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From: rhealey@digir4.digibd.com (Rob Healey)
Newsgroups: comp.arch
Subject: Re: parity is for farmers?
Message-ID: <1991Jun05.205751.15327@digibd.com>
Date: 5 Jun 91 20:57:51 GMT
Article-I.D.: digibd.1991Jun05.205751.15327
Sender: @digibd.com
Organization: DigiBoard Incorporated, Eden Prairie, MN
Lines: 24

In article <1991Jun3.144909.24609@decvax.dec.com> kenton@abyss.zk3.dec.com (Jeff Kenton OSG/UEG) writes:
>|> >2) I don't know about the NeXT, but the Amiga used to also store checksums
>|> >   at the end of the file stored in RAM. Everytime in went to run
>the program
>|> >   it would calculate the checksum and compare it to the stored one,
>if they
>|> >   didn't match, it'd give you a dialog box saying so.
>
>The Amiga needed to do this because it supported multi-tasking without an MMU.
>Programs used to regularly trash each other's memory space.  It was one of the
>most painful development environments I ever worked with.  Neat graphics
>hardware, but pretty weak operating system.
>
	Then you must not have used any of the other nonprotected environments
	like DOS or Mac... Common problem for systems that try to do
	multiple things at once without MMU's. Add a few TSR's and a spooler
	together or the equiv for the Mac, then try to develop buggie code.
	You'd get the same result no matter what system you used. The
	problem is certainly not unique to the Amiga. Had the same problem
	on Apples II's and TRS-80's way back when. TRS-80's were real
	fun 'cause they ran tasks off a 60Hz timer inturrupt, code would
	overwrite the vector and kabooom! Fun stuff from the good 'ol days!

		-Rob