Start up a new server.

The start command will start up a MEDIA_SERVER process. This type of start will use the attributes of the current user rather then the server default attributes. It is essential that the server process be started up via the SYS$STARTUP:MEDIA_STARTUP procedure during a system boot rather interactively via this command.

Format

START

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The start command uses the SYS$CREPRC system service to spin off a detached process that is the MEDIA_SERVER process.

Stop the server process.

The STOP command instructs the server process to do a normal termination.

Format

STOP

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On exit a message is sent to the operator console to the effect that the server process is exiting.

8.1 Introduction

The first parameter file is required, the second is optional. If the same parameter is defined in both files the one in MEDIA.VAR will be used. On a cluster system, it is advantageous to put the CPU specific device characteristics in MEDIA.VAR in the CPU specific manager directory, and place all the cluster wide queue definitions in MEDIA2.VAR in the cluster common manager directory.

The MEDIAS SET command is used to change any particular parameter. This file is a normal text file and can be edited at any time to make any necessary corrections. Once corrections have been made to this file, the server process needs to be restarted to take these changes into account. To do this, use the following command:

$ MEDIAS RESTART

Normal use of the SET command will cause the server to restart as needed. If a situation arises that the server needs to be forcibly restarted this last command can be used. The various parameters listed in Table 8-1 in the following sections.

Table 8-1 Parameters Names

Parameter	Description
ALIAS	ALIAS names for drives associated with known types
ANSI_REV_LEVEL	3 or 4 Revision level of tape labels
AUX_COM_FILE	Name of auxilary command file
BGR_BATCH	Do or do not allow batch use of device commands
CENTRAL	define MEDIA database location
COMPLETION	Do or do not send messages on job completion
DEFAULT	define defaults attributes
ERROR	Do or do not monitor system error activity
INCORE	Do or do not allow use of INCORE features
INITIALIZE	define initialization mode
INTERACTIVE	Do or do not allow interactive use of device commands
LOCK_DEVICES	Do or do not request server process to allocate all devices
MNT_MESSAGE	Mount request message format controls
MOUNT_RETRIES_DISK	The number of times an automatic retry is carried out on a disk before an operator is required.
MOUNT_RETRIES_TAPE	Same as MOUNT_RETRIES_DISK except for tapes.
OPCOM	Do or do not send messages on job submission
QUEUE	define a device/queue relationship
SLAVE	Do or do not server process is enabled
SVR_HOME	define the server home directory
SVR_CENTRAL	define the shared server file location
synonym	device name synonyms
type	define drives associated with known types
TIMEOUT	define the allocation time out period
UNLOAD	Do or do not allows all dismounts to be forced to unload
USER_ADD	Do or do not allow non-operator catalog/add commands
VDISK	defines location of disk portions of VAULT database
VLT_CENTRAL	defines location of VAULT database
VLT_KEEP_ERASED	Do or do not enables erased records to be processed

8.2 Parameter descriptions

For each device type specified in a QUEUE parameter or used anywhere in the medium database, a corresponding ALIAS name may be supplied. This parameter associates physical devices with the more generic name used in the database.

Format

ALIAS_nnnn = [TAPE,]device_name:[,LENGTH=n] [,DENSITY=(m,..)][,LOCK][,UNLOAD] or DISK,device_name:[,LOCK][,UNLOAD]

Attribute	Meaning
type|n	device type and member number
TAPE	indicates a sequential tape device
DISK	indicates a direct access disk device
device_name:	can be either ddcu:, the physical name of a device or @com_file:[param]:, a com file which manages the ALLOCATION/DEALLOCATION of a device defined as a dynamic device(for information on how to create such a com file, see Appendix C)
LENGTH=n	maximum length specified tape drive can handle
LOCK	request server to allocate this device
UNLOAD	unload the volume on dismount
DENSITY=m	available densities (800, 1600, 3200, 6250, 6666, 10000, 39782, 42500 or 79564)

Examples

     ALIAS_MTA0 = TAPE,MTA0:,DENSITY=(800,1600) 
      

     ALIAS_MSA0 = TAPE,MSA0:,LENGTH=1200,DENSITY=1600,LOCK 
      

 
     ALIAS_DBA0 = DISK,DBA0: 
      

     ALIAS_DBA1 = DISK,DBA1: 
      

 
     ALIAS_DYN01 = DISK@DYNAMIC:ABC 
      

 
   
     ALIAS_MUA0 = TAPE, MUA0: 
      

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The device selection process performed during the allocation step examines the LENGTH and DENSITY specifications (if supplied) and compares them with the known attributes for the medium being used. Only a drive which meets the known requirements will be selected. If this turns out to create an impossible situation, the request is aborted and a message is issued to that effect.

The LOCK parameter will allow for selective locking of devices by the MEDIA-SERVER process. This will cause the server process to allocate the drive and only release it to a MEDIA ALLOCATE command. This differs from LOCK_DEVICES parameter which will lock all devices known to the MEDIA Librarian. The lock condition will prevent any allocation of the specified drive from being performed without using the MEDIA Librarian.

The 6666 density applies to TK50 cartridges and 10000 applies to TK70 cartridges. The 39782 density applies to a TA90 cartridge. The 42500 density applies to TF85 cartridges. The 79564 density applies to a TA90E cartridge.

The UNLOAD flag setting requests that the drive be unloaded whenever a volume is dismounted. If the UNLOAD PARAMETER is set to 2 or 3 the server resident information is also reset during the dismount.

Note This lock flag is only used during the initial creation of the MEDIAS.DAT control file.

After the initial setup use the

MEDIAS> SET/DEVICE MTA0:/LOCK MEDIAS> SET/DEVICE MTA0:/UNLOCK

to change the lock flag.

The ANSI_REV_LEVEL parameter controls the revision level used when initializing a tape. This parameter only affects the MEDIA INITIALIZE command.

Format

ANSI_REV_LEVEL = 3 or 4(D)

Examples

 ANSI_REV_LEVEL = 3 
 
      

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Revision level 4 moves the VAX/VMS protection codes from the VOL1 label record into the VOL2 record. This allows complete implementation of the ANSI owner identifier in the VOL1 record.

The presence of a AUX_COM_FILE parameter will cause all MEDIA Jobs to execute this command file before and after all the device commands included in the standard prefix and postfix operations implicitly included by the creation of the MEDIA batch job. The AUX_COM_FILE parameter is cluster wide because of the server, therefore you cannot have the file in SYS$SPECIFIC.

Format

=

AUX_COM_FILE file_name

Examples

 AUX_COM_FILE = "MEDIA_LIBRARY:AUX_OPS" 
 
      

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The command that is added into the .MCM temporary command file has the following format:

$ @aux_file command mode type external location density

The COMMAND parameter is one of the following words: ALLOCATE, INITIALIZE, MOUNT, DISMOUNT, UPDATE or DEALLOCATE. The MODE is either the word BEFORE or AFTER. The TYPE is the type word contained in the database for this medium. The EXTERNAL parameter is the external id. of the medium. The LOCATION parameter is the storage location of the medium. The DENSITY parameter is the recorded density of the medium.

The purpose of this command file is to allow other related standard operations to be performed in step with the associated MEDIA device commands. A sample COM file (MEDIA_LIBRARY:AUX_OPS.COM) has been included. This sample procedure will print a label at the end of each job. Other functions that can be added are, for example, DCL that will send instructions to a juke box type device to load a particular cartridge prior to mounting it.

The BATCH parameter is a yes / no variable. It determines whether any device command can be executed in batch. Disabling this mode will also disable all batch job commands.

Format

BATCH = O(no) or 1 (yes)(D)

Examples

 BATCH = 1 
 
      

The CENTRAL parameter is an alternate way of locating the MEDIA database. If used, it will override the logical name MEDIA_LIBRARY for the files MEDIA.DAT, *.SDR, *.TDR and *.BJL.

Format

CENTRAL = location

Examples

 CENTRAL = ALPHA"SYSTEM MANAGER"::DBA0:[MEDIA] 
 
      

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This can be especially useful in a DECnet environment where the MEDIA database is to be shared. But a separate copy of the various executable images (those kept in MEDIA_LIBRARY) is kept on each node. This is an easy way to disguise the actual library location from the users.

The COMPLETION parameter controls whether a message is sent to the operator on completion of a MEDIA job.

Format

COMPLETION = O (no) or 1 (yes)(D)

Examples

 COMPLETION = 0 
      

The DEFAULT parameter establishes default values for medium allocations via UNKNOWN or use of the /NEW qualifier. These defaults are also used by the MEDIA ADD command if no other default records are found. ¹

Format

DEFAULT_TYPE = name

DEFAULT_LOCATION = name

DEFAULT_DENSITY = bpi (tapes only)

DEFAULT_LENGTH = reel_length (tapes only)

DEFAULT_EXPIRATION = combination_time

Examples

 
 DEFAULT_LOCATION = LIBRARY 
 
      

 DEFAULT_EXPIRATION = "TODAY+365-00" 
 
      

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Whenever an allocation from the available pool is requested and any of the TYPE, LOCATION, DENSITY or LENGTH is not specified they are picked from the value of these parameters. Once a medium has been allocated from the pool the expiration date (if a default expiration exists) is set.