Article View: comp.sys.ibm.pc
Article #15433Re: Why 4.77MHz on clones?
From: muth
Date: Wed, 28 Jan 1987 18:27
Date: Wed, 28 Jan 1987 18:27
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1197 bytes
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?
Some software (mainly games) uses timing loops that are based on 4.77 MHz.
If you run these programs on machines with faster clocks (like a clone or
an AT) you end up with some real interesting results.
There may also be add-on hardware that counts on 4.77 MHz. I know of one
LAN adapter that works on AT's running at 6MHz, but not at 8MHz.
--
John A. Muth ...!{ihnp4,hplabs,sun,nsc}!amdahl!muth
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!watmath!clyde!rutgers!sri-unix!sri-spam!ames!amdahl!muth From: muth@amdahl.UUCP Newsgroups: comp.sys.ibm.pc Subject: Re: Why 4.77MHz on clones? Message-ID: <5426@amdahl.UUCP> Date: Wed, 28-Jan-87 13:27:47 EST Article-I.D.: amdahl.5426 Posted: Wed Jan 28 13:27:47 1987 Date-Received: Fri, 30-Jan-87 02:10:30 EST References: <1292@ho95e.ATT.COM> Distribution: na Organization: Amdahl Corp, Sunnyvale CA Lines: 13