The media that are needed by a BACKUP job can be listed by using the following command:

$ @MEDIA_LIBRARY:LIST_REQUIRED_MEDIA JOB_NAME [OUTPUT_FILE]

The JOB_NAME can be the name of a specific BACKUP job or a group selected by specifying a string containing wildcards. Specifying an asterisk (*) will select all jobs. Optionally the word TODAY or TOMORROW can be provided to select the jobs that would execute on that day. If an output file is specified the data is placed into that file, otherwise it is displayed.

For example, to list all the media required for jobs with names starting in FULL use the following command:

M$ @MEDIA_LIBRARY:LIST_REQUIRED_MEDIA FULL* ========================================================= FULL_ISE0 Start time: 8-JUN-1996 08:00 Backup of DISK$ISE0 Media required for this Job: Media Location Attchd Type ----------- ------------------------- ------ --------- 742;0 Library TK50 743;0 Library 742 TK50 752;0 Library 742 TK50 ========================================================= FULL_ISE1 Start time: 8-JUN-1996 08:00 Backup of DISK$ISE1 Media required for this Job: Media Location Attchd Type ----------- ------------------------- ------ --------- 751;0 Library TK50 754;0 Library 751 TK50 756;0 Library 751 TK50 767;0 Library 751 TK50

2.2.4 Operator responses

1. Perform the request and let the system detect the response
2. REPLY/TO=request_num
3. REPLY/ABORT=request_num

The first two tell the system to proceed and check that the correct medium was mounted. If you mistakenly mounted a wrong medium it is immediately dismounted and you are given an opportunity to mount the correct one again. The third option will terminate the mount request and cause the job to fail. Requests from MEDIA look like this:

%%%%%%%%%%OPCOM, dd-mmm-yyy hh:mm:ss.cc %%%%%%%%%% Request REQUEST-ID, from user USERNAME message text...

For example:

%%%%%%%%%% OPCOM 15-JAN-1996 12:30:07.21 %%%%%%%%%% Request 21, from user HOSKINS Please mount volume 1200 in device MTA1: External label 1200, density 6250 bpi, from library, for readonly

In this example a possible response will be to mount the reel in drive MTA1 and let the system react to the completion automatically. The system would then verify that the correct reel is mounted on the drive and perform the requested activity. In this example, the system would respond:

%%%%%%%%%% OPCOM 15-JAN-1996 12:32:03.33 %%%%%%%%%% Request 21 was satisfied

This indicates that the system discovered that you had mounted the tape reel on the tape drive. Once the medium has been mounted the system will verify that it is the correct medium by reading the encoded label and comparing it with the internal label in MEDIA DATABASE.

If the system detected the requested medium already in place on the drive, none of the messages would appear because the system would automatically comply with the request without notifying the OPERATOR.

In many cases, it is impossible for MEDIA to determine that the correct medium is mounted on a drive by reading the internal label of the medium. The most common case of this is for a blank, newly added media. The reply required is only applicable to new media the first time they are initialized. Such entries are usually marked BLANK (i.e. no data or label recorded on medium). In this type of situation MEDIA will alter the prompt to insist on a REPLY/TO command being used by the OPERATOR to verify that the correct medium is indeed on the drive. The OPCOM message in such a situation is:

%%%%%%%%%% OPCOM 15-JAN-1996 12:32:17.20 %%%%%%%%%% Request 21, from user HOSKINS Please mount volume 1200 in device MTA1: (reply required) External label 1200, density 6250 bpi, from library, for readonly

When the OPERATOR has found the tape and mounted it, he would answer using the below command. Nothing happens until the OPERATOR answers the request.

$ REPLY/TO=21

and the system would display the following:

12:35:00.19, request 21 was completed by operator _TTA3:

The following message will appear when the job has been successfully completed. ⁸

%%%%%%%%%% OPCOM 15-JAN-1996 12:40:19.10 %%%%%%%%%% Message from user HOSKINS Done with medium 1200

If for some reason, request 21 couldn't be completed, the OPERATOR could abort the request by typing:

$ REPLY/ABORT=21

The following message would appear to indicate that the job failed.

%%%%%%%%%% OPCOM 15-JAN-1996 12:40:19.10 %%%%%%%%%% Message from user HOSKINS Done with medium 1200, job FAILED

2.3 MEDIA pool management

All media are classified into three pools; allocated, available and released. The pools can be viewed using either MCL or DCL. These two methods will be examined in this section.

2.3.1 Viewing the pools in MCL

Viewing media by pool in MCL can be accomplished by identifying the pool in the INCLUDE field of the Set Media Search Criteria form and subsequently using the Select medium option to display the desired pool.

The three pools can be viewed either by entering /POOL=AVAILABLE, ALLOCATED or RELEASED or simply entering AVAILABLE, ALLOCATED or RELEASED in the INCLUDE field of the Set Media Search Criteria form.

For example, if you were interested in finding out which media were in the available pool so you could allocate some, you would first choose Selection and Display Controls from the Media Library functions menu. Next, you would select Set Media Search Criteria from the Selection and Display Controls menu. The form shown in Figure 2-2 will appear.

Figure 2-2 Search Criteria

As the figure illustrates, the INCLUDE field contains the phrase */INCLUDE = AVAILABLE. This will enable the display of media in the available pool only. The resulting display would be similar to Figure Figure 2-3, depending on the available media on your system.

Figure 2-3 Select a Medium Menu

2.3.2 Viewing the pools in DCL

Table 2-1 Pool movement commands

Command	Function
ASSIGN_TO	Will move a medium from any pool to the allocated pool. This is the recommended way of moving a medium from one user to another. All current medium characteristics are left intact.
RELEASE	Will move an allocated or available medium into the released pool.
RE_USE	Will move a released or allocated medium into the available pool.
DELETE	Will permanently remove a medium from any pool.
ADD	Will (by default) add medium to the available pool.
CATALOG	Will (by default) add medium to the allocated pool.

The pools can be viewed by using the directory command. The typical commands are described below.

There are two ways to view the available pool. They are:

1. In queue order (first in, first out order)

   MEDIA AVAILABLE DIRECTORY

   
   

2. Sorted by medium name

   MEDIA */POOL=AVAILABLE DIRECTORY

   
   

There are two ways to view the released pool. They are:

1. In queue order (first in, first out order)

   MEDIA RELEASED DIRECTORY

   
   

2. Sorted by medium name

   MEDIA */POOL=RELEASED DIRECTORY

There are four ways to view the entire allocated group. They are:

1. Sorted by date allocated

   MEDIA ALLOCATED DIRECTORY

   
   

2. Sorted by medium name

   MEDIA */USER=* DIRECTORY

   
   

3. Sorted by user name

   MEDIA */USER=%* DIRECTORY

   
   

4. Sorted by external name on medium

   MEDIA *;0/USER=* DIRECTORY

Any number of column selectors can be used with the DIRECTORY command to see any particular parameter of interest. Please review the Reference Section for a description of the DIRECTORY command and for more details about the available column selectors.

2.3.3 Adding media

The MEDIA ADD command is used to add media into the available pool. The basic command format is:⁹

$ MEDIA MEDIUM_NAME ADD/QUALIFIER

In most cases, you will be adding blank media to the database in a continuous series of external ID numbers, and can substitute a range specification for the medium name. For example, to add the range of numbers from B001 to B010, type:

$ MEDIA B001:10 ADD

The most common qualifiers you will use are listed in Table 2-2.

Table 2-2 Common ADD qualifiers

Qualifier	Description
/LOG	as each medium is added a message is displayed to that effect.
/TYPE=word	indicates that the added medium is of the this type (i.e. TK50, TAPE etc.).
/LOCATION=word	indicates that the added medium is stored in the specified location.
/LENGTH=feet	indicates that the added medium is of the specified length (i.e. 1200ft, 2400ft, etc.).

The /TYPE qualifier could be a specific term, such as TA90, rather than just TAPE, to avoid confusion. Please check with the MANAGER for information about the allowed values for these qualifiers.¹⁰

2.3.4 Deleting media

$ MEDIA MEDIUM_NAME DELETE/QUALIFIER

You can delete more than one tape with a simple command by supplying a list of media. For example, if you wanted to delete the media R005, X00022, and X00025 you would type

$ MEDIA R005, X00022, X00025 DELETE

Please see the Reference Section for a list of qualifiers that can be used with the DELETE command.

2.3.5 The DIRECTORY command

The MEDIA DIRECTORY command can be used to look at either the summary information (medium name, location, etc.) or the contents information (file names, dates, etc.) of a medium.

2.3.5.1 Displaying header information

To display header information about media:

$ MEDIA MEDIUM_NAME DIRECTORY/QUALIFIER

2.3.5.2 Listing media contents

$ MEDIA MEDIUM_NAME>FILE_NAME DIRECTORY/QUALIFIER

Please see the Reference Section for a list of qualifiers that can be used with the DIRECTORY command.

2.3.6 Automatically re-using media

The process of moving released media into the available pool¹¹

can be done by setting up a (described in a later chapter) that issues the following command once a day.

MEDIA RELEASED RE_USE/BEFORE=TODAY-10-00/EXPIRED

When a medium is released, the expired date is set and the medium is re-classified as released. The above command then scans the entire released pool and moves to the available pool any medium that have an expiration date of 10 days prior (TODAY - 10 days). This type of command can only be issued by a MANAGER.

To increase security, it may be useful to actually re-initialize and/or erase the entire medium before it is made available.

A maintenance command procedure can be used to add this procedure if it is not already present on your system. The following command will create such a job.

@MEDIA_LIBRARY:BCKMGR_STANDARD_PROCS ADD_AUTO_RE_USE Created AUTO_RE_USE

2.3.7 Automatically expiring media

MEDIA ALLOCATED RELEASE/BEFORE=TODAY/EXPIRED

This will scan all allocated tapes and release those that have expiration dates prior to today. This type of command can only be issued by a MANAGER.