Machine Room Functions
It seems that warnings of shutdowns must be integrated to some extent with the application. Newer work stations require specialized support in order to get a message to the operator at that station. The nature of the application may require special considerations with regard to shutdown. There may be other systems outside the computer center (not just the "users") that need to be warned.
For each base perceived by the kernel:
what DASD addresses are currently "mounted" in the Gnosis kernel terminology.
at what addresses the kernel will recognize disk drives,
what Tymnet bases are in what states,
at what addresses the kernel will talk to Tymnet bases.
How many circuits are thru each base and to some as yet unspecified degree, who they are.
Messages to users who are willing to receive.
There also needs to be a system status bulletin board available upon which to post downtime schedules and such.
Normally this is done so as to provide safety against failure of disk drives. In this case we are likely to place the redundant storage on different controllers and better different channels.
Each time a page or nodepot is written into this redundant it is quickly written into both. Upon reading either copy is used depending on busyness of the hardware.
Upon reintroduction of the repared drive we initiate a resynchronizing process to return to the redundant state.
In this scheme the exposure is limited to the likelihood of a disk failure in the 20 to 40 minutes required to regenerate the new disk.