A central facility is available to allocate device keys for those facilities that require them. This arrangement concentrates knowledge of the configuration of the system into one place. A subsystem (terminals or tapes) that requires device keys must provide a factory and a receptionist to the Device Allocator. Whenever a device is initialized by calling the DEVALOC key (p2,devalloc)) the Device Allocator calls the Device factory as follows:

The DEVDVR key is saved in a node associated with the device and subsequently "called" (actually forked with an entry key to the device allocator) when the device is initialized and each time the DEVDVR key returns as follows:

The Device Allocator maintains a node for each device allocated. The node is described as follows. This node is a red segment node and it is given to the DEVDVR as the fourth key in a FORK. The device driver will return to this key when it needs "service" such as a new device key.

DEVALOCF - the device allocator factory