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From: midkiff@portia.Stanford.EDU (Neil Midkiff)
Newsgroups: comp.sys.mac.misc
Subject: Re: Graphics question
Message-ID: <1990Aug24.045722.21631@portia.Stanford.EDU>
Date: 24 Aug 90 04:57:22 GMT
Sender: midkiff@portia.Stanford.EDU (Neil Midkiff)
Distribution: usa
Organization: AIR, Stanford University
Lines: 21

In article <1211@meaddata.mead.UUCP> mead!rubin@uccba.uc.edu writes:
>I have a couple of technical questions..
>
>How does a computer generate the video representation of screen memory?
>
>How does a computer update the memory that is used for the screen?
>
>I was thinking and I got stuck when I thought about a 25Mhz (fast!)
>processor.  It seems to me that a the most memory that this processor can
>update at 60Hz or 60 times a second (which if I am not mistaken is
>the speed that a television redraws its picture and monitors are even faster)
>is only .417 Megabytes???
>
>Is this correct - the most graphical data that you can malipulate is less
>than 1/2 of a Meg at the normal speeds of a typical television when you
>are using a 25Mhz processor dedicated to graphics?  Is there something that
>I am missing - perhaps there is some sort of co-processor or something.
>Anybody out there who knows something about microprocessors ect..  please
>help me out..........
>
>Thanks in Advance					- Dan Rubin