EXCHANGE INITIALIZE — VMS 5.4
Formats and writes a label on a foreign mass storage volume. For
directory-structured devices, the device directory is also
initialized.
Format
EXCHANGE> INITIALIZE device-name
EXCHANGE> INITIALIZE /CREATE file-name
Prompts
For device or mounted virtual-device initialize:
Device: device-name
For new virtual-device creation (INITIALIZE/CREATE):
Filename: file-name
Additional information available:
ParametersDescriptionQualifiersExamples
Parameters
device-name
Specifies the name of the device on which the volume to be
initialized is physically mounted. The device must be mounted
/FOREIGN.
The device name can also refer to the name of a mounted
virtual-device which is to be re-initialized.
file-name
For INITIALIZE/CREATE, the file-name refers to the name of a file
which is to be created and initialized as a virtual device.
Description
The EXCHANGE INITIALIZE command is used to erase all files from a
volume. After initialization, the volume directory contains no
files. DOS-11 magnetic tapes and RT-11 block-addressable devices
may be initialized.
Qualifiers
Additional information available:
/ALLOCATION/BADBLOCKS/CREATE/DENSITY/EXTRA_WORDS
/MESSAGE/REPLACE/SEGMENTS/VOLUME_FORMAT
/ALLOCATION
/ALLOCATION=n
Specifies the allocation of a new virtual-device file as the
number of 512-byte blocks specified as n. If /ALLOCATION is not
specified when creating a new virtual-device file, EXCHANGE will
default to an allocation of 494 blocks, the size of a single
density floppy diskette. The maximum allocation is 65536 blocks.
A virtual-device file would normally be the size of a standard
device supported by both RT-11 and VMS. These sizes are:
Device Blocks
TU58 512
RX01 494
RX02 494 (single)
988 (double)
RL02 20480 (?)
RK06 27126 (?)
RK07 53790
The /ALLOCATION qualifier can also be used to reduce the size of
a physical device. For example, if one wanted to prepare an RL02
disk but only had an RK07 available, the RK07 could be
initialized to a volume of 20480 blocks. Later, when the RL02
was available, the files could be transferred to the RL02 without
any worry about whether or not they would fit on the smaller
device.
/BADBLOCKS
/BADBLOCKS[=RETAIN]
If /BADBLOCKS is specified, EXCHANGE will perform a bad-block
scan of the volume before initialization. This involves
writing a test pattern across the entire volume, and recording
which blocks generate errors. The volume is then initialized,
and a file with the name FILE.BAD is created on top of each of
the bad blocks, which prevents any other use of the bad areas.
If /BADBLOCKS=RETAIN is specified, EXCHANGE does not perform a
bad-block scan. Instead, it remembers the locations of all
*.BAD files on the volume. After initialization, a file named
FILE.BAD is created on top of each of the bad blocks.
/CREATE
Says that a virtual device should be created and initialized,
see help for Virtual_Device for more information on the use
of virtual devices.
/DENSITY
/DENSITY=density-value
Specifies for magnetic tape volumes, the density in bytes
per inch (bpi) at which the tape is to be written.
For tape volumes, the density value specified can be 800,
1600 or 6250, as long as the density is supported by the
tape drive. If you do not specify a density value for a
blank tape, the system uses a default density of the lowest
density supported by the tape drive.
For the RX02 dual-density diskette drive, use the DCL
command $ INITIALIZE /DENSITY=SINGLE or /DENSITY=DOUBLE to
reformat the diskettes to a different density. Then use the
EXCHANGE INITIALIZE command to create the RT-11 directory
structure.
NOTE
Floppy diskettes formatted in double density
cannot be read or written by the console block
storage device (an RX01 drive) of a VAX-11/780
until they have been reformatted in single
density.
/EXTRA_WORDS
/EXTRA_WORDS=n
Specifies, for RT-11 volumes, the number of extra words to add to
each directory entry, in addition to the required seven words.
This ability to increase the length of directory entries is
useful for some RT-11 applications. Increasing the size of the
directory entries reduces the number of entries that fit in each
directory segment.
Neither EXCHANGE nor the RT-11 operating system provides any
means of accessing the extra directory information directly.
/MESSAGE
/MESSAGE
/NOMESSAGE
The /MESSAGE qualifier controls whether or not EXCHANGE
prints a message which says that the volume was initialized.
The default is determined by the /MESSAGE qualifier on the
EXCHANGE verb when EXCHANGE was activated.
/REPLACE=RETAIN
/REPLACE=RETAIN
When /REPLACE=RETAIN is specified for an RT-11 volume, EXCHANGE
will retain the bad block replacement table and any *.BAD
files across initialization.
Note that the RETAIN option is required, EXCHANGE can not build
a replacement table for a volume. The RT-11 system builds and
uses the table based on specific hardware error conditions.
The VMS I/O system is different, and cannot be relied upon to
generate exactly the same error conditions. Therefore, it is
not possible for EXCHANGE to generate exactly the same replace-
ment table which would be generated by RT-11.
/SEGMENTS
/SEGMENTS=n
This qualifier defines, for RT-11 volumes, the number of 2-block
directory segments to allocate for the directory. The number of
segments in the directory establishes the number of files that
can be stored on a device. The system allows a maximum of 72
files per directory segment, and 31 directory segments per
device. The argument n represents the number of segments. The
valid range for n is from 1 to 31 (decimal). The default values
for n depend on the device type, as per the following table:
Device Segments
TU58 1
RX01 1
RX02 1 (single)
4 (double)
RL02 16
RK06 16
RK07 31
/VOLUME_FORMAT
/VOLUME_FORMAT=option
The /VOLUME_FORMAT qualifier defines the physical format of the
volume to be processed. The default format qualifier is
dependent on the device type. The default is /VOLUME_FORMAT=RT11
for block-addressable devices mounted foreign, and
/VOLUME_FORMAT=DOS11 for magnetic tape devices mounted foreign.
INITIALIZE is not valid for devices mounted native.
Option Function
RT11 Identifies an RT-11 formatted block-
addressable volume
DOS11 Identifies a DOS-11 formatted magnetic tape
volume
See section 6.0 for a complete description of the /VOLUME_FORMAT
qualifier and the defaults.
Examples
1. $ MOUNT/FOREIGN DLA2:
%MOUNT-I-MOUNTED, mounted on DLA2:
$ EXCHANGE
EXCHANGE> INITIALIZE DLA2:
%EXCHANGE-S-INITIALIZED, the RT-11 volume ATHENS$DLA2:
has been initialized
The above command initializes the volume mounted on the
RL02 drive ATHENS$DLA2: Since DLA2: is a block-
addressable device mounted foreign, /VOLUME=RT11 is
defaulted.
2. EXCHANGE> INITIALIZE MTA0:/DENSITY=1600
This command initializes the DOS-11 tape volume loaded
on MTA0:. The density was specified as 1600 bpi, since
the default would have been 800 bpi for an MT drive.