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From: madd@bucsb.bu.edu.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: Why 4.77MHz on clones?
Message-ID: <713@bucsb.bu.edu.UUCP>
Date: Mon, 2-Feb-87 17:01:27 EST
Article-I.D.: bucsb.713
Posted: Mon Feb  2 17:01:27 1987
Date-Received: Wed, 4-Feb-87 04:17:15 EST
References: <1292@ho95e.ATT.COM>
Reply-To: madd@bucsb.bu.edu.UUCP (Jim "Jack" Frost)
Distribution: na
Organization: ODO (Organization for the Disorganization of Organization)
Lines: 23

In article <1292@ho95e.ATT.COM> wcs@ho95e.ATT.COM (#Bill.Stewart) writes:
>A lot of PC clones offer two speeds, 4.77 and 7.x or 8.0 MHz, and claim
>the 4.77 is for compatibility.  What is the compatibility problem?
>Add-on hardware?  Stupid copy-protection?  Do I need to care?

There are a lot of things that you might want 4.77 for.  What happens
if your favorit space game, which at 4.77 mhz is almost impossible,
suddenly has double the horsepower?  Makes life tough.  Also, some
cards can't handle the ~8 mhz modes (though this is very uncommon in
my experience).  Finally, many diskette drives/controllers have timing
problems with 8 mhz modes.  This is very apparent with the THE PC+
machine that a friend of mine has.  Works perfect except that it will
occasionally lock up from timing problems with the diskette drive (if
it's used) when running @ 8 mhz.

There may be some other reasons, but these are popular ones.

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