Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!cornell!uw-beaver!fluke!ssc-vax!dmg
From: dmg@ssc-vax.UUCP (David Geary)
Newsgroups: comp.sys.amiga
Subject: Re: 1024X800 Monitor
Keywords: How much memory?
Message-ID: <2138@ssc-vax.UUCP>
Date: 2 Aug 88 15:42:13 GMT
Organization: Boeing Aerospace Corp., Seattle WA
Lines: 48

In article <1779@vu-vlsi.Villanova.EDU> Wilson Cheung writes:

>	This 1024x800 black and white monitor that Commodore plans to release
>sounds exciting, especially since it will work with my A1000.  However,
>my concern is the amount of CHIP RAM this is going to hog up.  My understanding
>is that it will need eight 640x400, 4-bit plane screens.  Will this hog
>up all 512K of standard CHIP RAM, so that multi-tasking will be out of the
>question?


  I don't think that a 1024X800 black and white monitor will use 640X400
bitplanes.  For black and white, you'd only need ONE 1024X800 bitplane.  In
terms of how much memory one 1024X800 bitplane takes up:

1)  Each byte contains 8 bits.  Therefore, one byte represents 8 bits in
    the bitplane:

    1024 bits / 8 bits/byte = 128 bytes.

    Therefore, it'd take 128 bytes to represent 1024 pixels (one display
    line on the monitor.

2)  There are 800 lines on the monitor, so:

    800 lines * 128 bytes/line = 102,400 bytes

  Therefore, it'd take just over 100K to display a black and white 1024X800
screen. 

  This is the reason why the monitor is b/w.  If we wanted 32 colors on
a 1024X800 monitor, we'd need:

  102,400 bytes/bitplane * 5 bitplanes = 512,000

  Now THAT would use up all your chip ram.


                 "Masquerading as a Man with a Reason,
                  My Charade is the Event of the Season..."
 
                           Wayward Son,
        
                              Kansas
        
-- 
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~ David Geary, Boeing Aerospace,               ~ 
~ Seattle - "THE DRIZZLE CAPITAL OF THE WORLD" ~
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