Default: POLICY(ALLOW)
When you specify TRK or CYL for a partitioned data set (PDS), the primary quantity includes the space for the directory. When you specify a block length for a PDS, the primary quantity does not include the directory space; the system assigns the directory space outside the primary space assignment.
One volume must have enough available space for the primary quantity. If you request a particular volume and it does not have enough space available for your request, the system ends the job step. Allow for track overflow when computing track requirements.
To request an entire volume, specify in the primary quantity the number of tracks or cylinders on the volume minus the number used by the volume table of contents (VTOC). The volume must not contain other data sets.
Value Range: 0 - 16777215
Default: 4
If PRIMARY specifies the average block length, the system computes the number of tracks for the secondary quantity from the SECONDARY value multiplied by one of the following, in order:
When you specify SECONDARY and the data set requires additional space, the system allocates the specified quantity:
The system can allocate up to 16 extents for a data set on a volume. An extent is space that may or may not be contiguous to other space allocated to the data set. The extents for a data set include the primary quantity space and user-label space.
Note that your program should not write with a disposition of DISP=SHR unless you take precautions to prevent other programs from writing at the same time.
If the requested volumes have no more available space and if at least one volume is demountable, the system asks the operator to mount scratch (nonspecific) volumes until the secondary allocation is complete. If none of the volumes are demountable, the system abnormally ends the job step.
Value Range: 0 - 16777215
Default: 24
Value Range: 0 - 8388607
Default: 0
Value Range: 0 - 65535
Default: 8192
Default: NOROUND
Default: AVEBLK
For example, assume the following space extents (in tracks) are available: 910, 435, 201, 102, 14, 12, and 8.
If your job requests 14 tracks as its primary allocation, and ALX is in effect, the job receives the following 5 extents: 910, 435, 201, 102, and 14.
However, if the job requests 15 tracks as its primary allocation, it would received 4 extents: 910, 435, 201, and 102. The job does not receive the 14-track extent because it is less than the primary space allocation.
Caution: IBM suggests that you use extreme care when coding this parameter. Large amounts of storage could be allocated, depending on how much free space is available at the time the request is made. If you code this parameter, IBM suggests that you also code the RLSE parameter to release any unused space.
Default: None
Default: RLSE
Specifying REDIRECTED_TAPE(TAPE) causes unopened batch allocated data sets that have been redirected from TAPE to DASD to be deleted during final disposition processing. These unopened redirected data sets are deleted regardless of the disposition requested.
Specifying REDIRECTED_TAPE(DASD) causes unopened batch allocated data sets that have been redirected from TAPE to DASD to be processed according to the original disposition, as they would have been if they had been directed to DASD and not redirected to DASD from TAPE.
Default: TAPE
A group-name can identify a single device or a group of devices. A group can consist of devices of the same or different types. For example, a group can contain both direct access storage devices (DASD) and tape devices.
The system assigns any available device from the group. If a group consists of only one device, the system assigns that device. If the group consists of more than one device type, the units requested are allocated from the same device type. For example, if GPDA contains 3330 Disk Storage and 3350 direct access storage devices (DASD), a request for two units would be allocated to two 3330s or to two 3350s.
If a data set that was created using the group-name subparameter is to be extended, the system allocates additional devices of the same type as the original devices. However, the additional devices may not necessarily be from the same group.
If the user is not a time sharing user, or if the SYS1.UADS entry does not contain a unit description, the system uses the unit name specified on the UNIT keyword of the ALLOCxx parmlib member as the default.
The unit description you supply in your dynamic allocation request can override the unit type for a cataloged data set. The unit description from the SYS1.UADS, however, cannot override the unit information in the catalog.
Value Range: 1 to 8 alphanumeric characters.
Default: SYSALLDA, which contains all DASD defined to the system.
The installation must have assigned the name to the device(s) during system initialization, or IBM must have assigned the name.
Unit-name can be a group name. A group-name can identify a single device or a group of devices. A group can consist of devices of the same or different types. For example, a group can contain both direct reel tape devices (3400) and cartridge tape devices (3480).
The system assigns any available device from the group. If a group consists of only one device, the system assigns that device. If the group consists of more than one device type, the units requested are allocated from the same device type. For example, if TAPEGRP contains both 3400 devices and 3480 devices, a request for two units would be allocated to two 3400s or to two 3480s.
If a data set that was created using the UNITAFF subparameter is to be extended, the system allocates additional devices of the same type as the original devices. However, the additional devices might not necessarily be from the same group.
If the name specified by UNITAFF does not exist in the eligible devices table (EDT), the system default is used instead and a warning message is issued.
Value Range: 1 to 8 alphanumeric characters.
Default: Tape generic highest in the device preference table. This generic must be available on every IODF used on the system between this IPL and the next IPL.
Dec | Hex | Size of TIOT | Maximum number of single unit DD Allowed | Maximum number of DDs allowed when every DD requests the maximum number of units (59) |
---|---|---|---|---|
16 | 10 | 16384 (16K) | 816 | 64 |
17 | 11 | 17408 (17K) | 867 | 68 |
24 | 18 | 24576 (24K) | 1225 | 97 |
25 | 19 | 25600 (25K) | 1277 | 101 |
32 | 20 | 32768 (32K) | 1635 | 129 |
40 | 28 | 40960 (40K) | 2045 | 162 |
48 | 30 | 49152 (48K) | 2454 | 194 |
56 | 38 | 57344 (56K) | 2864 | 227 |
64 | 40 | 65536 (64K) | 3273 | 259 |
//TAPEJOB JOB
//STEP1 EXEC PGM=IEFBR14
//DD1 DD UNIT=3490 ** DD requires 20 bytes *
//TAPEJOB JOB
//STEP1 EXEC PGM=IEFBR14
//DD1 DD UNIT=(3490,2) ** DD requires 24 bytes *
//TAPEJOB JOB
//STEP1 EXEC PGM=IEFBR14
//DD1 DD UNIT=(3490,59) ** DD requires 252 bytes *
//TAPEJOB JOB
//STEP1 EXEC PGM=IEFBR14
//DD1 DD UNIT=3490 ** DD requires 20 bytes *
//DD2 DD UNIT=(3490,2) ** DD requires 24 bytes *
//DD3 DD UNIT=(3490,3) ** DD requires 28 bytes *
Value Range: 16 - 64 kilobytes
Default: 32 kilobytes
When YES is specified, and a batch job's enqueue request cannot be satisfied, the system issues messages IEF861I, IEF863I and IEF458D. The job waits, holding any resources it might have acquired. The system operator can choose to cancel the job in response to message IEF458D, or allow the job to continue waiting until the enqueue becomes available. If the operator cancels the job, the system writes an informational message (IEF330I) to the job log.
When NO is specified, the system cancels the job, releases its resources, and issues message IEF211I.
Default: NO
In addition, the system issues message IEF369D (invalid reply) in response to an invalid reply to IEF235D.
Default: WTOR
In addition, the system issues message IEF369D (invalid reply) in response to an invalid reply to IEF455D.
Default: WTOR
Be aware that using the WAITHOLD policy might cause a deadlock situation, particularly when the device is being used by a job that is going to wait. The system does not release any non-sharable devices (that is, non-DASD) that have already been allocated to the job before it waits for required units and volumes. To avoid this problem, do not specify WAITHOLD.
When devices for a job are held during a wait, and a device that was eligible for allocation to the job becomes ineligible for allocation (because of its use by a system utility, for example), the job might fail because it does not have enough devices to complete successfully. Message IEF700I in the job log identifies this failure. Refer to message IEF700I for information about how to respond to this failure.
Default: WTOR
Value Range: 1 - 255
Default: 5
The system is to either cancel the allocation request (CANCEL) or issue a message (WTOR). When WTOR is selected, the system issues the messages listed earlier under WTOR. When CANCEL is selected, the system cancels the allocation request depending on how the request was issued. If a TSO/E user issued the allocation request, the user receives an error message. If a batch job or started task issued the request, the system cancels the job or task, releases its resources, and issues message IEF251I.
Default: WTOR
Note that if all eligible devices are offline, they cannot be brought online without operator intervention. In this case, the system ignores the WAITHOLD and WAITNOH options and issues the WTOR immediately.
Be aware that using the WAITHOLD policy might cause a deadlock situation, particularly when the device is being used by a job that is going to wait. The system does not release any non-sharable devices (that is, non-DASD) that have already been allocated to the job before it waits for required units and volumes. To avoid this problem, do not specify WAITHOLD.
When devices for a job are held during a wait, and a device that was eligible for allocation to the job becomes ineligible for allocation (because of its use by a system utility, for example), the job might fail because it does not have enough devices to complete successfully. Message IEF700I in the job log identifies this failure. Refer to message IEF700I for information about how to respond to this failure.
Default: WTOR
Value Range: 1 - 255
Default: 5
The system is to either cancel the allocation request (CANCEL) or issue a WTOR. When WTOR is selected, the system issues the messages listed earlier under WTOR. When CANCEL is selected, the system cancels the allocation request depending on how the request was issued. If a TSO/E user issued the allocation request, the user receives an error message. If a batch job or started task issued the request, the system cancels the job or task, releases its resources, and issues message IEF251I.
Default: WTOR
Default: NO
Default: NO
Note that the OPEN, FEOV and CLOSE macros allow the specification of a positioning parameter, and that the LEAVE option of these macros is treated the same as RETAIN®.
An AS Tape device that is connected, and possibly used, outside of this allocation's tape management scheme can be "stolen" for temporary use by allocation on a system outside this scheme and cause the volume status for the device to change, unbeknownst to this allocation's scheme. In this case, if the volume had been premounted, or is PASSed/RETAINed, this allocation scheme could then be causing inadvertent read/write activity on a volume. This can result in data loss or data integrity exposures.
If, for a given DD statement, MVS allocation selects an AS tape device and the UCB for that device shows any currently mounted volume to be the required volume for that DD, the system can optionally cause volume verification to occur when an OPEN is performed for that DD.
This becomes a significant consideration if:
Some examples of AS Tape devices that are connected outside the scope of allocation's tape management scheme include:
Default: YES
Default: LEGACY
This setting is useful when there are multiple tape libraries with different numbers of online tape devices. A tape library with, for example, 512 online tape devices would be able to handle more requests than a tape library with only 16 online tape devices. This setting allows MVS Device Allocation to better balance the requests across dissimilar libraries.
Default: EQUAL
Value Range: 0 or 10-999
Default: 90
Default: INCLUDELABEL
Instances of the IEFALC 01 event should be corrected by the installation rather than reported to IBM. For more information about the tracking facility, see z/OS MVS Planning: Operations.
Instances of the IEFALC 01 event should be corrected by the installation, rather than reported to IBM. For more information about the tracking facility, see z/OS MVS Planning: Operations.
In addition to tracking the event, message IEF384I indicates that the data set is uncataloged, but the volume information is not retrieved from the catalog. This message informs the submitter of the job that the JCL should be corrected. For details, see z/OS MVS System Messages, Vol 8 (IEF-IGD).
Instances of the IEFALC 01 event should be corrected by the installation, rather than reported to IBM. For more information about the tracking facility, see z/OS MVS Planning: Operations.
In addition to tracking the event, message IEF384I indicates that the data set is uncataloged, but the volume information is not retrieved from the catalog. This message informs the submitter of the job that the JCL should be corrected. For details, see z/OS MVS System Messages, Vol 8 (IEF-IGD).
Default: FAIL
Default: DISABLE
Default: SERIAL
Default: EXPLICIT