Date: Wed, 21 Jan 2004 04:05:30 -0800 (PST) From: Dan Strick <strick@covad.net> To: fbsd_user@a1poweruser.com Cc: dan@mist.nodomain Subject: Re: using cd rw drive Message-ID: <200401211205.i0LC5Udo000731@mist.nodomain>
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There is a third reason why you can't treat a CD-RW just like a hard disk drive: 3) A CD has 2048 byte data sectors. FreeBSD hard disk drivers expect 512 byte sectors. The CD driver might have to be modified to fake the hard disk sector size. Even if the UFS fragment size is a multiple of 2048 bytes the OS might attempt 512 byte transfers to access disk labels. I am not sure the CD driver will look for disk labels or support all the special ioctls used by the disklabel program. Since the CD driver fakes a trivial partition table, you should not have to use the disklabel program anyway. If the newfs program and the OS do not do gratuitous sub-fragment transfers, setting the fragment size to 2048 bytes might finesse the sector size problem. Even if it works, UFS is probably not normally the best file system for CD-RW. The long seek times discourage random access and favor contiguous files. (However, I do see a small environmental niche for UFS on CD.) Given all these nagging little software issues, we may be stuck with mkisofs/burncd/cdrecord for the near future even with CD-RW. Dan Strick strick@covad.net
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