descriptor" option of the
file block
the
a tag slot is available. If it is, a tag is built, using information in
the
inactive files
slot is not available, the file is placed in a pending status and the
link table entry count of pending files
one. Pending files are added to the inactive file queues as slots
become available.
(TAGACIN). The file's tag and first spool buffer are then passed to the
line driver task for transmission. Any additional spool buffers for
that file are directly obtained by the line driver task.
Task-to-Task Communication
GIVE/TAKE requests are issued by lower-priority tasks, such as line
drivers, to request a service from a higher-priority task, such as a
supervisor service routine. The requesting task builds a request table
containing the name of the task that is to perform the service, along
with pointers to a request buffer containing the data required for the
service. If appropriate, a pointer to a response buffer is also
supplied. This information is passed to the
chains it on the
execution of a particular service
the service that was just completed, passes any response data back to
the requestor via the response buffer, locates the next
that service task, and passes the corresponding request table data to
the service task for execution.
ALERT requests are issued by high-priority tasks for services to be
performed by a lower-priority task. These requests are not queued; the
lower-priority task is executed as soon as it is received. ALERT
requests are handled by the
The primary command processor in
centrol task.
read started by the
from the
command element, provided by an active line driver task.
Part 4. Remote