Date: Mon, 9 Mar 1998 00:27:10 -0800 (PST) From: Doug White <dwhite@gdi.uoregon.edu> To: gkshenaut@ucdavis.edu Cc: questions@FreeBSD.ORG Subject: Re: using fdisk and disklabel to determine raw disk layout Message-ID: <Pine.BSF.3.96.980309002628.3844p-100000@gdi.uoregon.edu> In-Reply-To: <199803080007.QAA11292@myrtle1.bogs.org>
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On Sat, 7 Mar 1998, Greg Shenaut wrote: > I hate looking like an idiot, but I am now thoroughly confused. > The disklabel(8) program only deals with a single fdisk(8) partition, > so the offsets it reports are only relevant to its partition. Fdisk, > on the other hand, reports up to 4 fdisk partitions, but says nothing > about the contents of the partitions beyond its msdos code. > > If I understand this correctly, it would actually be possible for > there to be 4 independent disk labels on a raw disk, each with 8 > independent partitions; fdisk would report the layout of the 4 > labeled partitions, while you would need 4 runs of disklabel to > see all of the possible bsd partitions. Of course, there could be > non-bsd fdisk partitions which would not contain bsd labels; the > information reported by fdisk would probably suffice for them. Yuppers. > So, lamentably, I need to reiterate my original question, which > was how to construct automatically a complete map of the physical > layout of a disk drive, incorporating all sectors of the drive, > including those classified by fdisk, by disklabel, and by neither. > Also, I must ask whether it is possible to read and write the entire > physical drive using a single /dev name, such as /dev/rwd0--I ask > this because of the fact that the fdisk table doesn't start with > block 0 (hopefully, rwd0 bypasses all partitioning and just accesses > the physical drive). rwd0 is *the* disk. Period. I've never experimented with doing dd backups but I suppoz it's possible. I always use dump. ;-) Doug White | University of Oregon Internet: dwhite@resnet.uoregon.edu | Residence Networking Assistant http://gladstone.uoregon.edu/~dwhite | Computer Science Major To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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