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.