LWELCH@COLGATEU.BITNET (03/19/89)
From: EDU%"m2c!wpi!dseah@HUSC6.HARVARD.EDU" "David I Seah" 13-MAR-1989 17 :51:20.63 Subj: Re: GS specific programs >What I dont understand is if processing the minimal bitmap slows down this >machine so much, then why in heaven's name are all those other machines which >process bitmaps so fast? Is it perhaps not so much the bitmap, but the >code that is DOING the refresh / manipulation the thing that is slow? Or >is it indeed that the HARDWARE implementation of the bitmap subsystem that >is designed to run so slowly? I am just trying to understand. I have Larry, the Apple IIGS graphics screens reside in "slow RAM". The memory devices involved can read/write data at the old 1Mhz speed of the Apple II+. So, everytime you try to put something on the screen, the 65816 gets slowed down from 2.8MHz (assumption) to 1Mhz during those write cycles to the video buffer. The IIGS super hires video buffer is also 32K in size, 4x the size of I am interested too in why the GS graphics hardware is so...limited. I have been told that, "Oh, the slowdown is requires to maintain compatibility with mumble mumble", but no-one tells me why. My guess is that the Mega II was incapable of running at higher speeds. Why use 1MHZ DRAMs anyway unless the Mega II couldn't handle anything faster? ------------- I seem to recall that the //GS must slow down to 1MHz when displaying graphics to maintain compatibility with the 1MHz rate of the monitors. Does anyone know the reason for the //GS slowing down for graphics? Is there any way to speed up the display of graphics on the //GS without simply increasing the clock speed with a Transwarp? If the graphics could be displayed at 2.8 MHz instead of 1MHz, there would be a tremendous improvement in Desktop applications. | Chip Welch "Apple ][ Forever!" | | Chipmunk Computer Systems | | CU Box L3058 BITNET: LWELCH@COLGATEU.BITNET | | Hamilton, NY 13346 GEnie: CWELCH3 | `----------------------------------------------------------------------------'