Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!lll-lcc!ames!ucbcad!ucbvax!jade!eris!mwm From: mwm@eris.UUCP Newsgroups: comp.sys.amiga Subject: Re: Really bad disk (was Re: AMIGA questions.) Message-ID: <3009@jade.BERKELEY.EDU> Date: Thu, 2-Apr-87 12:55:54 EST Article-I.D.: jade.3009 Posted: Thu Apr 2 12:55:54 1987 Date-Received: Sun, 5-Apr-87 01:30:41 EST References: <2865@jade.BERKELEY.EDU> <1580@cbmvax.cbmvax.cbm.UUCP> <38@dalcsug.UUCP> <588@batcomputer.tn.cornell.edu> Sender: usenet@jade.BERKELEY.EDU Reply-To: mwm@eris.BERKELEY.EDU (Mike (My watch has windows) Meyer) Organization: Missionaria Phonibalonica Lines: 33 Keywords: disk trashed validate crash In article <588@batcomputer.tn.cornell.edu> engst@batcomputer.UUCP (Adam C. Engst) writes: >Horrors, does pulling a disk out of an Amiga while the drive is on really >kill it? I've never seen a computer that did that, of course with the >exception of a Mac, which won't even give the damn things back when you want This is the result of having a buffer cache. Computers with buffer caches tend to fry the disk if you don't give them time to flush the cache. Worst disk problems I've ever had resulted from pulling a disk from my z80 with cache, not hearing it beeping at me or noticing the message on the screen asking that I put the disk back, and putting in the next disk I wanted to work on. It promply flushed the cache (the full 1/2Meg) onto the new disk, resulting in two very dead disks. As for disks going bad, _every_ computer I've ever worked with has those problems, from Cray's to TRS-80's. Even the Apple ][. Buying high-dollar disks helps, but doesn't solve the problem. Apples ]['s seem to be better than average; but the error checking on the Woz machine is bad enought that hardware engineers claim that the silly thing will write to a pancake without complaining. N.B. - expensive systems have hooks to cover for bad blocks. Either the hardware will reserve tracks to map bad blocks to, or the software will arrange to not use those blocks. On the Cray, installing a new disk involves "flawing" the disk to find the bad blocks, then mapping file system partitions (not what you Unix wizards think they are!) around them.