5 ms·
Reverse engineering a forgotten 1970s Intel dual core beast: 8271 (2020)
- ChrisArchitect 3y ago(2020) Some discussion then: https://news.ycombinator.com/item?id=25115916 https://news.ycombinator.com/item?id=25115916
- mrlonglong 3y agoI think Acorn made a big mistake using those chips for their floppy disk drives, they were expensive and availability was not good.They should have used the WDC1770 instead but that's life.
- tom_ 3y agoAcorn did figure this out eventually and used the 177x from about 1984.
- mrlonglong 3y agoThe 1772, yes. I had at the time a 1770 from Solidisk.
- deleted 3y ago[deleted]
- rasz 3y agoAcorn was badly mismanaged. BBC Micro Computer Literacy Project was the best marketing any money could buy, and yet Acorn still managed to not be able to keep up with BBC royalties while selling tons of BBC Micro/Master computers.
- flohofwoe 3y agoI only know the Intel 8272 a bit (via the NEC uPD765 floppy controller in the Amstrad CPC), but what's fascinating about those old-school floppy controller chips is how high level their "API" is and how autonomously they operate. The chip accepts commands like "seek to track xyz", "format track", "read track", or "read or write a range of sectors", and the chip would go ahead and do its thing (with data transfers optionally via DMA - but this isn't supported in the CPC) and a couple of seconds later it would tell you "ok I'm done", or "oops I encountered this error". One would rather expect this sort of functionality implemented in a high level operating system function or in some sort of software driver instead of baked into hardware. This also explains the chip's complexity I guess (e.g. 22k transistors, 6x more than a 6502 and 2.5x more than a Z80) - because it actually is a fullblown CPU with a microcode ROM and some floppy controller bits tacked on the side ;)
- Maakuth 3y agoI believe this is one of the insights Steve Wozniak had that allowed them to make Apple // hardware a lot simpler and cheaper than the competition. They implemented this sort of stuff in the operating system. Commodore had these complicated chips too - for example the 1541 disk drive had the same 6502 CPU as the C64! They were able to compete on the price in the 80s by the virtue of owning their chief chip supplier, MOS Techonology.
- lostemptations5 3y agoI guess it depends on rhe application. Sometimes for speed to market and engineering simplicity the Intel solution is pretty good - though obviously eccentric. Not everyone has a Woz sitting around in their pocket.
- rjsw 3y agoThe API to the floppy disk in the Mac IIfx/Q900/Q950 range is at a similar level, it is implemented in one of the IOP coprocessors.
- justsomehnguy 3y agoIt's even more funny on some 386/486 boards, anyone unfamiliar on how they looks would never guess the CPU right, eg: http://www.amoretro.de/2012/05/386sxa-ver-4-0-motherboard-mit-am386sx-40-mhz-cpu.html http://www.amoretro.de/2012/05/386sxa-ver-4-0-motherboard-mi... https://theretroweb.com/motherboards/s/ampro-little-board-486slc-ii https://theretroweb.com/motherboards/s/ampro-little-board-48...
- colanderman 3y agoThat's about the same level of autonomy modern disk controllers provide. Commodore disk drives on the other hand were more high level. They operated at a level closer to that of a file server, and would field commands such as "list the directory". The DOS ran on the drive itself.
- dboreham 3y ago
- Donaldzibe 3y ago[flagged]