. It worked well.
EISA was a thing. It was not ever particularly common or cheap. It had 32-bit width and 8.33MHz bus speed, in 1989. EISA's main features were that it was solid, and that it was not MicroChannel. It was backwards-compatible with ISA cards.
Then VLB happened. It was fast, 32-bit, was often flaky, and it was cheap. It was very popular for all kinds of PC accessories -- not just video cards.
Then, of course: Everything performance-oriented shifted to 32-bit PCI almost overnight (including some things outside of the PC space).
But there as also a time when we had PCI-X (which is absolutely not an abbreviation for PCI Express). PCI-X was 64-bits wide at up to 133MHz (though 66MHz was more typical). Like EISA, it never became common or cheap.
And eventually, we had AGP -- but only for graphics.
And there was also PCI-X 2.0, which was like the previous version was 64-bits wide, but it could operate at up to 533MHz. It was theoretically excellent, but essentially never really existed: Widespread PCI Express adoption was right around the corner by then.
And now, of course: We have PCI Express, which we've been successfully flogging along in various incarnations for a couple of decades -- a damned eternity in computer years.
snakeyjake|1 year ago
Part of their performance lead was a proprietary bus that was much faster than ISA.
Technically they weren't graphics busses but since scsi and networking were built in graphics cards were the only things that mattered when it came to the higher bandwidth. A typical Sun Sparcstation would have a graphics card and maybe a serial port card or something that didn't care about the bandwidth of SBUS.
People completely forget this but from the late 80s to the mid-90s (when PCI started becoming widely available) if didn't want to shell out for a Unix workstation and you stuck a fast Radius or Supermac video card in your Macintosh II, your desktop publishing/graphics editing/visualization workflow experience was astronominfinitely better than on PC even if its 486 was faster than the 68020/68030 in your Mac. When PCI came out Apple immediately switched.
Intel probably looked at NUBUS, SBUS, and all of the others and went "well shit if we don't do something about this the pentium won't matter because video cards will be stuck on either ISA or the jank-ass VLB".
toast0|1 year ago
But, MicroChannel was IBM proprietary. I don't know if anybody else had enough market or enough full stack to make a proprietary bus viable; IBM was making graphics cards and motherboards (and cpus, sometimes), and selling enough units that it was worthwhile for add-in makers to support MCA.
cperciva|1 year ago
VLB wasn't limited to graphics, but it had issues which made it difficult to use in other applications. Still, there were a handful of SCSI and Ethernet cards made to the standard.
The physical size (Very Long Bus!) meant that it was best suited to cards which were already going to be large (e.g. graphics cards with lots of memory chips) and the tight coupling to the system memory bus meant that it was hard to use with anything other than an 80486 CPU -- which inherently discouraged its use for peripherals which weren't firmly aimed at the consumer market.
Ultimately I think the story here is less "Intel undercut a standards process" and more "Intel realized that the standards process had produced a horrible design". We should be glad that they hedged their bets; PCI was far superior.
Tuna-Fish|1 year ago
The crucial part about it was that it was a dedicated link to one device. AGP was initially created not because PCI bandwidth was running out, but because PCI is a shared bus, and the kind of transfers video adapters liked to do played havoc with the system that negotiated who had right of way, resulting in all kinds of problems when other cards had to wait for their turn for much longer than their driver developers expected.
The fact that it only ever connected one device to the host made it much easier to evolve, as future cards and hosts could just negotiate to do something different than what AGP 1.0 defined, if they found they both supported a faster version. When bandwidth demand rapidly rose with ever faster 3d accelerators, this was very beneficial.
zdw|1 year ago
There was also the VGA "feature connector" which was used sometimes for video capture, mpeg decoders, and so on: https://en.wikipedia.org/wiki/Feature_connector
chasil|1 year ago
https://en.m.wikipedia.org/wiki/NuBus
SPARC also had sbus, but this is likely later than your window.
https://en.m.wikipedia.org/wiki/SBus
jbit|1 year ago
Opti local bus was the most common, and had a few different boards: https://ancientelectronics.wordpress.com/tag/opti-local-bus/
Gigabyte had one that was only used for the "GA-486US" motherboard. The connector was just two 16bit ISA cards back to back: https://theretroweb.com/motherboard/image/ga-486us-front-60b...
I believe there were some others from different vendors.
The signaling for all of these was pretty similar to VLB, since it was just the 486 bus on a connector.
ssl-3|1 year ago
In the beginning, we had ISA. We had ISA because it was cheap enough for IBM's PC, not because it was good.
MicroChannel was a thing, largely limited to IBM, starting in 1987. It worked well.
EISA was a thing. It was not ever particularly common or cheap. It had 32-bit width and 8.33MHz bus speed, in 1989. EISA's main features were that it was solid, and that it was not MicroChannel. It was backwards-compatible with ISA cards.
Then VLB happened. It was fast, 32-bit, was often flaky, and it was cheap. It was very popular for all kinds of PC accessories -- not just video cards.
Then, of course: Everything performance-oriented shifted to 32-bit PCI almost overnight (including some things outside of the PC space).
But there as also a time when we had PCI-X (which is absolutely not an abbreviation for PCI Express). PCI-X was 64-bits wide at up to 133MHz (though 66MHz was more typical). Like EISA, it never became common or cheap.
And eventually, we had AGP -- but only for graphics.
And there was also PCI-X 2.0, which was like the previous version was 64-bits wide, but it could operate at up to 533MHz. It was theoretically excellent, but essentially never really existed: Widespread PCI Express adoption was right around the corner by then.
And now, of course: We have PCI Express, which we've been successfully flogging along in various incarnations for a couple of decades -- a damned eternity in computer years.
unknown|1 year ago
[deleted]
sedatk|1 year ago
WarOnPrivacy|1 year ago