From: Justin Voskuhl (justinv_at_microsoft.com)
Date: Mon Jan 12 2004 - 16:52:25 PST
In Programming Semantics for Multiprogrammed Computations the authors
describe the basic facilities in their system, the protection scheme it
implements and some basic definitions around processes. Then the
authors proceed to describe the functions available to processes around
parallel programming. These include the UNIX-style fork, an operation
to wait for a counter to be decremented, a way to quit a process,
locking (lock and unlock primitives.) The lock and unlock primitives
have a limit as to how long you can keep a lock, since the system can't
perform a context switch while you have a lock. There are ways to
create protected environments in which you can perform computations by
creating "sub spheres" in which you can restrict the capabilities the
computation can run with. There are primitives that are useful for
debugging sub-processes, such as examine, which lets you examine memory
in a subprocess. The naming scheme for segments is very interesting.
The names are rooted with principals (users) and proceed from there, so
each filename starts with a principal. However two principals can link
to the same directory, so sharing of files is permitted.
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