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OpenVMS System Manager's Manual
9.3 Initializing Volumes
You initialize a disk or tape volume for one or both of the following
reasons:
- To delete all old information from the volume.
- To give the volume a structure that is recognized by the operating
system.
This structure prepares a volume to receive data and stores
it so that the operating system can locate it easily.
Before you or any user can write files or data to a disk or a tape
volume, you must initialize a volume.
Caution
Initializing a disk volume removes links to existing files on the
volume, which, in effect, deletes (but does not erase) the files. To
erase the data in a file, use the INITIALIZE/ERASE command.
Do not initialize a volume that contains data that users want to keep.
(Initializing a volume each time you use it is not necessary.)
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Steps for Setting Up Disk or Tape Volumes
To set up a disk or tape volume, you need to perform two steps. In each
step you enter a DCL command, as follows:
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1. INITIALIZE
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Formats the volume and writes an identifying label on it. This
effectively removes the previous contents of the volume. (Initializing
a volume each time you use it is not necessary.)
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2. MOUNT
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Provides the user's process with access to a volume's files or data.
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This section contains instructions for initializing volumes.
Section 9.5 contains instructions for mounting volumes. Before you
initialize a volume, you might want to refer to Section 9.4, which
contains information about volume protection.
Setting Up Media on a Workstation
For workstations with removable media, users can
perform the tasks shown in Table 9-7 unassisted.
Table 9-7 Tasks Users Can Perform Unassisted
| Task |
Description |
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Load
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Insert the media into the drive.
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Initialize
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Remove all previous contents from the media. (VOLPRO privilege is
required for most operations.)
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Mount
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Logically mount the media and allocate the device (requires SYSNAM,
GRPNAM, or VOLPRO privilege for various operations). To mount a volume
on a device, you must have read (R), write (W), or control (C) access
to that device.
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Perform file operations
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Access files and perform the desired operations on them.
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Dismount
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Logically dismount the media and deallocate the device (requires GRPNAM
and SYSNAM user privileges to dismount group and system volumes).
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Unload
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Remove the media from the drive compartment.
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For additional information about manipulating removable media on your
workstation, refer to the hardware manuals that accompany your
workstation.
On VAX systems, also refer to the upgrade and installation supplement
for your computer.
9.3.1 Using the INITIALIZE Command
Use the DCL command INITIALIZE to format and write a label to the
volume.
To initialize a disk or tape volume, enter the INITIALIZE command using
the following format:
INITIALIZE device-name[:] volume-label
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where:
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device-name
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Specifies the name of the device on which the volume is to be
physically mounted and then initialized. To prevent initializing
another user's volume, allocate a device before you initialize the
volume. (Prior allocation is not required, however.)
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volume-label
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Specifies the identification to be encoded on the volume. For a disk
volume, you can specify a maximum of 12 ANSI characters; for a magnetic
tape volume, you can specify a maxiumum of 6 alphanumeric characters.
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To initialize a public volume, you must specify the /SYSTEM qualifier
with the DCL command INITIALIZE:
INITIALIZE/SYSTEM device name[:] volume-label
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For more details on INITIALIZE command format, refer to the
OpenVMS DCL Dictionary.
Examples
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The command in this example initializes the disk volume DUA2: and
labels the volume TEMP.
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The command in this example initializes the tape volume on MUB2:
and labels the volume TEST.
The OpenVMS User's Manual contains additional examples of the INITIALIZE
command.
9.3.2 Using INITIALIZE Command Qualifiers
Table 9-8 describes a number of qualifiers you can use with the
INITIALIZE command. Selecting appropriate values for these qualifiers
and selecting the appropriate position for the index file involve
tradeoffs. The OpenVMS DCL Dictionary contains more information about each
qualifier.
Table 9-8 INITIALIZE Command Qualifiers
| Qualifier |
Description |
/CLUSTER_SIZE=
number-of-blocks
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Specifies minimum allocation unit in blocks.
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/HEADERS=
number-of-headers
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Specifies the number of file entries, called
file headers, that you expect to have in INDEXF.SYS,
the index file. It controls how much space is initially allocated to
INDEXF.SYS for headers. (The system accesses the index file each time
it locates a file on disk.)
Each file on a disk requires at least 1 file header and each header
occupies 1 block within INDEXF.SYS. Files that have many access control
entries (ACEs) or that are very fragmented might use more than 1
header. The default value of 16 leaves room for fewer than 10 files to
be created before INDEXF.SYS must extend. Therefore, estimate the total
number of files that will be created on the disk and specify it here. A
good estimate improves performance of disk access. Setting the number
too low can result in a fragmented index file. However, if you set the
number too high, space allocated to headers cannot be made available
later for file storage and can lead to wasted disk space. This value
cannot be changed without reinitializing the volume.
INDEXF.SYS is limited as to how many times it can extend. When the
map area in its header (where the retrieval pointers are stored)
becomes full, files cannot be created and the message
SYSTEM-W-HEADERFULL is displayed.
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/INDEX=
position
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Determines the location of the index file on a volume, using the
keyword BEGINNING, MIDDLE, END, or BLOCK:
n. The index file lists the names and addresses of all disk
files, so it is constantly referenced.
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/MAXIMUM_FILES=
n
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Specifies the maximum number of entries in the index file, and
therefore limits the number of files that a volume can contain. Once
set, the maximum number of files for a volume cannot be increased
without reinitializing the disk.
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/PROTECTION=
(ownership=[:access][,...])
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Specifies the protection code to be assigned to a volume. See
Section 9.4 for details.
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/WINDOWS=
n
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Sets the default number of mapping pointers to be allocated for file
windows. When a file is opened, the file system uses mapping pointers
to access data in the file. The file system can read one file segment
into memory for each available pointer.
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Caution
The default value for the /HEADER qualifier is generally insufficient
for ODS-2 disks. To improve performance and avoid SYSTEM-F-HEADERFULL
errors, Compaq strongly recommends that you set this value to be
approximately the number of files that you anticipate having on your
disk. However, grossly overestimating this value will result in wasted
disk space.
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Examples
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$ INITIALIZE/HEADERS=100000 DUA3:
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This example shows how many entries to allocate in the index files
for a large disk (a small disk might allocate 2000 entries).
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$ INITIALIZE/MAXIMUM_FILES=20000 DUA3:
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This example shows how to specify the characteristics of a small
disk. Note that each directory and each extension header of a
multiheader file counts as a file against this maximum value.
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$ INITIALIZE/WINDOWS=10 DUA3:
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This example shows how to cite a large number of pointers for a
large disk of 500 MB.
9.3.3 Initializing a New Volume with ODS-5 Format
You can initialize a new volume as an ODS-5 volume by entering the
INITIALIZE command using the following format. Note that once you
initialize the volume, the current contents of the volume are lost.
$ INITIALIZE /STRUCTURE_LEVEL=5 device-name volume-label
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For example:
$ INITIALIZE /STRUCTURE_LEVEL=5 DKA300: DISK1
$ MOUNT DKA300: DISK1 /SYSTEM
%MOUNT-I-MOUNTED, DISK1 mounted on _STAR$DKA300:
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The first command initializes the DKA300: device as an ODS-5 volume and
assigns the volume-label DISK1. The second command mounts the DISK1
volume as a public volume.
To verify that the volume has been initialized as an ODS-5 volume, you
can enter a SHOW DEVICE/FULL command; the system displays messages
similar to the following:
$ SHOW DEVICE DKA200:/FULL
Disk $10$DKA200:, device type RZ74, is online, allocated, deallocate
on dismount, mounted, file-oriented device, shareable.
Error count 0 Operations completed 155
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.
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Volume Status: ODS-5, subject to mount verification, file high-water
marking, write-back caching enabled.
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An alternative method for displaying the volume type is to issue a
command and receive a response similar to the following:
$ WRITE SYS$OUTPUT F$GETDVI ("DKA200:","ACPTYPE")
F11V2
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F11V2 indicates that the volume is ODS-2.
Note
If you plan to add the new volume to a volume set, the structure level
of the new volume must match that of the volume set. If it does not,
the Mount utility displays the following error message:
Structure level on device ... is inconsistent with volume set.
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9.3.4 Assisting Users in Accessing and Initializing Volumes
Initializing volumes for users might be necessary in some circumstances:
- If the volume previously contained data, the protection code might
prevent users from accessing and initializing the volume.
- If the first file section on the volume has not reached its
expiration date, users might not be able to initialize a tape volume.
- If the volume is owned by anyone except [0,0], the user must have
VOLPRO privilege to override volume protection. If users do not have
VOLPRO privilege, they must ask the previous owner of the volume or
you, as system manager, to initialize it for them.
- If a tape is blank, the user must have VOLPRO and OPER privileges
to access and initialize it.
9.4 Protecting Volumes
Protection based on user identification codes (UICs) restricts users'
access to volumes. By assigning access types to volumes, you determine
the kinds of actions various groups of users can perform on volumes.
Section 9.4.1 and Section 9.4.2 explain the differences between
UIC-based protection for disk and tape volumes.
For additional access control, you can set access control lists (ACLs)
on volumes. Volume ACLs are copied from the VOLUME.DEFAULT security
class template. See Section 12.6 for more information about ACLs.
Table 9-9 shows the types of access you can assign to disk and tape
volumes.
Table 9-9 Access Types for Disk and Tape Volumes
| Access Type |
Gives you the right to... |
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Read
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Examine file names, print, or copy files from the volume. System and
owner categories always have read access to tape volumes.
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Write
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Modify or write to existing files on a volume. The protection of a file
determines whether you can perform a particular operation on the file.
To be meaningful, write access requires read access. System and owner
categories always have write access to tape volumes.
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Create
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Create files on a disk volume and subsequently modify them. Create
access requires read and write access. This type of access is invalid
for tape volumes.
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Delete
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Delete files on a disk volume, provided you have proper access rights
at the directory and file level. Delete access requires read access.
This type of access is invalid for tape volumes.
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Control
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Change the protection and ownership characteristics of the volume.
Users with the VOLPRO privilege always have control access to a disk
volume, with the following exceptions:
- Mounting a file-structured volume as foreign requires control
access or VOLPRO privilege.
- Mounting a volume containing protected subsystems requires SECURITY
privilege.
Control access is not valid with tapes.
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For more information about specifying protection codes, refer to the
OpenVMS Guide to System Security. Chapter 12 discusses protection in general.
The following sections explain how to perform these operations:
9.4.1 Protecting Disk Volumes
For file-structured ODS-2 volumes, the OpenVMS operating system
supports the types of access shown in Table 9-9. The system
provides protection of ODS-2 disks at the volume, directory, and file
levels. Although you might have access to the directories and files on
the volume, without the proper volume access, you are unable to access
any part of a volume.
The default access types for the disk volume owner [0,0] are:
S:RWCD, O:RWCD, G:RWCD, W:RWCD.
The system establishes this protection with the default qualifier of
the INITIALIZE command (/SHARE). Any attributes that you do not specify
are taken from the current default protection.
Ways to Specify Protection
You can change permanently stored protection information in the
following ways:
- Use ACLs. The entire security profile (owner UIC, protection code,
and ACL) is stored on the volume. If you change the volume security
profile for a volume mounted clusterwide, the change is distributed to
all nodes in the cluster. If you dismount and remount a volume, the
security profile for the volume is preserved.
- Use the DCL command SET SECURITY to modify the default security
profile after a volume is mounted, including UIC- and ACL-based
protection.
- Use protection qualifiers with the DCL command INITIALIZE to
specify UIC-based protection when you initialize a volume.
You can
also specify protection when you mount disk volumes, but you ordinarily
do not do so because the protection that you specify is in effect only
while the volume is mounted. For details, refer to the Mount utility
(MOUNT) in the OpenVMS System Management Utilities Reference Manual.
- Use the DCL command SET VOLUME after you mount a volume to change
UIC-based volume protection.
The following sections explain how to perform these tasks:
9.4.1.1 Specifying Protection When You Initialize Disk Volumes
This section explains how to specify UIC-based volume protection and
ISO 9660-formatted media protection when you initialize volumes.
Specifying UIC-Based Protection
You can specify protection in one of the following ways when you
initialize volumes:
- Use the /PROTECTION qualifier with the INITIALIZE command. For
example:
$ INITIALIZE DUA7: ACCOUNT1/PROTECTION=(S:RWCD,O:RWCD,G:R,W:R)
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This example specifies a protection code for the disk volume
ACCOUNT1 on the DUA7: device. The UIC of the volume is set to your
process UIC.
- Use one or more of the qualifiers shown in Table 9-10 with the
INITIALIZE command. However, the protection that you set using the
/PROTECTION qualifier overrides any of the defaults set when you use
any other qualifier.
Using INITIALIZE Command Qualifiers for Protection
You usually do not change volume protection after you initialize a
volume. By specifying a protection qualifier with the INITIALIZE
command, you can establish the default protection of a volume. (The
default qualifier of the INITIALIZE command is /SHARE, which grants all
types of ownership all types of access.)
Table 9-10 explains the
qualifiers you can use to specify disk volume protection when you
initialize disk volumes.
Table 9-10 INITIALIZE Command Qualifiers for Protection
| Qualifier |
Explanation |
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/PROTECTION
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The protection you specify with this qualifier overrides any protection
you specify with other qualifiers.
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/SYSTEM
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All processes have read, write, create, and delete access to the
volume, but only system processes can create first-level directories.
([1,1] owns the volume.) See the note following this table.
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/GROUP
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System, owner, and group processes have read, write, create, and delete
access to the volume. World users have no access.
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/NOSHARE
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System and owner processes have read, write, and delete access to the
volume. World users have no access. Group users also have no access
unless you specify the /GROUP qualifier.
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Note
The /SYSTEM qualifier grants all users complete access. However, users
cannot create directories or files unless you perform one of the
following actions:
- Change the protection on the newly created master file directory
(MFD), [000000]000000.DIR;1 to allow users to create their own
directories under this parent directory.
- Under the master file directory, create user directories that give
users write access so that they, in turn, can create their own
directories.
System managers usually choose the second method.
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Table 9-11 shows the UIC and protection that the system sets for
disk volumes when you use the default, /SHARE, and other qualifiers
with the INITIALIZE command.
Table 9-11 Protection Granted with INITIALIZE Command Qualifiers
| Qualifier |
UIC |
Protection |
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/SYSTEM
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[1,1]
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S:RWCD,O:RWCD,G:RWCD,W:RWCD
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/SYSTEM/NOSHARE
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[1,1]
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S:RWCD,O:RWCD,G:RWCD,W:RWCD
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/GROUP
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[x,0]
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S:RWCD,O:RWCD,G:RWCD,W
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/SHARE (the default)
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[x,x]
1
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S:RWCD,O:RWCD,G:RWCD,W:RWCD
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/NOSHARE
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[x,x]
1
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S:RWCD,O:RWCD,G,W
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1x,x is the UIC of the process that performs the
initialization.
Specifying ISO 9660-Formatted Media Protection
The OpenVMS implementation of ISO 9660 does not include volume or
volume set protection. The protection specified for the device on which
the media is mounted determines accessibility to the ISO 9660 volumes
or volume sets.
By default, the device protection is assigned to ISO 9660 files and
directories. When you mount the volume, you can specify additional file
protection using the UIC and PERMISSION protection fields included in
the Extended Attribute Records (XARs) that might be associated with
each file.
You can enable the protection fields by specifying either of the
following items:
- XAR mount option, using the following format:
When you specify the XAR option for a file that has an associated
XAR, the protection fields in the XAR are enabled.
- DIGITAL System Identifier (DSI) mount option, using the following
format:
If you specify the DSI option, you enable the XAR permissions Owner
and Group for XARs containing DSI.
For more information about the XAR and DSI options, refer to the
OpenVMS Record Management Utilities Reference Manual.
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