Device depot exit MARENEX6

With the introduction of support for archive systems it became necessary to differentiate between automatically operated devices and devices controlled manually by a human operator. For this reason, device depots were introduced to BS2000 (NDM); these can be managed with the aid of the operator commands ADD-DEVICE-DEPOT, SHOW-DEVICE-DEPOT and REMOVE-DEVICE-DEPOT.

When tapes are requested, the device depot must be specified in addition to the volume type; an appropriate device must be used by NDM. In the case of a scratch application, MARENUCP must also know which location (archive system or manually operated archive) the tape must be selected from for processing.

This exit makes it possible, to define the device depot in which a device is to be used and set the HOME-LOCATION with the same name for tape selection.

A reservation file created with MARENLM is evaluated immediately before the exit for the device depot.

The device depot exit is called in the following cases:

• a command SECURE-RESOURCE-ALLOCATION DEVICE without a LOCATION parameter was called

• a scratch request is being processed.

When the call is issued, the following information is passed to the exit or returned by it in the form shown below:

FILENAME	File name (either the file name as specified via a new parameter in the SECURE-RESOURCE-ALLOCATION command, or the DMS file name in case of a DMS scratch request)
LATSN OWNERID OWNERACC CRJOB LACPU	TSN of the calling task User ID of the calling task Account number of the calling task Job name of the calling task Name of the system on which the call was issued (HOSTNAME from the MARENCP start procedure)
HOMELOC	Value of the system-specific parameter DEFAULT-HOME-LOC

The catalog entry field USERFELD passes or returns the following (see note):

DEVTYPE NUMDEV DEPOT1 NUM1 DEPOT2 NUM2 DEPOT3 NUM3 DEPOT4 NUM4

8 Byte 1 Byte 8 Byte 1 Byte 8 Byte 1 Byte 8 Byte 1 Byte 8 Byte 1 Byte

Device type as specified in request Number as specified in request Suggested device depot Number of devices as specified in request empty empty empty empty empty empty

DEVICE-DEPOT/HOME-LOCATION is defined by the device depot exit. If two or more devices are requested (only possible with the SECURE-RESOURCE-ALLOCATION command), the devices can belong to different device depots. If more than one device is to be reserved, this is done device by device, because of the internal processing in NDM. The NUMDEV catalog entry field always has the value 1.

Fields DEPOT2/NUM2 through DEPOT4/NUM4 currently have no meaning.

If blanks are returned instead of the location, MARENUCP determines the location from the number range (fields NUMMANFV and NUMMEND). MARENUCP determines the first tape in the number range and designates the
tape’s FREE-LOCATION as the required location.

The following additional conditions apply:

• Only one number range can be returned for device depot exit MARENEX6, even if more than one device is requested.

• If no tape is found in the number range, message MARUP97 is output.

Passing parameters

The following information is passed to the device depot exit:

Register 1	A(parameter area) The parameter area comprises a word containing the address of the catalog entry.The individual catalog entry fields can be addressed symbolically via the dummy section MARENA.
Register 13	A(save area) The save area provided by MAREN is 18 words long.
Register 14	A(return) For returning directly to MAREN.
Register 15	A(exit routine) Start address of the called exit routine.

All other registers are set to “binary zero”.

Return codes

The device depot exit returns the following return codes in register 15:

Register contents	Meaning/reaction from MARENUCP
0	The values contained in the USERFELD field in Depot1-4 and NUM1-4 are to be used. For the format of USERFELD, see above.
other	The following rule applies: If a tape is specified in DEVTYPE and an archive system is available, the name of the archive system’s location is used as the depot name. If more than one archive system is available, the one specified first in the MAREN location table is used. Otherwise the location specified in the system-specific DEFAULT-HOME-LOC parameter is used.

Notes

• When a free tape is requested, the exit MARENEX1 is called after MARENEX6. If a location is specified in both cases, the information must not be contradictory.

• Only MARENEX1 can refuse a request (not MARENEX6).

• The location names returned by MARENEX6 must be compatible with the existing device depots.

• The USERFELD catalog entry field is reset to its original contents after the return.