Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!cbosgd!mandrill!neoucom!wtm From: wtm@neoucom.UUCP Newsgroups: comp.sys.att Subject: Re: interleave/cluster size on 6300 w/ 3.2 Message-ID: <710@neoucom.UUCP> Date: Mon, 28-Sep-87 09:24:30 EDT Article-I.D.: neoucom.710 Posted: Mon Sep 28 09:24:30 1987 Date-Received: Thu, 1-Oct-87 00:55:45 EDT References: <2310@sphinx.uchicago.edu> Organization: Northeastern Ohio Universities College of Medicine Lines: 50 Summary: Experimentation required... There doesn't really seem to be a pat answer on what interleave factor is best. A lot depends on the applications programs as well as the underlying DOS. Sometimes a lousy interleave factor that results in poor general performance will speed up applications programs that do a lot of processing in between reading sectors from the disk. I know it is a pain, but trying several different interleave settings is worthwhile. In general, I've found that with the WX series (non RLL) controllers and Seagate 225s, an interleaf factor of 6 seems to work well with the 6300. You might try 5 or 7 as well. For RLL controllers, an interleaf factor of 3 or, perhaps, 4 seems to do pretty well. I noticed right away that DOS 3.2 seems slower than 3.1. Remember that the internal processing is greater for reading a given size file under 3.2. This is a consequence of the fact that cluster size is smaller. No matter waht you do, this'll get you. I don't mind slowing down a bit in return for the massive improvement in storage capacity. On my own 6300 at home, I had 5.5 meg free on a 30 meg drive with 3.1. After a backup and restore to the disk reformatted with 3.2, I had 11.3 meg free! Also, Lightning Disk Cache from Computer Support Group can make a big improvement is disk performance. We've tried one from Mace and Vcache from Golden Bow. Lightning provided the biggest benefit with the least memory requirement. By the way, Mace does market an interleave testing program, but we don't have it here yet. Also there is a P/D interleave tester available from one of the P/D distributors in Indiana (forget the name at the moment, and the catalog is at home). I think you can get information by calling 1-800-IBM-DISK. What does irk me is the $$##%@&! clock bug introduced into DOS 3.2. Each time the system is warmbooted, the dag-gone IBMDOS.COM gets the T.O.D. from the battery-backed clock. In the process, it sets the seconds register of the battery-backed clock to zero! On average, your battery clock is destined to loose 30 sec. each time you reboot.-- the amount lost obviously depends on when in a given minute you press the reset button (or CTL-ALT-DEL). When I get a chance, I'll see if I can find the offending code and develop a patch. This was *not* a bug under previous DOS versionns. Bill Bill Mayhew, Electrical Engineering Division of Basic Medical Sciences Northeastern Ohio Universities' College of Medicine Rootstown, OH 44272-9989 USA phone: 216-325-2511 (wtm@neoucom.UUCP ...!cbsogd!neocom!wtm)