cpb@doc.ic.ac.uk (C P Brown) (01/17/91)
I have a CSA Mega Midget Racer on order for my A500. I wonder if anyone can answer these questions for me: The 4Mb of 32-bit RAM is Addmemmed (or equivalent). Is there a way of booting up into Wb as normal so that the memory is added to the system map, and then saying something like "reboot from floppy, but remembering your added memory"? I want to do this so that games like Indy 500 will operate from fast 32-bit RAM, rather than the 16-bit stuff which will be the case if I just boot normally. I saw an '020 board which had a resident program to automatically do the addmem on reboot, but it had the side effect of trashing the A590 rigid disk block (ie unusable). The system I ordered is 25MHz, to what extent can I crank this up by overclocking? The design is async so no problem there. Maybe 28MHz? 30? Someone I know has clocked an '040 at 42MHz, no timing problems... Has this board been released in the US? Over here they are dirt cheap for what you get (25MHz 68030, 68882 + 2Mb RAM is about $1000). Thanks in advance. Phil -------------------------------------------------------------------------------- With the advent of OS/2 and MultiFinder, I'd like to welcome the PC and Mac users into the world of multitasking. Unfortunately I can't. Keep on trying guys--------------------------------------------------------------------------------
lkoop@pnet01.cts.com (Lamonte Koop) (01/19/91)
cpb@doc.ic.ac.uk (C P Brown) writes: > >I have a CSA Mega Midget Racer on order for my A500. I wonder if anyone can >answer these questions for me: > >The 4Mb of 32-bit RAM is Addmemmed (or equivalent). Is there a way of booting >up into Wb as normal so that the memory is added to the system map, and then >saying something like "reboot from floppy, but remembering your added memory"? >I want to do this so that games like Indy 500 will operate from fast 32-bit >RAM, rather than the 16-bit stuff which will be the case if I just boot >normally. I saw an '020 board which had a resident program to automatically >do the addmem on reboot, but it had the side effect of trashing the A590 rigid >disk block (ie unusable). Hmmm...I believe the '020 board you are referring to is the Hurricane 500. I suppose it might be possible to set up a resident structure to do this, but as far as games and the sort are concerned, most of those will dump the OS in favor of their own methods of using the system, so this may be a moot point. Now, if a game comes on a floppy which boots normally, (eg..startup sequence and all), you can always add the appropriate portions to that startup sequence. Now, if you are REALLY into some heavy hacking, and have no problems with the idea of trashing your game disk, you could try to write a boot block (after deciphering the original, to get all of that down) that will vector off into a routine to add the memory...or perhaps an existing resident structure. However, most of this work might be fruitless, as many games simply do not work properly with '030s in the first place. >The system I ordered is 25MHz, to what extent can I crank this up by >overclocking? The design is async so no problem there. Maybe 28MHz? 30? >Someone I know has clocked an '040 at 42MHz, no timing problems... Timing isn't the problem. I am familiar with the MMR setup, and you won't run into any problems with the rest of the board, but if you are using an '030 rated for 25MHz, that will be your limiting factor. Now, as to how much you can overclock it, that is quite variable. There is a certain amount of leeway involved here (In fact, once at temperature, I'd expect the true clock through the '030 at 25MHz to be closer to 28MHz), but eventually you will have problems. Putting in a 28MHz oscillator may work ok (no promises)...but I probably wouldn't push it beyond that...you might have a chip which is tolerant, and then again you might not. Another point to consider: How fast is the DRAM you have? If you are at 80ns, the CSA board is setup in such a way that you can conceivably get away with 1 wait on the memory bus (it's close...but can be done)...same for the SRAM area. If you go to 28 or 33MHz, you will assuredly have to add additional wait states. Now, for a large jump in speed, those extra waits will be offset, but if you jump to 28MHz, and go to 2 waits, you may negate a portion of your increase in speed with the extra wait. LaMonte Koop Internet: lkoop@pnet01.cts.com ARPA: crash!pnet01!lkoop@nosc.mil UUCP: {hplabs!hp-sdd ucsd nosc}!crash!pnet01!lkoop A scientist is one who finds interest in the kinetic energy of Jell-O moving at ridiculous velocities...an engineer is one who can find a real-life application for such silliness.