BADTRK(ADM) UNIX System V
Name
badtrk - scans fixed disk for flaws and creates bad track
table
Syntax
/etc/badtrk [ -e [ -m max ] ] [ -s qtdn ] [ -v ] [ -f device
]
Description
Used chiefly during system installation, badtrk scans the
media surface for flaws, creates a new bad track table,
prints the current table, and adds and deletes entries in
the table. Bad tracks listed in the table are ``aliased'' to
good tracks, such that when a process tries to read or write
a track listed in the bad track table, one of a replacement
tracks is used instead. These replacement tracks are
allocated when badtrk is run during installation. Changing
the number of replacement tracks allocated may require re-
installation of the operating system, so the number of
replacement tracks allocated should be fairly large.
To use badtrk, you must be in single user mode. (See
shutdown(ADM)).
Options
-f device
Opens the partition device and reads the bad track
table associated with that partition. device must be
the active UNIX partition of a fixed disk: /dev/rhd0a
for the first drive, /dev/rhd1a for the second, and so
on. The default is /dev/rhd0a.
-e Used by the installation procedure, the -e flag causes
badtrk to change the size of the bad track table.
WARNING: The -e flag should not be invoked by the user. Use
of the -e may restructure the hard disk, rendering much of
the information stored on it unusable.
-m max
Used only in non-interactive mode in conjunction with
-e, -m sets the maximum number of bad tracks to max.
-s arguments
Invokes badtrk non-interactively, causing it to scan
the disk for bad tracks and enter any errors found in
the bad track table. The arguments specify either
quick or thorough, and either destructive or non-
destructive scan:
[q]uick
[t]horough
[d]estructive
[n]on-destructive
The user should specify either q or t, and either d or n.
-v Used only in non-interactive mode in conjunction with
-e, -v displays progress messages indicating how much
of the disk has been scanned.
Usage
When badtrk is executed interactively, the program first
displays the main menu:
1. Print Current Bad Track Table
2. Scan Disk (You can choose Read-Only or Destructive later)
3. Add Entries to Current Bad Track Table by Cylinder/Head Number
4. Add Entries to Current Bad Track Table by Sector Number
5. Delete Entries Individually From Current Bad Track Table
6. Delete All Entries From Bad Track Table
Enter your choice or `q' to quit:
You are prompted for option numbers, and, depending upon the
option, more information may be queried for later.
A bad track table (option ``1'') might look like this:
Defective Tracks
_________________________________________
| Cylinder Head Sector Number(s)|
|________________________________________|
| 1. 190 3 12971-12987 |
|________________________________________|
Press <RETURN> to continue.
Option ``2'' scans the disk for flaws. If changes have been
made to your bad track table since you last updated the
table on disk (or since you entered badtrk), you will be
asked if you want to update the disk with the new table
before scanning. You should answer ``y'' to save your
changes, `n' if you don't want to save changes made up to
this point. Next you are prompted to specify the kind of
scan you wish to perform: either quick or thorough, and
either destructive or non-destructive. Choosing a
destructive scan will cause all data in the scanned region
to be lost. After you respond to these prompts, badtrk
begins its scan. You can interrupt a scan by typing ``q'' at
any time. You are then prompted to continue the scan or
return to the main menu.
As the program finds flawed tracks, it displays the location
of each bad track. An example error message might be:
wd: ERROR : on fixed disk ctlr=0 dev=0/47 block=31434 cmd=00000020
status=00005180, sector = 62899, cylinder/head = 483/4
(You may see this kind of message if there is a read or
write error during the scanning procedure.)
When the scan is complete, the main menu reappears. The
program automatically enters any detected flaws in the bad
track table.
If your disk is furnished with a flaw map, you should enter
these flaws into the bad track table. Select either option
``3'' or ``4'', depending upon the format of the flaw map
furnished with your disk. Enter the defective tracks, one
per line.
When you are satisfied that badtrk contains a table of the
desired flaws, quit the badtrk program by entering ``q'' at
the main menu.
If badtrk was invoked with the -e flag (which should only
occur when called by hdinit, during the installation
procedure), and the disk contains a valid division table,
the following message is displayed prior to the badtrk menu:
This device contains a valid division table. Additional
(non-root) filesystems can be preserved across this reinstallation.
If you wish to be able to preserve these file systems later, you must
not change the current limit of the bad track table, which is
n bad tracks. Do you wish to leave it unchanged? <y/n>:
If you respond ``y'', you will not be prompted later to
enter a new limit for the size of your bad track table. You
can add or delete entries, but you will not be allowed to
increase the maximum number of bad tracks allocated. If you
respond ``n'' and the size of your bad track table is
changed, your disk division table will be destroyed.
If you do not have a valid disk table or you selected ``n''
when prompted, you are prompted for the number of
replacement tracks to allocate. There will be a recommended
number of replacement tracks to allocate based on the number
of known bad tracks plus an allowance for tracks that may go
bad in the future. You should choose to allocate at least
the recommended number of replacement tracks. Make your
choice carefully, because if you want to change this amount
later, you will have to reinstall.
Before exiting, badtrk will ask whether you wish to update
the device with the new bad track table. If you wish to
save you changes, answer ``y''. If you wish to leave the
bad track table as it was before running badtrk, answer
``n''.
Notes
This utility can only be used in single-user mode.
If a bad spot develops in the boot blocks or system tables
at the very beginning of the fdisk partition, reinstallation
is required.
Files
/etc/badtrk
Value Added
badtrk is an extension of AT&T System V provided by the
Santa Cruz Operation.
(printed 2/15/90) BADTRK(ADM)