Document revision date: 15 July 2002 | |
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You initialize a disk or tape volume for one or both of the following reasons:
Before you or any user can write files or data to a disk or a tape volume, you must initialize a volume.
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.) |
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:
1. INITIALIZE | 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.) |
2. MOUNT | Provides the user's process with access to a volume's files or data. |
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.
Task | Description |
---|---|
Load | Insert the media into the drive. |
Initialize | Remove all previous contents from the media. (VOLPRO privilege is required for most operations.) |
Mount | 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. |
Perform file operations | Access files and perform the desired operations on them. |
Dismount | Logically dismount the media and deallocate the device (requires GRPNAM and SYSNAM user privileges to dismount group and system volumes). |
Unload | Remove the media from the drive compartment. |
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 |
where:
device-name | 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.) |
volume-label | 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. |
To initialize a public volume, you must specify the /SYSTEM qualifier with the DCL command INITIALIZE:
INITIALIZE/SYSTEM device name[:] volume-label |
For more details on INITIALIZE command format, refer to the OpenVMS DCL Dictionary.
$ INITIALIZE DUA2: TEMP |
$ INITIALIZE MUB2: 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.
Qualifier | Description |
---|---|
/CLUSTER_SIZE=
number-of-blocks |
Specifies minimum allocation unit in blocks. |
/HEADERS=
number-of-headers |
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. |
/INDEX= position | 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. |
/MAXIMUM_FILES= n | 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. |
/PROTECTION=
(ownership=[:access][,...]) |
Specifies the protection code to be assigned to a volume. See Section 9.4 for details. |
/WINDOWS= n | 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. |
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. |
$ INITIALIZE/HEADERS=100000 DUA3: |
$ INITIALIZE/MAXIMUM_FILES=20000 DUA3: |
$ INITIALIZE/WINDOWS=10 DUA3: |
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 |
For example:
$ INITIALIZE /STRUCTURE_LEVEL=5 DKA300: DISK1 $ MOUNT DKA300: DISK1 /SYSTEM %MOUNT-I-MOUNTED, DISK1 mounted on _STAR$DKA300: |
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 . . . Volume Status: ODS-5, subject to mount verification, file high-water marking, write-back caching enabled. |
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 |
F11V2 indicates that the volume is ODS-2.
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:
|
Initializing volumes for users might be necessary in some circumstances:
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.
Access Type | Gives you the right to... |
---|---|
Read | Examine file names, print, or copy files from the volume. System and owner categories always have read access to tape volumes. |
Write | 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. |
Create | 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. |
Delete | 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. |
Control |
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:
Control access is not valid with tapes. |
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:
Task | Section |
---|---|
Protecting disk volumes | Section 9.4.1 |
Protecting tape volumes | Section 9.4.2 |
Auditing volume access | Section 9.4.3 |
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.
You can change permanently stored protection information in the following ways:
The following sections explain how to perform these tasks:
Task | Section |
---|---|
Specify protection when you initialize volumes | Section 9.4.1.1 |
Change protection after volumes are mounted | Section 9.4.1.2 |
Display protection | Section 9.4.1.3 |
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:
$ INITIALIZE DUA7: ACCOUNT1/PROTECTION=(S:RWCD,O:RWCD,G:R,W:R) |
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.
Qualifier | Explanation |
---|---|
/PROTECTION | The protection you specify with this qualifier overrides any protection you specify with other qualifiers. |
/SYSTEM | 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. |
/GROUP | System, owner, and group processes have read, write, create, and delete access to the volume. World users have no access. |
/NOSHARE | 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. |
The /SYSTEM qualifier grants all users complete access. However, users cannot create directories or files unless you perform one of the following actions:
System managers usually choose the second method. |
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.
Qualifier | UIC | Protection |
---|---|---|
/SYSTEM | [1,1] | S:RWCD,O:RWCD,G:RWCD,W:RWCD |
/SYSTEM/NOSHARE | [1,1] | S:RWCD,O:RWCD,G:RWCD,W:RWCD |
/GROUP | [x,0] | S:RWCD,O:RWCD,G:RWCD,W |
/SHARE (the default) | [x,x] 1 | S:RWCD,O:RWCD,G:RWCD,W:RWCD |
/NOSHARE | [x,x] 1 | S:RWCD,O:RWCD,G,W |
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:
MOUNT/PROTECTION=XAR |
When you specify the XAR option for a file that has an associated
XAR, the protection fields in the XAR are enabled.
MOUNT/PROTECTION=DSI |
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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