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From: ching@amd.AMD.COM (Mike Ching)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Interleave factor on a 6300
Message-ID: <4319@amd.AMD.COM>
Date: Tue, 11-Aug-87 12:32:38 EDT
Article-I.D.: amd.4319
Posted: Tue Aug 11 12:32:38 1987
Date-Received: Thu, 13-Aug-87 04:42:30 EDT
References: <2928@mtgzz.UUCP> <1844@ttrdc.UUCP> <300@cpsc6b.cpsc6a.att.com>
Reply-To: ching@amd.UUCP (Mike Ching)
Organization: Advanced Micro Devices
Lines: 25

In article <300@cpsc6b.cpsc6a.att.com> crs@cpsc6b.cpsc6a.att.com (C. R. Seaman) writes:
>     The interleave values for a hard disk are based on the performance of
>the disk, not the system.  It basically determines the number of cylinders
>the head must pass after reading from/writing to a cylinder before it can
>read from/write to another cylinder.  If the drive takes 4 cylinders to
>reset, and you set the interleave to 3, the head will wait for almost a
>complete revolution before attempting another read/write.  Setting the value
>to 5 would mean that the drive is basically idle for one cylinder pass.
>

NO. The interleave for a hard disk is based on the performance of
the system and disk controller, not the disk. It is the number of
SECTORS the head passes while the system processes the data (either
creating another sector data buffer to write or moving the read
buffer to system memory). If the head passes the *next* sector
before the system is ready, it requires a whole revolution before
the sector passes under the head again.

Track-to-track interleave is the number of sectors that pass under
the head as the head moves from one cylinder to the next (so that
sector 0 is not adjacent to sector 0 of the next cylinder) and is
based on disk performance but is rarely what is being discussed when
interleave is the topic.

mike ching