Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!zaphod.mps.ohio-state.edu!caen!shorty.engin.umich.edu!milamber From: milamber@caen.engin.umich.edu (Daryl Scott Cantrell) Newsgroups: comp.sys.amiga.hardware Subject: Re: Hard disk speed: A3000 w/Q105 and Q170. Message-ID: <1990Dec4.061430.29257@engin.umich.edu> Date: 4 Dec 90 06:14:30 GMT References: <9012040118.AA116694@vttcf.cc.vt.edu> Sender: news@engin.umich.edu (CAEN Netnews) Organization: University of Michigan Engineering, Ann Arbor Lines: 33 In article <9012040118.AA116694@vttcf.cc.vt.edu> fmcphers@VTTCF.CC.VT.EDU (Frank McPherson) writes: [...] >used to dabble in the PC world, there was a nifty little parameter called >Interleave. I have a pretty non-technical idea of what this is, I.E. I know >the explanation of how the tracks are seperated on the disk, etc. Are there >any existing utilities on the Amiga for determining the optimum interleave >of a hard disk unit? [...] Interleave isn't quite the same under SCSI. With an ST-506 (the usual PC protocol) controller/drive, the controller works "closely" with the drive, telling it things like which track to seek to and which surface to read. On a SCSI system, the hard drive has an something called an imbedded host adap- tor. This is part of the actual cicuit board "on" the drive, and the theory is that the SCSI controller in your A3000 only sees the drive as a series of blocks numbered 0 to n. The circuitry on the drive is built with the opti- mum interleave and such in mind and does the appropriate translations. One side affect of this is that if you have a drive with, say, 2 surfaces, 10 cylinders, and 10 blocks per track, it doesn't matter if you lie to the controller and tell it that the drive has 1 track with 200 sectors on it or 20 surfaces with 5 cylinders of 2 sectors, as long as you get 200 blocks total. >-- Frank McPherson INTERNET: fmcphers@vttcf.cc.vt.edu -- -- +---------------------------------------+----------------------------+ | // Daryl S. Cantrell | These opinions are | | |\\\ milamber@caen.engin.umich.edu | shared by all of // | | |// Welcome to the Machine. | Humanity. \X/ | +---------------------------------------+----------------------------+