From: utzoo!watmath!watcgl!dmmartindale
Newsgroups: net.unix-wizards
Title: Re: disk block interleave methods - (nf)
Article-I.D.: watcgl.188
Posted: Sun Feb 13 01:26:43 1983
Received: Mon Feb 14 00:49:22 1983
References: zehntel.740

I'm not aware of any of the disks that are used on UNIX systems which have
the packs formatted so that numerically adjacent sectors are not physically
adjacent on the pack - what you call "format interleaving" is not done.
There is sufficient gap between sectors that the controller can be ready
to read the next header by the time it comes by.  On a disk with N 
sectors per track, if you do an N-block read the whole thing is done with
one revolution of the pack;  interleaving the sectors at the pack level
would make several revolutions necessary, drastically slowing down the
transfer rate for long I/Os.