cdash@boulder.Colorado.EDU (Charles Shub) (12/24/88)
At about 7:30 this evening, we successfully migrated an active demonstraton
program from a sun to a microvax using an enhanced V version 6.0 distributed
operating system. Happy holidays.
operationally, it is run of the mill active migration (ala theimer & cheriton's
"preemptible remote execution" paper of a few years ago) only the two machines
have different architectures.
essentially, we have an executable that has two text segments, one data
segment, and what we call a mapping segment. The process sends a message to the
migration server requesting the migration. The migration server then uses the
information in the mapping segment to remap the data (including pointers to
data and code) to the destination environment. The activation history (usually
a stack in most environments) must be similarly mapped. Obviously, a process
control block is also created on the destination machine. I'll be presenting a
paper on it at the Computer Science conference this february, and hope to have
something in shape to submit to sigops by their deadline.
Actually, we can migrate at about source statement granularity. Since the
process originates the migration, the migration always takes place when the
process is at a particular point in the migration request code. The sequence
leading up to that point can vary, so we need to be reasonably general about
mapping stacked contexts.
charlie shub cdash@boulder.Colorado.EDU -or- ..!{ncar|nbires}!boulder!cdash
or even cdash@colospgs (BITNET)
Prof. Charles M. Shub
Computer Science Department
University of Colorado at Colorado Springs
Colorado Springs, CO 80933-7150
(719) 593 - 3492