Search found 381 matches

by Pr0f
Mon Jun 03, 2019 1:01 pm
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 5736

Re: Asymmetric multiprocessing...

This shared RAM idea could be a good way of separating out mundane hardware control from the main CPU and it's jobs workload, allowing offloading of a lot of the I/O tasks

Taking the idea of the IPC interface and growing out to something much bigger and extensible ?
by Pr0f
Mon Jun 03, 2019 11:55 am
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 5736

Re: Asymmetric multiprocessing...

so where is this thread going?
by Pr0f
Thu May 30, 2019 6:41 pm
Forum: Hardware
Topic: Symmetric multiprocessing...
Replies: 52
Views: 5090

Re: Symmetric multiprocessing...

you can use the FC0-FC2 to signal a fetch of restart vector - as it's different to other vector fetches - and could remap the dual port ram when a reset is done on the off board processor, but otherwise leaving it alone.
by Pr0f
Thu May 30, 2019 9:32 am
Forum: Hardware
Topic: Symmetric multiprocessing...
Replies: 52
Views: 5090

Re: Symmetric multiprocessing...

This reminds me of the propeller a little bit, which might be an interesting way to realise this ;-) So you have 8 equally powerful cpu's sharing some common ROM / RAM and having some private RAM. One would arbitrarily manage the startup of the system, then each could be engaged or disengaged as nee...
by Pr0f
Sat May 25, 2019 7:28 pm
Forum: Hardware
Topic: Gold Card info request.
Replies: 3
Views: 405

Re: Gold Card info request.

Dave,

Address lines A21, A22 and A23 are not connected to anything on the board, so my guess is the 2Mb will repeat through the address space.

That's from the original circuit diagram and also confirmed on the Tetroid Gold card.
by Pr0f
Fri May 24, 2019 8:24 pm
Forum: General QL Chat
Topic: Sad news
Replies: 4
Views: 717

Re: Sad news

RIP

I remember SPEM
by Pr0f
Fri May 24, 2019 9:09 am
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 5736

Re: Asymmetric multiprocessing...

by Pr0f
Fri May 24, 2019 9:03 am
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 5736

Re: Asymmetric multiprocessing...

The hardware for an Tube “interface” does not even need a DPRAM. The hardware of the second processor does all the hard work. The Tube “interface” or port is just buffered address and data busses. Plus some control lines. Like this: Address lines A0 to A2 (A0 to A6 are present on the BBC B and Mast...
by Pr0f
Thu May 23, 2019 9:18 am
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 5736

Re: Asymmetric multiprocessing...

The hardware side is quiet simple - it's Dave's dual port RAM idea. But the software - that's a different thing all together.

But the tube I/o or memory map is quite well defined, so it should be possible to create the equivalent calls and interfaces for Qdos
by Pr0f
Thu May 23, 2019 7:36 am
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 5736

Re: Asymmetric multiprocessing...

How much work would be involved in doing a 'Tube' like the BBC ? There is even an option to have a raspberry pi zero as tube add on, all be it with bespoke code running.