Date: Tue, 21 Apr 1998 10:51:36 +0200 (SAT) From: Robert Nordier <rnordier@iafrica.com> To: julian@whistle.com (Julian Elischer) Cc: current@FreeBSD.ORG Subject: Re: next stages in devfs Message-ID: <199804210851.KAA12020@ceia.nordier.com> In-Reply-To: <Pine.BSF.3.95.980420235954.20470C-100000@current1.whistle.com> from Julian Elischer at "Apr 21, 98 00:24:00 am"
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Julian Elischer wrote: > THere are a few stages that need to be taken for devfs at this point. > Some of them need discussion: > > removable media: > how do we detect that they have changed? > this is ok for SCSI, as the first access after a change will > have the usual effect.. (annoying but safe). > but there is no way to know that the floppy has changed (is there?, > I heard recently that there is actually a way to tell this under AT or > newer machines (that's everything with a 386 or greater). > does anyone have any info on this? Disk change line (line 34 of the interface cable) support was added when the AT was introduced. This is accessible via the digital input register (DIR) at port address 0x3f7. The MS default block device also implemented a virtual change line capability by storing system clock ticks at each access. In response to a "media check" request from the kernel, if <= two seconds had elapsed, the media was assumed to be unchanged. > [ ... ] > * There needs to be a handler for extended DOS partitions. > I need a tester for that too.. :-) I can help with that one. -- Robert Nordier To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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