> Just a few more thoughts on s/w and h/w... > > What sort of OS are you thinking of putting into the S^2? Obviously it's > got to be SAM compatible - by swapping in a new ROM, copying it into RAM or > what?
ROM swapping is the trick that I'm going to use... it's SAM compatible in the way that the normal ports on the ASIC are going to be used as "transfer ports" -- ie they don't access the chips direct any more, but get stuffed into latches for the appropriate other z80's to handle it.. only in SAM emulation mode though. The OS will be a DOS, with extension files on disc to hook it and bodge it if necessary -- if we can, we'll use EEPROMs so that upgrades can be freebies.. > But is the new machine going to jump straight into BASIC like SAM does, or > into a CLI or even a (shock, horror) GUI? I'm for the CLI, as you can do > whatever you like once you're there, tho that would mean you'd have to write > a fairly comprehensive OS if it's going to be any good. It'll probably be a menu, with a *really* fancy screen, and a choice of either 1) SAM, 2) CLI, 3) GUI or 4) BASIC... of course, using the CMOS battery-backed BIOS ram (in the keyboard processor section), you'll be able to make it start up in any mode you want -- AUTOMATICALLY--. That's apart from bog-standard SAM mode, which you will have to SAY you want :) Possibly. It's just a matter of switching the appropriate ROM in really... there may be ways around it. > Pre-emptive multi-tasking would be nice, tho things start getting tricky > when you do that. Co-operative is easier, but not nearly so nice. (Anybody > out there who _likes_ windoze?) I do. It's better than nothing. But only since it has Truetype fonts (anyone got the docs for them, btw?) > Hardware scrolling and sprites would be _good_, but not perhaps essential. > I think the scrolling is more important - if you take Amiga games, for > example, most of them scroll the screen, but rather less use the h/w > sprites, as they're not quite as useful as they sound on the cheap (non AGA) > machines, since they are a tad limited, particularly in size and colours. mmmm.... have to see what I can do... > >From what I can gather, DMA is very handy, but only if you've got lots of > custom chips, like the Amiga, so I guess it's not essential, as I don't see > you designing lots of custom graphics & sound chips... > > I think I said before about sound - make sure it's easy to use. Programming > the SAM's sound chip is a bit of a nightmare. Well... I'm going to get Stefan to write the MOD Player for the sound processor -- it'll be the exact same code as it is now, but sync'd in a different way, and in ROM with Sample player code, and Etracker player code (or something similar -- have to talk to Mat about that :) ). The Sound unit will work in this way: 32k ROM, 256k RAM, paged as ROM 0-32767, RAM 32768-49151, 49152- 65535, switched in 16k chunks. Z80 (20MHz), with CTC chip to handle rates and stuff... also handshaking and XMEML access protocols to rest of the system. 256k sound ram will appear as Meg 4, pages 0-15, Gig section 0. Wired to 4x8-bit DACs, 2 left, 2 right. volume controlled in s/ware. > Oh well, there's my little contribution. > > Bye > Nige Si +----------------INTERNET: [EMAIL PROTECTED] | When walking a tightrope made of razor-blades, be very careful -- | | you won't be able to grab hold of it if you fall. (Si Cooke, '94) | +------------------JANET: [EMAIL PROTECTED]
