Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!dali.cs.montana.edu!caen!sol.ctr.columbia.edu!emory!hubcap!ncrcae!ncr-sd!se-sd!cns!dltaylor
From: dltaylor@cns.SanDiego.NCR.COM (Dan Taylor)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: AMIGA
Message-ID: <937@cns.SanDiego.NCR.COM>
Date: 8 May 91 00:14:01 GMT
References: <1991May5.185506.5004@cunixf.cc.columbia.edu> <1991May5.212810.28755@wam.umd.edu> <1991May6.115535.8982@sugar.hackercorp.com> <1991May6.164821.8807@cunixf.cc.columbia.edu>
Distribution: usa
Organization: NCR Corp. SE-San Diego
Lines: 22

In <1991May6.164821.8807@cunixf.cc.columbia.edu> es1@cunixb.cc.columbia.edu (Ethan Solomita) writes:
>	I'm afraid your hard drive is a tad faster than mine. My
>Quantum can read slightly greater than 1MB/sec I believe if it is
>nice and contiguous, but if each frame is 32K then that makes
>1920K/sec. However, 60fps is irrelevant. 30 and 24 are far more
>meaningful. 

Most Amiga animations are stored in a format that does NOT require a
complete copy of EACH frame image, rather, deltas between frames are
used whenever possible, usually within a "scene".  Between the CPU
and the graphics coprocessors, it is easily possible to update the
next frame, then use the "copper" to switch at vertical sync.  I think
the real numbers are more like 60 "fields" per second, which is the
30 frames per second you mentioned.

Our disks can sustain near-megabyte per second throughput, but I haven't
seen one, myself, that can sustain 2 mbs through the file system.  The
original ZorroII, as in the A2000 family, has a (roughly) 4 mbs data
rate, so it IS possible to run the 2 mbs of disk data, and handle the
overhead.

Dan Taylor