Status: looking for testers
I've finally figured out a design I'm happy with for this -- posting here to see if anyone else would be interested in one.
This will be a board that plugs in to the four ROM sockets on an A3000, and act like a DualOS/MultiOS board, plus let you flash new versions of RISC OS (or old versions... so you could have a machine that'll boot up with Arthur, RO2, RO3, the test ROMs, your own RO build...) over USB without having to open the case.
- 16MB of flash memory, so you can store 4-8 different OS ROMs at once (4 x 4MB or 8 x 2MB).
- In-system programmability -- you'll be able to connect your Arc up to a laptop via USB, and update the OS images while it's running (or powered down)
- SYS "OS_UpdateMEMC", 64, 64 support, even under RISC OS 3, for some extra speed
- Maybe support for other 4-ROM machines, although I only have A3000s here to test with.
- The ability to make 4MB of flash visible to the machine by wiring in the A21 line, so you can fit more stuff in your RISC OS build
- MAYBE a fast USB serial port for off-machine communications (HostFS maybe?) using the extra address space, if I can fit this into the CPLD
Cost will be about $100 (£78) assembled including shipping worldwide; a bit less if you're in the USA, and there'll maybe be a kitset version for a bit less than that, although that's looking less likely right now as it'll have several BGA chips, which aren't easy to solder.
Caveat of course here is that I might not actually finish the project, but if I do, it'll be more or less as above
UPDATE: Keeping track of who's interested (from replies to this thread) - I'll confirm all this before actually ordering anything; this is just to give me an idea of who to talk to when I do have something working.
- IanS - one or more
- hubersn - 1 of the A310 type (has carrier board), 3 x A3000 (most important), 2 x A5000 type, 2-5 x Risc PC.
- paulv - one
- trixter - one (assembled)
- lcww1 - one
- JonC - 1 x A3000, 1 x A3020, 2 x A5000 (1's an Alpha), 1 x A440, 2 x A310, 1 x RISCPC
- 1024MAK - one or more for A5000, A30x0, A7000/Risc PC.
- Cutter - 1 x A3000
- markrwj - 1 x A3000
- Nutter - 1 x A3000
- sirbod - 1 x A305 (later: A440/1, A4000 and A5000)