mediainit - initialize disk or partition DDS tape
mediainit [-vr] [-f fmt_optn] [-i interleave] [-p size] pathname
mediainit initializes mass storage media by formatting the media,
writing and reading test patterns to verify media integrity, then
sparing any defective blocks found. This process prepares the disk or
tape for error-free operation. Initialization destroys all existing
user data in the area being initialized.
mediainit can also used for partitioning DDS tape media. See the -p
option below for further details.
The following command options are recognized. They can be specified
in any order, but all must precede the pathname. Options without
parameters can be listed individually or grouped together. Options
with parameters must be listed individually, but white space between
the option and its parameter is discretionary.
-v Normally, mediainit provides only fatal error
messages which are directed to standard error.
The -v (verbose) option sends device-specific
information related to low-level operation of
mediainit to standard output (stdout). This
option is most useful to trained service personnel
because it usually requires detailed knowledge of
device operation before the information can be
-r (re-certify) This option forces a complete tape
certification whether or not the tape has been
certified previously. All record of any
previously spared blocks is discarded, so any bad
blocks will have to be rediscovered. This option
should be used only if:
+ It is suspected that numerous blocks on
the tape have been spared which should not
have been, or
+ It is necessary to destroy (overwrite) all
previous data on the tape.
-f fmt_optn The format option is a device-specific number in
the range 0 through 239. It is intended solely
for use with certain SS/80 devices that support
multiple media formats (independent from
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interleave factor). For example, certain
microfloppy drives support 256-, 512-, and 1024-
byte sectors. mediainit passes any supplied
format option directly through to the device. The
device then either accepts the format option if it
is supported, or rejects it if it is not
supported. Refer to device operating manuals for
additional information. The default format option
-i interleave The interleave factor, interleave, refers to the
relationship between sequential logical records
and sequential physical records. It defines the
number of physical records on the media that lie
between the beginning points of two consecutively
numbered logical records. The choice of
interleave factor can have a substantial impact on
-p size Partition DDS cartridge media into two logical
separate volumes: partition 0 and partition 1:
+ size specifies the minimum size of
partition 1 (in Mbytes). The maximum
allowed value is 1200.
+ Partition 0 is the remainder of the tape
(partition 0 physically follows partition
1 on the tape).
The actual size of partition 1 is somewhat larger
than the requested size to allow for tape media
errors during writing. Thus, a size of 400
formats the DDS tape into two partitions where
partition 1 holds at least 400 Megabytes of data,
and the remainder of the tape is used for
partition 0 (for a 1300 Mbyte DDS cartridge, this
means that partition 0 has a size somewhat less
than 900 Mbytes).
Note that it is unnecessary to format a DDS tape
before use unless the tape is being partitioned.
Unformatted DDS media does not require
initialization when used as a single partition
tape. Accessing partition 1 on a single-partition
tape produces an error. To change a two-partition
tape to single-partition, use mediainit with 0
specified as the size.
pathname pathname is the path name to the character (raw)
device special file associated with the device
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unit or volume that is to be initialized.
mediainit aborts if you lack either read or write
permission to the device special file, or if the
device is currently open for any other process.
This prevents accidental initialization of the
root device or any mounted volume. mediainit
locks the unit or volume being initialized so that
no other processes can access it.
Except for SCSI devices, pathname must be a device
special file whose minor number of the device
being initialized has the diagnostic bit set. For
device special files with the diagnostic bit set,
the section number is meaningless. The entire
device is accessed.
When a given unit contains multiple volumes as defined by the drive
controller, any available unit or volume associated with that
controller can be initialized, independent of other units and volumes
that share the same controller. Thus, you can initialize one unit or
volume to any format or interleave factor without affecting formats or
data on companion units or volumes. However, be aware that the entire
unit or volume (as defined by the drive controller) is initialized
without considering the possibility that it may be subdivided into
smaller structures by the the operating software. When such
structures exist, unexpected loss of data is possible.
mediainit dominates controller resources and limits access by
competing processes to other units or volumes sharing the same
controller. If other simultaneous processes need access to the same
controller, some access degradation can be expected until
initialization is complete; especially if you are initializing a tape
cartridge in a drive that shares the root disk controller.
In general, mediainit attempts to carefully check any -f (format
option) or -i (interleave options) supplied, and aborts if an option
is out of range or inappropriate for the media being initialized.
Specifying an interleave factor or format option value of 0 has the
same effect as not specifying the option at all.
For disks that support interleave factors, the acceptable range is
usually 1 (no interleave) through n-1, where n is the number of
sectors per track. Refer to the appropriate device operating manual
for recommended values.
If a disk being initialized requires an interleave factor but none is
specified, mediainit provides an appropriate, though not necessarily
When a given device supports format options, the allowable range of
interleave factors may be related to the specified format option. In
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such instances, mediainit cannot check the interleave factor if one is
Most types of mass storage media must be initialized before they can
be used. HP hard disks, flexible disks, and cartridge tapes require
some form of initialization, but 9-track tapes do not. Initialization
usually involves formatting the media, writing and reading test
patterns, then sparing any defective blocks. Depending upon the media
and device type, none, some, or all of the initialization process may
have been performed at the factory. mediainit completes whatever
steps are appropriate to prepare the media for error-free operation.
Most HP hard disks are formatted and exhaustively tested at the
factory by use of a process more thorough but also more time-consuming
than appropriate for mediainit. However, mediainit is still valuable
for ensuring the integrity of the media after factory shipment,
formatting with the correct interleave factor, and sparing any blocks
which may have become defective since original factory testing was
HP flexible disks are not usually formatted prior to shipment, so they
must undergo the entire initialization process before they can be
When a tape is certified, it is thoroughly tested and defective blocks
are spared. mediainit usually certifies a tape only if it has not
been certified previously. If the tape has been previously certified
and spared, mediainit usually reorganizes the tape's spare block
table, retaining any previous spares, and optimizing their assignment
for maximum performance under sequential access. Reorganizing the
spare block table takes only a few seconds, whereas complete
certification takes about a half-hour for 150-foot tapes, and over an
hour for 600-foot tapes.
Reorganization of a tape's spare block table technically renders any
existing data undefined, but the data is not usually destroyed by
overwriting. To ensure that old tape data is destroyed, which is
useful for security, complete tape re-certification can be forced with
the -r option.
Some applications may require that a file system be placed on the
media before use. mediainit does not create a file system; it only
prepares media for writing and reading. If such a file system is
required, other utilities such as newfs, lifinit, or mkfs must be
invoked after running mediainit (see newfs(1M), lifinit(1), and
mediainit returns one of the following values:
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0 Successful completion.
1 A device-related error occurred.
2 A syntax-related error was encountered.
Appropriate error messages are printed on standard error during
execution of mediainit.
For a device that contains multiple units on a single controller, each
unit can be initialized independently from any other unit. It should
be noted, however, that mediainit requires that there be no other
processes accessing the device before initialization begins,
regardless of which unit is being initialized. If there are accesses
currently in progress, mediainit aborts.
Aborting mediainit is likely to leave the medium in a corrupt state,
even if it was previously initialized. To recover, the initialization
must be restarted.
During the initialization process, open() rejects all other accesses
to the device being initialized, producing the error EACCES (see
Partitioning of DDS tape media (-p option) is not supported.
mediainit was developed by HP.
lifinit(1), mkfs(1M), newfs(1M).
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