Server versus nonserver mode

Dump job can be run in either server or nonserver mode. When dump job is run in server mode, a dump job server address space is started to allocate the tape device. All tape–related functions such as reading or writing to the tape are done from the dump job server address space. When dump job is run in nonserver mode, the tape device is allocated by JES3, and all tape–related functions such as reading or writing to the tape are done from the JES3 global address space. Dump job tapes created by nonserver mode can be restored in server mode and dump job tapes created by server mode can be restored in nonserver mode. Note, however, that a selective restore (*START,DJ, J=jobno,(OLD)) from a multiple volume dump tape may fail during end of volume processing if the dump was created before the server mode support was installed.

The following table compares running dump job in server and nonserver mode.

Table 1. Dump Job in Server and Nonserver Mode
Server Mode	Nonserver Mode
All access to the tape data set is done in the dump job server address space.	All access to the tape data set is done in the JES3 global address space.
Supports standard label and unlabeled tapes.	Supports standard label and unlabeled tapes.
For standard label tapes, a unique data set name is generated and cataloged. As a result, the operator does not have to remember the list of volumes when restoring the jobs from tape.	No unique data set name is generated or cataloged. The operator must know which volumes need to be mounted when restoring jobs from tape.
Standard data management services (OPEN, CLOSE, EOV) are used to process the tape data set.	Standard data management interfaces are not used to process the tape data set.
Tape devices in the IBM® 3494 and IBM 3495 tape library data server can be used.	Tape devices in the IBM 3494 and IBM 3495 tape library data server cannot be used.
Supports 9-track tapes; does not support 7-track tapes.	Supports 7-track tapes and 9-track tapes.
The device used by dump job does not have to be defined to JES3, but it can be defined to JES3 if you prefer. In addition, a generic device name (for example, 3490) or an esoteric device name (for example, TAPE) may be specified on the *CALL command. If you have tape DEVICE statements in your initialization stream for use only the dump job, you can remove these statements when you decide to run only the dump job in server mode. To remove tape DEVICE and SETNAME statements from the initialization stream you must perform a JES3 hot start with refresh. If you want JES3 to continue to manage tape devices for jobs in execution but no longer need them for dump job, you can remove the DTYPE, JNAME, and JUNIT parameters from the tape DEVICE statements and perform a hot start with refresh. If you change your mind and want to add them back, this can also be accomplished by performing a hot start with refresh.	The device used by dump job must be defined to JES3 through a DEVICE statement and must be defined as a shared device. That is, it must be defined as a JES3 global device through the DTYPE, JNAME, and JUNIT parameters and as an execution device through the XTYPE and XUNIT parameters.
If the device is defined to JES3, it must be varied online as an execution device on the JES3 global. For example, if you want to use device 560 for dump job and SY1 is the global, you must issue the following command to vary the device online: `*V,560,ON,SY1` If the device is not defined to JES3, then the following MVS™ VARY command must be issued: `VARY 560,ONLINE`	The device must be varied online as a global device. For example, if you want to use device 560 for dump job, you must issue the following command to vary the device online: `*V,560,ON`
Dump job can be canceled by doing one of the following: Issue a CANCEL,DJ command (if there is only one DJ DSP active). Issue a CANCEL,J=`jobno` command (if there are multiple DJ DSPs active). Issue a *CANCEL,DJ`devnum` command (if there are multiple DJ DSPs active). `devnum` is the device number assigned to the DJ DSP. Issue an MVS CANCEL command to cancel the server address. You cannot cancel the dump job DSP by device number.	Dump job can be canceled by doing one of the following: Issue a CANCEL,DJ command (if there is only one DJ DSP active). Issue a COMMAND,J=`jobno` command (if there are multiple DJ DSPs active). Issue a CANCEL,`devname` command. Issue a CANCEL,DJ`devnum` command (if there are multiple DJ DSPs active). `devnum` is the device number assigned to the DJ DSP.
The OLD parameter is not supported on the *CALL command when restoring jobs from tapes. The tape will always be rewound before being processed.	The OLD parameter is supported on the *CALL command when restoring jobs from tapes. This allows you to bypass the initial rewind that normally precedes the restore process.