TechTalk: Allocating Devices to Subsystems

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By default, the subsystem QINTER allocates all devices by workstation type?not by name. The purpose of this is to capture and allocate all devices regardless of the naming convention used. As you go about configuring your system, you may wish to allocate workstations by subsystems other than QINTER. The following information can be found in the OS/400 Work Management V3R1 (SC41-3306, CD-ROM QBKLAG00):

? When a subsystem starts, it attempts to allocate all workstation devices in the subsystem description. There is no hierarchy regarding device names versus device types.

? If the device is varied off, the subsystem cannot allocate it. The system arbiter (QSYSARB) holds a lock on all devices that are varied off.

? If the device is varied on and is not allocated by another subsystem, then the subsystem can allocate it and display the sign-on display.

? If the device is allocated by another subsystem and is at the sign-on display (i.e., no active job), the second subsystem can allocate the device from the first subsystem.

? If the device is varied off and all subsystems have started before you vary on the device, and if more than one subsystem could potentially allocate the device, it is unpredictable which subsystem will actually allocate it.

To avoid the situation of unpredictability, you can do one of the following things:

? Do not use workstation type entries in any subsystem?use only workstation name entries. This means removing the

workstation type entries from the IBM-supplied subsystem descriptions. Use the Remove Workstation Entry (RMVWSE) command. You can enter workstation name entries using generic prefixes (e.g., DSP*).

? Vary the workstation on when the system is started by specifying ONLINE(*YES) in the device description for the workstation. The subsystem that allocates the device is determined by the order in which the subsystems start.

? You can add workstation entries to a subsystem description, which causes the subsystem to allocate the device or not allocate the device.

To include the device, use this command:

 ADDWSE SBSD(xxx/sbsd) + WRKSTN(dev) AT(*SIGNON) 

To exclude the device, use this command:

 ADDWSE SBSD(xxx/sbsd) + WRKSTN(dev) AT(*ENTER) 

The AT(*ENTER) parameter keeps the subsystem from allocating the device at subsystem startup, but allows you to use the Transfer Job (TRFJOB) command to transfer the job after subsystem startup.

? Steve Bisel

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