CYAMAMOTO%GUMBY@USC-ECLC.arpa (Cliff Yamamoto) (10/16/86)
I'm hoping some of the hard disk gurus out there could help me on this one I've been looking for a hard disk and a controller, comparing prices and such, when I came across a term I'm not familiar with. Can anyone explain to me what "Interleave" is? I ask this because I saw an advertisement for a controller claiming a 1:1 interleave. Is this good? Does this ratio affect the way the disk is formatted? Is there, or should there be some correlation or consideration with regard to the seek time of a selected hard drive? I'm sure Webster's definition is not applicable to hard drives and I was wondering how this affects the performance of a hard drive. Any information would be appreciated. Thanx in advance.. Cliff Yamamoto ARPA : CYAMAMOTO@GUMBY -------
jallen@netxcom.UUCP (John Allen) (10/23/86)
In article <4668@brl-smoke.ARPA> CYAMAMOTO%GUMBY@USC-ECLC.arpa (Cliff Yamamoto) writes: >Can anyone explain to me what "Interleave" is? I ask this because I saw >an advertisement for a controller claiming a 1:1 interleave. Is this good? >Does this ratio affect the way the disk is formatted? Is there, or should >there be some correlation or consideration with regard to the seek time of >a selected hard drive? >Cliff Yamamoto >ARPA : CYAMAMOTO@GUMBY Interleave refers to the physical placement of sectors in a track or cylinder. An interleave of "1" indicates adjacent placement. An interleave factor of "2" indicates logically sequential sectors are separated by one physical sector, "3" separated by 2 sectors, etc.. When a controller is specified to provide 1:1 interleave, this *should* mean that the device is capable of operating fast enough to read physically sequential sectors without allowing the media to rotate between each sector read (assuming that the request is for multiple sectors). If a drive is formatted at an interleave too low for the controller or system to handle, a full rotation will always occur between reads, lowering the transfer rate. Interleave has no effect on seek time; just on transfer rate. John Allen ========================================================================= NetExpress Communications, Inc. seismo!{sundc|hadron}!netxcom!jallen 1953 Gallows Road, Suite 300 (703) 749-2238 Vienna, Va., 22180 =========================================================================