hassell@tramp.Colorado.EDU (Christopher Hassell) (02/07/89)
y00VQDE5W1ha@andrew.cmu.edu> jm7e+@ANDREW.CMU.EDU ("Jeremy G. Mereness") writes: # # This is a techinical question to Keith, Doug, Murph, or whoever can make sense # of this to me... # >Excerpts from ext.in.info-apple: 3-Feb-89 Re: The Future of the Appl.. David I # Seah@relay.cs.ne (2215) # # > I'd like to see a # >copy memory-to-memory device supported for blisteringly fast data transfers # >with no speed limits to maintain "video compatibility". (Can someone explain # >to me just WHY the clock must be 1Mhz to maintain compatibility? Is it the # >same Woz-designed hardware in a new package? Is the Mega II in its current # >form just too slow to handle a fast system clock?) # # Why is this? I have been wondering specifically what timing is so critical and # whether there is any way to alleviate it. Especially considering the transwarp, # it seems crazy that a 7MHz machine has to slow down by a factor of 7 every time # it writes to the screen. Can't a buffer be created? Is the slowdown only # critical for emulation mode (where the system could maybe be set to bypass the # slowdown when in 16-bit mode) or is there something more fundamental? As # processor speed increases, this shadowing delay will become more obvious a # bottleneck... That is because apple wants compatibility with CARDS! Remember its NOT only the GS that fools around with its guts. Cards can do stuff with graphics memory TOO. They decided that if ANY compatibility was maintained then there is not enought reason to put in TWO separate speeds of accessing a patch of memory. Besides, slower chips are still cheaper. # The same author mentioned an idea that has puzzled me for a while; why does # Apple not create a Quickdraw Co-processor? What would be the # advantages/disadvantages considering the protocol is already existent and # resident in hardware ROM anyway, and it would save the CPU from tons of work.... I'm positive that it is because Apple has the VERY-unique and QUITE laudible principle of keeping-things-in-software. A coprocessor USUALLY is simply a spedupfastgraphicscommandprocessor and NOTHING else. This is similar to the Amiga Blitter and Copper though the copper has its own "memory" to run its wierd command set (used to change screen configs). # Capt. Albatross # jm7e+@andrew.cmu.edu # # ============ # Bureuacracy takes all the fun out of computing. # disclaimer: The opinions expressed herein are made under duress of academic # stress and is often prone to overzealous error. The author, not enjoying the # prospect of remaining eternally ignorant, therefore welcomes any replies that # would further that end. Beauracracy DOES take fun out of computing. But you do have to please alot of the people alot of the time. ### C>H> ###