Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!haven!umd5!jonnyg
From: jonnyg@umd5.umd.edu (Jon Greenblatt)
Newsgroups: comp.windows.x
Subject: Re: Contents of windows
Message-ID: <4841@umd5.umd.edu>
Date: 4 May 89 22:58:37 GMT
References: <4037@ficc.uu.net> <1306@esunix.UUCP>
Reply-To: jonnyg@umd5.umd.edu (Jon Greenblatt)
Organization: University of Maryland, College Park
Lines: 22

In article <1306@esunix.UUCP> bpendlet@esunix.UUCP (Bob Pendleton) writes:
rom article <4037@ficc.uu.net), by peter@ficc.uu.net (Peter da Silva):
)
))And given that 386 UNIX machines with enough RAM to run X typically burn a Meg
))for disk buffers, complaining about a bit of backing store doesn't really make
))a whole lot of sense.
)
)A bit of backing store? Lets see, my default xterm window size is
)80x60 using an 8x13 font so that is 499200 pixels. On a machine with
)32 bits/pixel (yes, such machines exist and run X) thats 1,996,800
)bytes or 1.95 megabytes.

	I do not know how xterm is handled but when you specify backing
store, you also specify the number of planes to back. Given that xterm
is monocrome, it uses 1 color plane. So a 80x60 xterm using an 8x13 font
that is 499200 pixels and at 1 bit per pixel thats 62400 bytes.

	Applications should not depend on backing store, it should
just enhance applications optionaly. Many machines will run out of memory if
even a small set of apps need backing store.

						JonnyG.