franky@dutesta.UUCP (Frank W. ten Wolde) (11/29/88)
I would like to know your (NetLanders) opinion about the following:
I have a AT&T 3600 (actually Olivetti M24) computer and a Seagate
harddisk (ST251-1) using a Western Digital Controller (WD1002S-WX1).
For optimum results I must set the interleave factor to 5, which
slows down the data transfer rate (disk<-->host) to appr. 100K per
second.
Other people I have spoken to, have informed me that they run with
an interleave factor of 3 (data transfer: 170K/s), on a "simple" ;-)
IBM XT at 4.77MHz.
I would think that my Olivetti (clock 8MHz) should be able to at
least the same interleave(3)/transfer rate(170K/s), but for some
reason it will not work properly.
My questions are:
1. Is there someone out there who has the same problem?
2. Is there someone with an AT&T 3600 with a data rate
of 170K/s (and a corresponding interleave of 3)?
3. Is there someone who can tell me where the problem
originates and perhaps how to solve it?
Thanks in advance,
Frank ten Wolde
franky@dutesta
--
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Frank ten Wolde (PE1FCO) | UUCP: ..!mcvax!dutrun!dutesta!franky
Delft University of Technology |
Faculty of Electrical Engineering |
Section Computer Architecture |
Delft |
The Netherlands |
##########################################################################jvte@euraiv1.UUCP (Jan van 't Ent) (12/01/88)
franky@dutesta.UUCP (Frank W. ten Wolde) writes: >I have a AT&T 3600 (actually Olivetti M24) computer and a Seagate >harddisk (ST251-1) using a Western Digital Controller (WD1002S-WX1). >For optimum results I must set the interleave factor to 5, which >slows down the data transfer rate (disk<-->host) to appr. 100K per >second. We have had different results with different drives and controllers, most of the time the M24 works fine with interleave 4 (where i/l 3 results in 17 revolutions to read a single track), but sometimes we have to use interleave 7 (resulting in 5 revolutions to read a track, when i/l 3, 4, 5 or 6 doesn't do any good for that specific machine). <Jan> (Erasmus Universiteit Rotterdam, ApparatuurBeheer Fac.Econ.Wet.)
shurr@cbnews.ATT.COM (Larry A. Shurr) (12/03/88)
In article <1228@dutesta.UUCP> franky@dutesta.UUCP (Frank W. ten Wolde) writes: [Has AT&T "3600" (think you mean 6300) with ST251-1 and WD1002S-WX1.] [Use interleave of 5 and gets transfer rate of ~100KB/sec. True IBM PC'] [use interleave of 3 and get ~170KB/sec. The PC runs at 4.77MHz and the] [Olivetti (what he actually has and which is the same thing as an AT&T] [6300) runs at 8MHz.] >My questions are: > 1. Is there someone out there who has the same problem? > 2. Is there someone with an AT&T 3600 with a data rate > of 170K/s (and a corresponding interleave of 3)? > 3. Is there someone who can tell me where the problem > originates and perhaps how to solve it? Frank, You've been had. The Olivetti M24/AT&T 6300 has an 8086 CPU running at 8MHz, but I understand that the bus runs at 4MHz (half the system clock rate) and *NOT* 4.77MHz. Consequently, your raw data transfer rate is actually LESS than a real-but-slower IBM PC. Here at the Labs, 6300's seem to perform well with an interleave of 4 in configurations similar to yours, but interleave factor 3 is a dog. Thus, there a lot of "slow" 6300's around because their hard disks came preformatted with an interleave factor of 3 and their owners don't know enough to realize what is wrong. regards, Larry -- Signed: Larry A. Shurr (att!cbnews!shurr or osu-cis!apr!las) Clever signature, Wonderful wit, Outdo the others, Be a big hit! - Burma Shave (With apologies to the real thing. Above represents my views only.)