Date: Tue, 7 Nov 2000 10:10:05 -0800 (PST) From: "W.H.Scholten" <whs@xs4all.nl> To: freebsd-bugs@FreeBSD.org Subject: Re: misc/21675: Better and more disktab entries for MO drives Message-ID: <200011071810.KAA49546@freefall.freebsd.org>
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The following reply was made to PR misc/21675; it has been noted by GNATS. From: "W.H.Scholten" <whs@xs4all.nl> To: Bruce Evans <bde@zeta.org.au> Cc: freebsd-gnats-submit@FreeBSD.ORG Subject: Re: misc/21675: Better and more disktab entries for MO drives Date: Tue, 07 Nov 2000 15:57:45 +0000 Bruce Evans wrote: > > On Sun, 5 Nov 2000, W.H.Scholten wrote: > > > Correction for the disktab diff (se was 2048 for a 512 byte medium in > > the 230_max entry) and use of -m 0 in the newfs example. Plain diff (to > > the original disktab entry of e.g. fbsd 3.3R or 4.1R) attached. > > See a recent thread about fixing disklabel(8) (actually about making > disklabel(8) easier to use). There is no need for disktab entries > for drives that report their size to the driver, except possibly for > cloning a large number of identical drives with the same customized > label (the min* entries for floppies are a good example of this), but > customized labels belong in customized disktab files, not in the > standard one (the min* entries belong since they are used by the system > for building releases). Well, as I said in my first report, this stuff could be put in the fbsd documentation; there seems to be almost none. A problem is also bad disktab entries that appear in various places and, not willing to dive into the disklabel stuff, people (like me) try and they don't always work, least not in current releases where disklabel seems more picky and the error messages it spits out are unhelpfull to say the least (Weird: writing such a label to a brand new disk works, writing it to a disk that has been used before fails...). So, good examples are needed. Place it in disktab or the docs (see also below about the 230_max/640_max entries). > > +# ---- 90 mm magneto optical disk formats (dedicated disk): ---- > > +# Prepare a disk as follows (e.g. using device da0): > > +# disklabel -B -w -r da0 mo230 > > +# or: > > +# disklabel -w -r da0 mo640 > > +# (the -B flag currrently doesn't work for 640 MB media). > > The problem seems to be in disklabel(8). > > > +# and then: > > +# newfs -t 0 -u 0 -m 0 da0a > > +# (t=0 and u=0 means the values from disklabel will be used for # tracks and > > +# # sectors). > > Are t and u worth forcing to the physical values for mo disks? Are the > physical values actually physical? I force t and u for floppies, but the It makes a difference. If I don't use -t/-u then not all of the disk is used with the 230_max/640_max disklabel entries. It's nothing to do with physical formats, just using all available space on a disk (that's what the 230_max/640_max entries are for, as the CHS format specified by the drive does not use all available space). Wouter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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