fdisk und bsdlabel Verwirrung

From: Manfred Lotz <manfred.lotz(at)yahoo.de>
Date: Wed, 31 Dec 2008 10:41:36 +0100

Hi Leute,
Habe eine 250GB Platte mit USB angehängt.

Ich definiere eine Slice über die ganze Platte mit dem sysinstall FDISK
partition editor.

Danach sagt fdisk:

******* Working on device /dev/da0 *******
parameters extracted from in-core disklabel are:
cylinders=30401 heads=255 sectors/track=63 (16065 blks/cyl)

Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=30401 heads=255 sectors/track=63 (16065 blks/cyl)

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
     start 63, size 488392002 (238472 Meg), flag 80 (active)
         beg: cyl 0/ head 1/ sector 1;
         end: cyl 1023/ head 254/ sector 63
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>

bsdlabel -e zeigt:

# /dev/da0s1:
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
   a: 488397152 16 unused 0 0
   c: 488392002 63 unused 0 0 # "raw" part,
don't edit

und wenn ich bsdlabel beende, kommt:

# bsdlabel -e /dev/da0s1
partition a: partition extends past end of unit
partition c: partition extends past end of unit
bsdlabel: partition c doesn't start at 0!
bsdlabel: An incorrect partition c may cause problems for standard
system utilities
re-edit the label? [y]:

Definiere ich die Slice neu mit:
fdisk -u /dev/da0

unter Bestätigung aller Default Werte, so kommt beim beenden von fdisk:

....
Should we write new partition table? [n] y
fdisk: Class not found

fdisk zeigt nun:

# fdisk /dev/da0
******* Working on device /dev/da0 *******
parameters extracted from in-core disklabel are:
cylinders=30401 heads=255 sectors/track=63 (16065 blks/cyl)

Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=30401 heads=255 sectors/track=63 (16065 blks/cyl)

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
     start 63, size 488392002 (238472 Meg), flag 80 (active)
         beg: cyl 0/ head 1/ sector 1;
         end: cyl 704/ head 254/ sector 63
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>

Der Unterschied ist nun end: cyl 704 statt 1023 wie oben.

Fragen:

a) Was wird über sysinstall anders gemacht? Unterschied: 704 zu 1023.
b) Was bedeutet fdisk: Class not found?
c) Wieso hat bsdlabel Anfangswerte, die über die Unit hinausgehen?
Wie setze ich (berechne ich) sinnvolle Werte für bsdlabel?

Hier fehlt mir total das Verstehen, was abgeht.

-- 
Manfred
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Received on Wed 31 Dec 2008 - 10:41:46 CET

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