Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!decwrl!shelby!glacier!jbn From: jbn@glacier.STANFORD.EDU (John B. Nagle) Newsgroups: comp.sys.next Subject: Re: fixing bad superblocks Keywords: NeXT bad block optical disk Message-ID: <18177@glacier.STANFORD.EDU> Date: 15 Mar 89 16:17:11 GMT References: <1208@blake.acs.washington.edu-> <1740@mentor.cc.purdue.edu> Sender: John B. Nagle Reply-To: jbn@glacier.UUCP (John B. Nagle) Organization: Stanford University Lines: 24 In article <1740@mentor.cc.purdue.edu-> gerrit@nova.cc.purdue.edu (Gerrit) writes: ->I remember a comment about this at the 3rd NeXT developer's camp. When ->they were going through "basic training" on the machine (booting, mounting, ->shutting down, etc) they told people let the machine sit for 60 seconds at ->some point near the end of a shutdown. I believe it was either just before ->powering off the machine or just after typing halt (I'm one of those who ->never shuts down my workstation, so my memory of the timing is fuzzy). ->Maybe someone else who was there will find this a refresher and fill in ->the details I'm forgetting. -> ->Anyway, the problem was that some quirk of Mach which prevents data from ->getting actually flushed to disk until some long timeout (something less ->than 60 seconds) had passed. The moral: warn people not to power off ->their machine without a 60 second pause *somewhere* near the end. This on a machine with a software-controlled power switch. Jobs has gone from the "appliance" concept to the other extreme, a cult object with obscure rituals which must be carried out correctly. One is reminded of Arthur C. Clarke's remark that "any sufficiently advanced technology is indistinguishable from magic," but I don't think that this is quite what Clarke had in mind. John Nagle