Date: Sun, 30 Jun 1996 23:26:23 +1000 (EST) From: Gary Roberts <garyr@ajax.wcs.uq.edu.au> To: 100120.3121@CompuServe.COM (Berend de Boer) Cc: freebsd-stable@FreeBSD.ORG Subject: Re: Help with fdisk Message-ID: <199606301326.XAA06963@ajax.wcs.uq.edu.au> In-Reply-To: <960628200112_100120.3121_EHQ55-1@CompuServe.COM> from "Berend de Boer" at Jun 28, 96 04:01:12 pm
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Berend de Boer writes: > I have a harddisk with a loose partition at the end. I like to make this > available to FreeBSD, however I cannot get fdisk to work. Maybe someone can > help? I'm not sure if this is the right list to post, so if I'm wrong please > direct me to the correct one (but I couldn't find a more appropriate list). You probably would have been much better off sending this to -questions. My impression (and someone will undoubtedly correct me if I'm wrong ;->.) is that fdisk `wraps' the cylinder count after 1023 so that when you try to get `1024' it is reported by fdisk as `0'. This is quite off-putting but harmless since fdisk seems to do the right thing and you will get your new slice as you want. I say this from experience as I have sliced up a couple of large IDE disks this way with no problems. You should have proper backups of any critical data before you start this :->. There is, however, something funny with the numbers you produce below. > cylinders=1647 heads=16 sectors/track=63 (1008 blks/cyl) > The data for partition 0 is: > sysid 4,(Primary DOS with 16 bit FAT) > start 63, size 41265 (20 Meg), flag 0 > beg: cyl 0/ sector 1/ head 1; > end: cyl 40/ sector 63/ head 15 This looks fine - 41 cyls X 1008 blks/cyl = 41328 (ie. = 63 + 41265) > The data for partition 1 is: > sysid 165,(FreeBSD/NetBSD/386BSD) > start 41328, size 1023120 (499 Meg), flag 80 > beg: cyl 41/ sector 1/ head 0; > end: cyl 1023/ sector 63/ head 15 Now to me this is a puzzle. If the size is 1023120 (ie. 1008 X 1015) then the ending cylinder should be 1055 (41 + 1015 - 1) and not 1023. My recollection is that fdisk would `wrap' and report the ending cylinder as something like cyl 31 (1055 - 1024). It was a fair while ago that I did this so my memory may be faulty :->. > I like to turn the 2nd partion to the 306MB I should have availabe. Using a > calculator (..., anyone used NT's DiskManager?) I determined the startaddress > and size, however I coudn't get fdisk to let this partition start at cilinder > 1024, even when explicitly specifiying the beginaddress: > > ---------------------------fdisk start--------------------------------------- > The data for partition 2 is: > <UNUSED> > Do you want to change it? [n] y > Supply a decimal value for "sysid" [0] 165 > Supply a decimal value for "start" [0] 1032192 > Supply a decimal value for "size" [0] 627984 > Explicitly specifiy beg/end address ? [n] > sysid 165,(FreeBSD/NetBSD/386BSD) > start 1032192, size 627984 (306 Meg), flag 0 > beg: cyl 0/ sector 1/ head 0; > end: cyl 622/ sector 63/ head 15 > Are we happy with this entry? [n] > ---------------------------fdisk end---------------------------------------- As I said, I would have expected fdisk to have reported the end of slice (partition) 1 as being cyl 31 and not 1023 if the size was 1023120. I would expect the "start" of slice 2 to be 1064448 (41328 + 1023120) and not 1032192 as your example shows. I would also expect the "size" to be 595728 so that 1064448 + 595728 = 1660176 which is 1647 cyls. Perhaps you could recheck your numbers? From what you have supplied, the ending cyl of 1023 for slice 1 seems to be bogus to me. Maybe someone else may wish to comment. Cheers, -- Gary Roberts (garyr@wcs.uq.edu.au) (Ph +617 3844 0400 Fax +617 3844 0444) 4th Floor, South Bank House, 234 Grey St, South Bank QLD 4101 Australia.
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