czei@osupyr.UUCP (Michael S Czeiszperger) (09/09/87)
This probably was discussed previously, but here it goes:
I'm trying to figure out the effects of adding a 24 bit
buffer card to our mac II. Is the memory needed for video
taken from regular virtual memory, or is it contained
on the card? Since a full screen image at 24 bits would
probably fill up about 2.25 meg, the addition of the
higher resolution board would contain the hidden costs of
higher memory requirements.
Michael S. Czeiszperger | Disclaimer: "Sorry, I'm all out of pith"
Sound Synthesis Studios | Snail: Room 406 Baker Phone: (614)
College of the Arts Computer Lab | 1971 Neil Avenue 292-
The Ohio State University | Columbus, OH 43210 0895
UUCP : {decvax,ucbvax}!cbosgd!osupyr!czeiolson@endor.harvard.edu (Eric Olson) (09/10/87)
In article <162@osupyr.UUCP> czei@osupyr.UUCP (Michael S Czeiszperger) writes: >This probably was discussed previously, but here it goes: >I'm trying to figure out the effects of adding a 24 bit >buffer card to our mac II. Is the memory needed for video >taken from regular virtual memory, or is it contained Picky point: No virtual memory on the Mac II (Yet). >on the card? Since a full screen image at 24 bits would >probably fill up about 2.25 meg, the addition of the >higher resolution board would contain the hidden costs of >higher memory requirements. A 24-bit card does not use any more main memory per se, however, applications that build off-screen PixMaps (images) that match the current maximum screen depth would consume more memory (assuming the card is actually set to run in 24-bit mode). The actual screen memory is on the card, and not available to anything but the video card. The only people I know of that are even planning 24-bit video is SuperMac (makers of the pretty, big, SuperMac 8-bit color display for the Mac II). I think they're going to do it by using 3 of their 8-bit cards. -Eric Eric K. Olson olson@endor.harvard.edu harvard!endor!olson
czei@osupyr.UUCP (Michael S Czeiszperger) (09/11/87)
In article <2819@husc6.UUCP> olson@endor.UUCP (Eric Olson) writes: >>taken from regular virtual memory, or is it contained > >Picky point: No virtual memory on the Mac II (Yet). > I'm guilty of using the term virtual memory without knowing it's exact definition. I've designed and built video memory addressing schemes for small microprocessors, but havn't ever worked with an operating system to know the difference between memory that is read by the video chip, memory that contains cpu instructions, and memory that is used to store data. Could someone clarify this point? Michael S. Czeiszperger | Disclaimer: "Sorry, I'm all out of pith" Sound Synthesis Studios | Snail: Room 406 Baker Phone: (614) College of the Arts Computer Lab | 1971 Neil Avenue 292- The Ohio State University | Columbus, OH 43210 0895 UUCP : {decvax,ucbvax}!cbosgd!osupyr!czei