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badsect(8) [bsd man page]

BADSECT(8)						      System Manager's Manual							BADSECT(8)

NAME
badsect - create files to contain bad sectors SYNOPSIS
/sbin/badsect sector ... DESCRIPTION
Badsect makes a file to contain a bad sector. Normally, bad sectors are made inaccessible by the standard formatter, which provides a for- warding table for bad sectors to the driver; see bad144(8) for details. If a driver supports the bad blocking standard it is much prefer- able to use that method to isolate bad blocks, since the bad block forwarding makes the pack appear perfect, and such packs can then be copied with dd(1). The technique used by this program is also less general than bad block forwarding, as badsect can't make amends for bad blocks in the i-list of file systems or in swap areas. Adding a sector which is suddenly bad to the bad sector table currently requires the running of the standard DEC formatter, as UNIX does not supply formatters. Thus to deal with a newly bad block or on disks where the drivers do not support the bad-blocking standard badsect may be used to good effect. Badsect is used on a quiet file system in the following way: First mount the file system, and change to its root directory. Make a direc- tory BAD there and change into it. Run badsect giving as argument all the bad sectors you wish to add. (The sector numbers should be given as physical disk sectors relative to the beginning of the file system, exactly as the system reports the sector numbers in its con- sole error messages.) Then change back to the root directory, unmount the file system and run fsck(8) on the file system. The bad sectors should show up in two files or in the bad sector files and the free list. Have fsck remove files containing the offending bad sectors, but do not have it remove the BAD/nnnnn files. This will leave the bad sectors in only the BAD files. Badsect works by giving the specified sector numbers in a mknod(2) system call (after taking into account the filesystem's block size), creating a regular file whose first block address is the block containing bad sector and whose name is the bad sector number. The file has 0 length, but the check programs will still consider it to contain the block containing the sector. This has the pleasant effect that the sector is completely inaccessible to the containing file system since it is not available by accessing the file. SEE ALSO
mknod(2), bad144(8), fsck(8) BUGS
If both sectors which comprise a (1024 byte) disk block are bad, you should specify only one of them to badsect, as the blocks in the bad sector files actually cover both (bad) disk sectors. On the PDP-11, only sector number less than 131072 may be specified on 1024-byte block filesystems, 65536 on 512-byte block filesystems. This is because only a short int is passed to the system from mknod. 3rd Berkeley Distribution BADSECT(8)

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DISKPART(8)						      System Manager's Manual						       DISKPART(8)

NAME
diskpart - calculate default disk partition sizes SYNOPSIS
/usr/sbin/diskpart [ -p ] [ -d ] disk-type DESCRIPTION
Diskpart is used to calculate the disk partition sizes based on the default rules used at Berkeley. If the -p option is supplied, tables suitable for inclusion in a device driver are produced. If the -d option is supplied, an entry suitable for inclusion in the disk descrip- tion file /etc/disktab is generated; c.f. disktab(5). On disks that use bad144-style bad-sector forwarding, space is left in the last partition on the disk for a bad sector forwarding table. The space reserved is one track for the replicated copies of the table and suffi- cient tracks to hold a pool of 126 sectors to which bad sectors are mapped. For more information, see bad144(8). The disk partition sizes are based on the total amount of space on the disk as given in the table below (all values are supplied in units of 512 byte sectors). The `c' partition is, by convention, used to access the entire physical disk. The device driver tables include the space reserved for the bad sector forwarding table in the `c' partition; those used in the disktab and default formats exclude reserved tracks. In normal operation, either the `g' partition is used, or the `d', `e', and `f' partitions are used. The `g' and `f' partitions are variable-sized, occupying whatever space remains after allocation of the fixed sized partitions. If the disk is smaller than 20 Megabytes, then diskpart aborts with the message ``disk too small, calculate by hand''. Partition 20-60 MB 61-205 MB 206-355 MB 356+ MB a 15884 15884 15884 15884 b 10032 33440 33440 66880 d 15884 15884 15884 15884 e unused 55936 55936 307200 h unused unused 291346 291346 If an unknown disk type is specified, diskpart will prompt for the required disk geometry information. SEE ALSO
disktab(5), bad144(8) BUGS
Certain default partition sizes are based on historical artifacts (e.g. RP06), and may result in unsatisfactory layouts. When using the -d flag, alternate disk names are not included in the output. 4th Berkeley Distribution November 17, 1996 DISKPART(8)

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