demystify the GuestPC card
ivelegacy (2674) 139 posts |
hi guys I’d like to know how the GuestPC card works in details, front both the Hardware and the Software point of view. Is there a good documentation ? Schematic ? Example ? Firmware ? Ok the PC/Pro’s sources are a piece of documentation, but I’d like to hear from you if there are a better sources. Thank you in advance |
Steve Pampling (1551) 7904 posts |
The are a number of useful documents, on many of the topics relating to old Acorn kit on this link here I forget the name of the document that describes the operation of the dual processor system architecture |
Theo Markettos (89) 919 posts |
The Open Bus specification in the Risc PC Technical Reference Manual (TRM) gives the bus description. Unfortunately it’s a fairly minimalist document. Basically it’s just a copy of the ARM 610 bus, with a tiny piece of arbitration logic (so either socket 0 or socket 1 can have the bus at a time). All the PC card stuff is in the Gemini ASIC, which isn’t publically documented. However the !PC source contains lots of details. There are also some details in the PC Card DDK (driver development kit) – this was NDAed back in the day, I’m not sure if it’s been released.
and the rest is ARM-side software. |
Steve Pampling (1551) 7904 posts |
I presume that would be the link on riscos.info |
ivelegacy (2674) 139 posts |
thank you guys for the informations, especially for the key-names in the sentence “Open Bus specification in the Risc PC Technical Reference Manual (TRM)” because It is exactly what I want and need to search with google =) It probably sounds like a crazy question, but Is it possible, in the theory, to plug an ARM610 CPU module in the PCCard slot ? |
ivelegacy (2674) 139 posts |
I found a few tech-docs (about other topics, but interesting) here and here and the RPC TRM document which provides a lot of useful informations |
Theo Markettos (89) 919 posts |
Yes, you can plug an ARM610 into the PC card slot. Five in fact. You can’t do it directly because you need the arbitration logic, which isn’t present on either card, and you probably want support for inter-processor interrupts. The other question, which Hydra doesn’t address, is the question of cache coherency between the two CPUs – since there’s no coherency logic in the CPUs, you need a mechanism to stop one accessing data which is held in the cache of the other and is stale in DRAM. I suspect Hydra did this with explicit flushing to ensure consistency, but the Hydra overview doesn’t say. That’s a good reference for understanding what multiprocessors have to do (without all the x86 cruft getting in the way). There are some other limitations. |
Wouter Rademaker (458) 197 posts |
Simtec seems a bit down: |
Steve Pampling (1551) 7904 posts |
A bit domain expired. Are they still in business? I know they moved to other things some years ago but ages comes to all and the owners may have sold up or retired or both. |
Steve Fryatt (216) 2040 posts |
Companies House says “Status: Dissolved 22/07/2014”. The domain expired on May 5th this year, according to Nominet.
The Simpsons weren’t that old, were they? |
Steve Pampling (1551) 7904 posts |
Sold up / closed down option then. Reminds me of roughly this time last year, seeing a familiar old name on a business premise in Shipley, wondering how many other names are out there not doing stuff for RO anymore. |
Chris Evans (457) 1614 posts |
Having spoken to a number of the Simpson family in the last year. I can relate that the various member of the family have gone there own ways. Gillian is now carrying on what was the rump of Simtec. It sounds like it may now be under a different trading entity. |
Rick Murray (539) 13350 posts |
Any hope of one obtaining the sources to IDEFS? It was a nice board (I have one, never let me down) and shouldn’t (in theory!) take much to make it 32 bit for the IOMD build of RISC OS 5. Of course, what happened to Gillian might have affected the business, so who knows where things may be. Hmm… |
ivelegacy (2674) 139 posts |
Hydra looks like an incredible kit :D do you know if someone still sell it ? |