Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!waikato.ac.nz!canterbury!otago.ac.nz!michael
Newsgroups: comp.sys.mac.hardware
Subject: Re: 32-bit video for the LC/si
Message-ID: <1991May2.093045.350@otago.ac.nz>
From: michael@otago.ac.nz
Date: 2 May 91 09:30:45 NZDT
References: <2599@optima.cs.arizona.edu> <1448@radius.com> <2649@optima.cs.arizona.edu>
Organization: University of Otago, Dunedin, New Zealand
Lines: 25

In article <2649@optima.cs.arizona.edu>, gerhard@cs.arizona.edu (Gerhard Mehldau) writes:

> But doesn't the LC need to have such a DAC already, if it can display
> 16-bit color for the small screen?  With the appropriate amount of VRAM,
> it should be able to handle at least 16-bit color for larger screens
> at well.  No?

Evidently the LC has a DAC that can (at least) go into a mode where it gets 5
bits per channel direct from the incoming stream from RAM rather than
indirectly from a lookup table. Presumably the only thing preventing it from
doing more is bandwidth limitations on the rate it can read from RAM.

This leads to another interesting question; why can't the IIsi do 16-bit video?
Or to put it another way, could it acquire such an ability in the future? It
has a megabyte of RAM to use for video and a 16-bit 640*480 colour display
would use 614K. Perhaps the CPU would have too little bandwidth to the video
RAM left to provide acceptable update performance. In which case you have to
wonder if a version of the IIsi with VRAM instead of standard DRAM for the
video is in Apples plans.

Michael(tm) Hamel, Computing Services Centre, University of Otago, New Zealand

UDINE (adj.)                       
Not susceptible to charm.