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From: rick@pavlov.ssctr.bcm.tmc.edu (Richard H. Miller)
Newsgroups: comp.sys.mac.system
Subject: Re: 32 bit roms
Summary: hardware specifications
Message-ID: <5790@gazette.bcm.tmc.edu>
Date: 31 May 91 19:56:29 GMT
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	Unisys 2200/600ES machines have the capability to use two 16 megaword
	MSUs [32 megawords or 128 megabytes of memory] but the software cannot
	address more than 16 megawords of memory. (Sounds familer doesn't it).
	
	Until very recently all of the C-series Unisys machines have had the
	ability to use hardware gates for protection. This has been part of 
	the architecture since the 1100/90 which was introduced around 1985. 
	The ltest release of the operating system will finally take advantage
	of this feature.

	The DEC-10 systems had four machine states in which the processor
	could run. TOPS-10 only used two of them.

The point I am making here is that in many cases, the architectural definition
may allow capabilities which are beyond the scope of the software or the vendor
may choose to not take advantage of them. All I have seen in the material is
an indication that the hardware had this ability and I have never seen anything
which indicated that the software WOULD [as opposed to could] take advantage
of the features. 


-- 
Richard H. Miller                 Email: rick@bcm.tmc.edu
Asst. Dir. for Technical Support  Voice: (713)798-3532
Baylor College of Medicine        US Mail: One Baylor Plaza, 302H
                                           Houston, Texas 77030