Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!burl!hou3c!hocda!houxm!houxz!vax135!floyd!cmcl2!seismo!hao!hplabs!hpda!fortune!wdl1!jbn From: jbn@wdl1.UUCP (John B. Nagle) Newsgroups: net.unix-wizards Subject: Changing disks while the system is up Message-ID: <315@wdl1.UUCP> Date: Wed, 13-Jun-84 00:24:52 EDT Article-I.D.: wdl1.315 Posted: Wed Jun 13 00:24:52 1984 Date-Received: Fri, 15-Jun-84 00:13:55 EDT Lines: 14 First off, of course you don't do it while any file system on the volume is mounted. There is a bit defined in the hardware interface between the drive and controller for all SMD-type drives which is set whenever the pack is changed and remains set until cleared by the controller. The idea is that the software should thus be able to notice a pack change and take care of any housekeeping required. In RP06 and RM05 type removables, this bit just sets a bit in one of the device registers, which UNIX ignores. But the newer drives or drivers might do something with it. Another little-known feature of the SMD interface - you can stop the drive under program control. Generally not useful in the UNIX environment, though.