Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!wuarchive!udel!haven!decuac!bacchus.pa.dec.com!shodha.enet.dec.com!elvira!ridder From: ridder@elvira.enet.dec.com (Hans Ridder) Newsgroups: comp.sys.amiga.tech Subject: Re: Finding disks Message-ID: <2008@shodha.enet.dec.com> Date: 19 Nov 90 18:49:51 GMT References: Sender: news@shodha.enet.dec.com Organization: Digital Equipment Corporation, Customer Support Center Lines: 38 In article chris@genly.UUCP (Chris Hind Genly) writes: >I posted a message a few days ago asking how to determine what disk >devices are on a system. This is the kind of problem you need to >solve if you're writing a file requester and want to put up buttons >with disk device names on them. >The info replacement walked through the dos device list looking for a >device with an associated task. >Once a device is found with a non-zero task entry, it can be tested to >see if it is really a disk device by trying to lock it. If you can >lock it, its a disk. I don't think it's a good idea to write code which depends on side effects like this. (Unless it's written down somewhere that only "disk devices" know how to Lock() -- I've never seen it.) As you pointed out, the Info replacment depended on the perceived effect that only devices have tasks, which later turned out to be wrong. There's always a danger in depending on undocumented side effects. IMHO, requesters should list *volumes*, not *devices*. Volume names are (or can be) much more descriptive to users than are names like "DH0" or "DF1". If device names are used, the user might have to click on every button to find a file, if the right disk is even in a drive. Devices (i.e. disk drives) don't have files on them, volumes do. Notice that the Workbench uses volume names, not devices names. It'll be much easier for the user to find the desired file if the names shown on the requester are consistent with the names he/she just saw on the Workbench screen. It's also much easier to find volumes in the device list. -hans ------------------------------------------------------------------------ Hans-Gabriel Ridder Digital Equipment Corporation ridder@elvira.enet.dec.com Customer Support Center ...decwrl!elvira.enet!ridder Colorado Springs, CO