OTL and Infrastructure

To complete the full functionality of the OTL as described in the COBS architecture above requires extending the capabilities of some of the infrastructure on which COBS is based. In particular, at least the following extensions are known to be necessary:

PBIO

In the COBS architecture, PBIO is used to handle inter-OTL communication and for application parameter passing. In the latter use, the OTL passes uninterpreted PBIO parameter blocks between machines which are unpacked by higher layers. This requires the extension of PBIO to support a memory-to-memory model of encoding data values.

Cthreads

COBS uses the user-level threads in Cthreads as a vehicle for executing object invocations. Cthreads basic functionality is sufficient to support this role in most circumstances, but Cthreads is not currently not a preemptive threads package. In order to support fully asynchronous invocations, Cthreads must be extended with preemptive schedulers and signal handling capability.