Path: utzoo!attcan!uunet!cs.utexas.edu!husc6!ogccse!blake!uw-beaver!ubc-cs!van-bc! From: lphillips@lpami.wimsey.bc.ca (Larry Phillips) Newsgroups: comp.sys.amiga Subject: Re: How to measure disk speed Keywords: hard disk,Supra Message-ID: <712@lpami.wimsey.bc.ca> Date: 24 Aug 89 21:31:36 GMT Lines: 40 Return-Path: To: van-bc!rnews In <12218@orstcs.CS.ORST.EDU>, willieb@jacobs.cs.orst.edu (Willie Brown) writes: >As to MaxTransfer, yes you could bump it up to 128K or even 256K and get >some performance boost on the larger file transfers. Frankly, unless >you do extensive work with very large files or spend your days writing >benchmark programs, I doubt you'd ever notice the difference. As to >the low side, I've never seen anybody set MaxTransfer lower than 4K. >I just don't know what the file system would do with a drive that had >no MaxTransfer. There is no advantage to setting a value for MaxTransfer unless the driver you are using is incapable of handling large read or write requests. MaxTransfer tells the file system not to try requesting more than the number of bytes specified. Leaving out the MaxTransfer altogether lets the filesystem request any amount of data, which is the way the machine is supposed to work. The filesystem will request data in the largest amounts it can, which is determined by it knowing that the next data it needs is contained on a number of _consecutive_ blocks. As a general observation, anyone who uses any significant programs is, by definition, 'working with large files'. DPaint, AmigaBasic, and so on, are all fairly large files in themselves. If you let the filesystem do its thing, your performance will be maximized. So, as a company that produces hard drive subsystems, _PLEASE_ do not specify a MaxTransfer value unless your driver cannot handle large requests. -larry -- begin 777 .signature M268@>6]U(&1O;B=T('-E92!T:&ES('-E;G1E;F-E+"!Y;W4@6]U