The files for REPORT are:

File name	Contents
MEDIA_LIBRARY:REPORT.EXE	Main command executable.
MEDIA_LIBRARY:MEDIA_REPORT.CLB	Report definitions.

3.1.7 Queues

As installed, MEDIA sets up a queue, SYS$TAPE, for use with TAPE type media. As MANAGER you are responsible for designing queues to help your system run smoothly. In VMS there are two basic types of queues: generic queues and execution queues.

The relationship between these two types is shown in Figure 3-1.

Figure 3-1 Generic and Execution queues

An execution queue is a queue through which the job ⁸ MEDIA selects a queue based on the TYPE to QUEUE association defined in the parameter file. It is essential that the queue selected execute on a node that has physical access to the needed tape or disk drive to complete the medium processing.

A generic queue is an intermediate queue that holds a job until an appropriate execution queue becomes available to initiate the job. Users can submit jobs to a generic queue, and the generic queue then directs the job to an appropriate execution queue; alternately, users can submit jobs directly to an execution queue.

Each TYPE category can be instructed to use its own queues: TK50 cartridge jobs go into a SYS$TK50 queue, 9 track tape jobs into a SYS$TAPE queue. In a homogeneous cluster with four HSC tape drives and two VAX CPUs, one approach would be to have a common generic queue (SYS$TAPE) feeding two execution queues, one on each node. Each execution queue would have a job limit of two. This would allow two jobs to execute on each node.

In a cluster where all the tape drives are directly connected to one node, it is important to use an execution queue that executes on that node. A MEDIA job command executed on any member of the cluster would thus create batch jobs that would execute in this queue. When the job starts, it would then run on the node where the tape drive is located.

3.2 Considerations before installing MEDIA

As you install and run MEDIA there are certain issues that you should consider in your design of the system. Some of the things you should think about before you start are:

• the style of library organization you want
• the level of access that users and operators will be given
• the priority levels that you want to assign to various jobs

This section is intended as a basic collection of questions you should ask before you start to install the system, with some suggestions selected from the experiences of different sites. There are no right answers. If you change your mind about something later, you can make changes in the system configuration, but it not as easy as planning ahead.

3.2.1 Library organization

At most sites, the MEDIA library has grown erratically. Often there has not been a master plan, or if there was a plan, it was designed around the limits of the room or the tracking system available at the time. Now is the time to sit down with the people who actually handle the media and figure out what will work best. MEDIA can be set up to facilitate a library that your site needs now and in the future.

The most basic questions to ask about your library are:

• Where and how are the media stored?
  MEDIA does not require any particular storage arrangement. It is useful to arrange your storage to facilitate locating and retrieving of media by the operator.
• What labeling conventions are used?
  MEDIA does not require any particular labeling method. The most common scheme is to label the media with a serial number, possibly with a letter prefix. Often, this serial number is the same as that of the storage bin or slot in which the medium is stored. A simple scheme will make the operator's job much easier.
• What numbering schemes are used?
  You might have all backup media stored in rack 3 and marked with the date of the backup. You might have all media numbered from 1000 to 9999. You might maintain a notebook containing a handwritten log of all media activity and labels. In all cases, you might want to re-assess these methods in light of the MEDIA system, and consider what future demands will be placed on the computer center.
• How is your current library designed?
  You might have all your media hanging in racks in a storage area adjacent to the computer room. You might not have any centralized storage of media, but each user keeps track of his own. In all cases, it is important to make the job of finding a medium and loading it on a drive as easy as possible. In MEDIA there is a LOCATION field. This should be set to an accurate description of the storage location (i.e. CABINET 3, RACK 4, or ROOM 432).
• How are you currently labeling media?
  You might be putting a new label on each media as it is used to indicate what the media now contains. You might be keeping a card file for all the media in the library. With the addition of MEDIA you are adding an on-line database to track this information. As a result, all that is required is to attach a permanent identifier to the outside of the medium and to enter that identifier into the database. Once that is done the system will automatically keep track of the changing contents of the medium. All comments and similar information is kept in the on-line database.
• Do you have special subgroups of media that you keep physically separate or color code to avoid mix ups?
  You might have color coded your tapes, red for full backups, blue for incrementals. When adding such media to the MEDIA database, you might want to use different numbers and set the TYPE word for each to a different value (i.e. use RX23 and CDROM).
• Do your users write to their own tapes or use library tapes?
  You might require that all tape processing be done by the operations staff. In this case, set the MEDIA.VAR control parameters to disable users from doing this type of activity. You might allow users to enter the computer room and mount their own media. In this case, set the control parameters so that users can catalog and manage their own media.
• Are you satisfied with your current system?
  If you are just installing MEDIA for the first time, you might want to consider whether your current methods are due for a major overhaul. In many sites the tape/disk library has grown from a modest beginning to a current state of chaos.
• Are your users and operators satisfied?
  You might consider surveying your users and operators to see if they are happy with the current arrangements and what improvements they might like.
• Have you allowed for expansion?
  A very important consideration is that of expansion. Most sites experience requirements to keep track of more and more data offline. Be sure that the numbering and storage scheme adopted can handle new media as they arrive.
• Has your work pattern changed so that the system should be reorganized?
  Library operations may have changed from an emphasis on backup jobs to one of emphasis on generations of data tapes. It is useful to organize the job queues on your system to match the type of tape/disk activity you are doing. You could place all backup jobs in a special queue that has a high priority. All data genaeration could be routed into a job queue that controls a drive dedicated for this purpose.
• Can anything be changed to make it easier or faster to handle or track media?
  Such considerations as a small rack adjacent to the drive can greatly simplify staging of media to and from the drive.
• Does your current system allow easy tracking for audits?
  MEDIA maintains a log file which shows all tape/disk drive activity.
• Simple check in and out procedures for media just temporarily on site?
  MEDIA that are just going to be processed once can be easily handled by the USER mode temporary catalog entry.
• Do you routinely send media off site?
  You might send your media off site for safe-keeping. With MEDIA you can mark each off site medium. If a user or operator attempts to request such a medium to be mounted, an error message is issued indicating that this is impossible.
• Are you currently manually pulling out the available media and hanging them separately for re-use?
  You might be moving all available (or scratched) media into a separate rack. With MEDIA this is unnecessary. The system will automatically keep track of the condition of every medium in the database. Requests for an available medium will automatically select a medium and inform the user of the external identifier.
• Do the operators have to check more than one location for a requested medium?
  With MEDIA the storage location is passed to the operator during the mount request.
• Should the current MEDIA library scheme be used as is, or is this a good time to change it?
  This might be a good time to completely change it to reorganize the library to the current situation and expected future demands.

One of the first things to think about in organizing your library is the numbering system. There is no requirement to label or store different subgroups of media separately when you use MEDIA. The simplest and most secure system is to use a continuous series of alphanumeric numbers. For security purposes, tape names should not be the same as job names.

Each medium can have as many as three different names associated with it: the external ID, the internal ID, and an alias.

• The external ID or serial number is the alphanumeric character string marked on the outside of the medium. It is used by the operator to identify the medium in the media library. The external ID for removable disk packs can consist of a maximum of nine characters. However, for tapes, a maximum length of six characters is recommended since their internal labels can only be six characters long. For tapes used with VMS BACKUP ¹ the label should meet the requirements of that utility. The label checking routines in that utility reduce the effective label to just 4 digits.
• The internal ID is the name magnetically encoded on the medium itself and is used by the computer to verify that the correct medium has been mounted by the operator. Usually, this is the same as the external ID.
• The alias is the descriptive name that a user assigns to the medium and uses to refer to it. Commands can be issued based on this name, and MEDIA will translate the operator request to refer to the external ID. The alias can be any alphanumeric combination of 1 to 21 characters.

A version number follows the alias in the directory listings, separated from it by a semicolon, in the format aaaaaa;n. The version number reflects the number of different media that have been given the same alias.

The version number of a medium is 0, if an alias has not been provided. When the medium is named, the version number starts as 1. As new media are assigned using the same alias, the version number is incremented to create a new name on each assign operation.

If you already have a numbering system in use that satisfies your site's needs, you can incorporate it, as is, into the MEDIA library. If you are like many sites and have the remnants of several numbering systems, none of which satisfy anyone, you can redesign the numbering system, add the existing tapes into the new system and have MEDIA track the new external and internal ID. Because MEDIA keeps track of all three identifiers, you can catalog existing tapes into a new continuous numbering system and simply note the old ID number under the comment field.

As an example, at one large data center with a special requirement, the tape library is numbered from A001 through Z999. Because corporate policy requires that the current set of backup tapes be sent off site as part of a disaster recovery plan, the library has been designed with external clues as to which tapes are dedicated to users and which to the system. The tapes from A to M are user tapes: N to Z are backup tapes. This makes it a little easier for the operators to pull the backups and send them off site.

3.2.2 Levels of access

Another area to be considered is that of access to commands and to media.

The system identifies three types of users:

1. Managers ¹⁰ can access all media
2. Operators ¹¹ have "read only" access to all on-line information
3. All other users can access their own media and any media set to general access. Control is based on the UIC of the person accessing the medium.

As a MANAGER you need to think about security requirements versus user needs for access to common data. The individual user will set the level of access for each of his own media. You set the protection for the system tapes. Is there any data that must be maintained as private or extremely restricted access? Do you have payroll information or personnel records that must be protected from unauthorized access? Do you have user groups on site that might need common access to data at different levels of protection?

There are certain tasks that can be done by either the MANAGERS or the OPERATORS depending on how you set up the privilege structure. How much responsibility do you want the operators to have for managing the DATABASEs in MEDIA ? Should the MANAGERS or the OPERATORS be responsible for error checking the media? For maintaining the available pool? Re-allocating prematurely released media for the users?

3.2.3 Granting access using VMS AUTHORIZE

Only a MANAGER may grant access in MEDIA. This is done using the VMS AUTHORIZE command. MEDIA recognizes the identifiers media_operator, and media_manager which are specific to the software. These will only affect operations within MEDIA. MEDIA also recognizes the VMS identifiers OPER for OPERATORS and SYSPRV, BYPASS, and SYSTEM_UIC for MANAGERS.

In order to grant authorization to a user, enter the following series of commands:

$ RUN AUTHORIZE

The UAF> prompt will appear:

UAF> ADD/IDENTIFIER MEDIA_OPERATOR UAF> GRANT/IDENTIFIER MEDIA_OPERATOR CJOHNSON UAF> EXIT

This procedure grants OPERATOR privilege to user CJOHNSON. The media_operator identifier could be replaced with media_manager in order to grant MANAGER privilege.

3.2.4 Priority

You also set the levels of priority for all the queues. You need to look at the workload of your site, the system usage and set guidelines for the availability of high priority or low priority queues. You also need to think about possible exceptions to the general guidelines.

Does your site run payroll jobs that must complete by a certain time or people won't get their paychecks on time? Are there other jobs that must run ahead of anything else on a regular basis? Are there jobs that can routinely be relegated to off peak hours for processing? Do you have jobs that must run before a particular time so that the results can be transmitted or the tape physically sent to another site in a different time zone?