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From: grege@gold.gvg.tek.com (Gregory Ebert)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Parallel port data rates
Message-ID: <1872@gold.gvg.tek.com>
Date: 15 Jan 91 17:21:16 GMT
References: <91009.081227NIBMSCM@NDSUVM1.BITNET> <1865@gold.gvg.tek.com> <336@rc6.urc.tue.nl>
Organization: Grass Valley Group, Grass Valley, CA
Lines: 18

I (Greg Ebert) write:
-
-If you check BUSY, the maximum rate is 500Kbytes/sec.
-If you dont check busy (dumb, really dumb!), the rate is 667Kbytes/sec.
->>>Keep in mind these are absolute MAXIMUM numbers <<<
-Your actual mileage will vary due to overhead for refresh, interrupts, and
-processing.


In article <336@rc6.urc.tue.nl> rcstack@urc.tue.nl writes:
-If you don't have a clue about hardware please don't say these things,
-probably never heard of wait states! In typical AT clones 8 bit IO
-accesses have 4 wait states inserted. The 80286 isn't a RISC processor
-so instructions generally take longer than bus cycles.


As I stated, these are MAXIMUM rates, and I have obtained results very
close to these numbers with a 386-33 w/ cache and posted I/O writes.