Invokes the Bad Block Locator utility (BAD), which analyzes
block-addressable devices and records the location of blocks that
cannot reliably store data. The /MEDIA qualifier is required. For
a complete description of BAD, including information about the
ANALYZE/MEDIA command and its qualifiers, see the OpenVMS Bad Block
Locator Utility Manual. This manual is posted with other archived
manuals on the OpenVMS Documentation website.
Format
ANALYZE/MEDIA device
device
Specifies the device that BAD will analyze. The device has the form:
ddcu: or logical-name
1 – Qualifiers
1.1 /BAD_BLOCKS
/BAD_BLOCKS[=LIST]
Adds the specified bad blocks to the detected bad block file
(DBBF). If the /BAD_BLOCK qualifier is specified along with the
/EXERCISE qualifier, the medium is tested once the bad blocks are
added to the DBBF.
If you do not specify a value for the /BAD_BLOCK qualifier, you are
prompted as follows:
BAD_BLOCKS =
In prompt mode, BAD reports any duplicate bad blocks.
Qualifier Value
List
Specifies the bad block locations to be added to the DBBF. Valid
codes for specifying bad block locations are:
Code Meaning
LBN Specifies the logical block number (LBN)
of a single bad block.
LBN:count Specifies a range of contiguous bad blocks
starting at the logical block number (LBN)
and continuing for "count" blocks.
SEC.TRK.CYL Specifies the physical disk address (sector,
track, and cylinder) of a single bad
sector. This code is valid only for last
track devices.
SEC.TRK.CYL:count Specifies a range of bad sectors starting
at the specified physical disk address
(sector, track, and cylinder) and
continuing for "count" sectors. This code
is valid only for last track devices.
You can specify these formats in any
integer combination or radix combination.
Note
The term "block" denotes a standard unit of 512
bytes, whereas the term "sector" denotes the
physical size of the device sector, which is not
always the same for all devices. For example, an
RL02 has a sector size of 256 bytes, while an RK07
has a standard sector size of 512 bytes.
1.2 /EXERCISE
/EXERCISE=(FULL,[NO]KEEP,PATTERN)
/NOEXERCISE (default)
Controls whether the media should actually be tested. You can
update the DBBF without erasing the contents of the volume by
using the /NOEXERCISE qualifier along with the /BAD_BLOCKS
qualifier.
Qualifier Keywords
FULL
Causes BAD to test the media using three test patterns (0s,
1s, and "worst case") instead of the default single "worst
case" pattern. The FULL keyword can be used only with
/EXERCISE. Note that the "worst case" test pattern always
remains on media tested with the /EXERCISE qualifier.
KEEP
Ensures the preservation of the current software detected bad
block file (SDBBF). The keep keyword is the default when
/NOEXERCISE is specified.
NOKEEP
Causes BAD to create a new SDBBF. The NOKEEP keyword is the
default when /EXERCISE is specified. This keyword cannot be
used with the /NOEXERCISE qualifier.
PATTERN=(value[,...])
Allows users to specify the value of a test pattern to be
used as "worst case". Up to an octaword of test pattern
data may be specified in decimal (%D), hexadecimal (%X),
or octal (%O) radixes. The default radix is decimal.
The pattern is specified in longwords. If two or more
longwords are specified, they must be enclosed in
parentheses and separated by commas.
1.3 /LOG
/LOG /NOLOG (default) Specifies whether a message is sent to the current SYS$OUTPUT device and SYS$ERROR, indicating the total number of bad blocks detected by BAD.
1.4 /OUTPUT
/OUTPUT[=filespec]
Specifies whether the contents of the DBBF are written to the
specified file. If you omit the /OUTPUT qualifier, no output
is generated.
If you specify /OUTPUT but omit the filespec, the contents of
the DBBF are written to the current SYS$OUTPUT device.
When you specify /OUTPUT, the /SHOW=AFTER qualifier is implied.
Qualifier Value
filespec
Identifies the output file for storing the results of the
medium analysis. If you specify a file type and omit the
file name, the default file name ANALYZE is used. The default
file type is ANL. If you omit the filespec, the results are
output to the current SYS$OUTPUT device.
No wildcard characters are allowed in the file specification.
1.5 /RETRY
/RETRY /NORETRY (default) Enables the device driver to retry soft errors.
1.6 /SHOW
/SHOW[=(keyword[,...])]
Lists the contents of the DBBF before or after (or both) the
medium is exercised or modified.
Qualifier Keywords
[NO]BEFORE,[NO]AFTER
Specifies whether the contents of the DBBF are listed before or
after (or both) the medium is exercised. After is the default.
2 – Examples
In examples 1 and 2, the contents of the data region on the medium
are not altered or destroyed; in examples 3, 4, and 5, all the data
on the medium is destroyed.
1. $ ANALYZE/MEDIA/BAD_BLOCKS=(4.4.4:3) DBA1:
The /BAD_BLOCKS qualifier in this example specifies a range of 3
bad blocks beginning at the physical disk address sector 4, track
4, cylinder 4. This range is added to the DBBF.
2. $ ANALYZE/MEDIA/LOG DBB1:
DEVICE DBB1: CONTAINS A TOTAL OF 340670 BLOCKS; 11 DEFECTIVE
BLOCKS DETECTED.
The command in this example requests BAD to report the total
number of bad blocks recorded in DBBFs for the disk mounted on
DBB1:. The medium is not exercised or altered in any way.
3. $ ANALYZE/MEDIA/EXERCISE/BAD_BLOCKS=(2) DBB1:
The command in this example adds the bad block specification to
the DBBF and then tests the media. The bad block in this example
is located at logical block number (LBN) 2.
4. $ ANALYZE/MEDIA/EXERCISE=KEEP DBA1:
This command tests the media while preserving the current SDBBF.
5. $ ANALYZE/MEDIA/EXERCISE/RETRY DBB1:
The command in this example directs the device driver to retry soft
errors.