andras@alzabo.ocunix.on.ca (Andras Kovacs) (05/06/91)
Would someone(s) please explain the differences between various MEMCs? Thanks, Andras -- Andras Kovacs Artech Digital Entertainments andras@alzabo.ocunix.on.ca (613) 563-4746 Nepean, Ont. Ottawa, Ontario, Canada
dbh@doc.ic.ac.uk (Denis Howe) (05/07/91)
And while we're on the subject of MEMC, can anyone say exactly what the effect of the memc_roms program on the Newcastle server is? It sets the MEMC speed (cycle time) for the ROMs to, what my VLSI data book says is "Not Meaningful" but which extrapolation from the other possibilities (450, 325, 200ns) would suggest is actually 75ns. It does produce a speed-up (~25% for FOR I%=0 TO 10000:NEXT ) and doesn't seem to crash my A410. Am I just lucky? -- Denis Howe <dbh@doc.ic.ac.uk> C-C H558A Imperial College London C-C-C +44 (71) 589 5111 x5064 N=N
gilbertd@p4.cs.man.ac.uk (Dave Gilbert) (05/07/91)
OK - lets start with different MEMCs. The one in the original A310's, and A440's was the MEMC 1 - the story I was told was that it had a bug somewhere, and a bit of logic on the PCB was needed to kludge it into working - this resulted in a degredation of speed by about 10% - when they finaly bought out the A400/1 series the MEMC1a was born - fixing the original problem and so we could all run that little bit faster - the difference is easily noticable - I use both a 310 and a 420/1 - the speed is noticably different on some of the programs I use. There is a rumour that there is a MEMC 2 - which is supposed to be able to have varying page sizes - a lot better really. As for ROM speeds - well all us people who don't have A540's and R260's run our ARM and memory at 8MHz - but the ROMS aren't guarenteed to run at 8MHz, only 4MHz - so when you access your ROMS the MEMC slows everything down to 4MHz and then up again when you access everything else - hence the RMFASTER command which shifts modules from ROM to RAM and these little programs which tell the MEMC that your ROMS can run faster. I would really be grateful if someone could explain why after the semi conductor industry has made fast RAM possible at a reasonable price why ROMS are so difficult. Dave -- ------------------------------------------------------------------------------- - Dave Gilbert - gilbertd@p4.cs.man.ac.uk - The MTBF of a piece of equipment - - G7FHJ@GB7NWP - is inversly proportional to its - ------------------------------------------- importance -