Section 12.8: Isolated Scopes

["Oliver Kopp" <oliver.kopp@iaas.uni-stuttgart.de>]

Section 12.8 reads:

--cut--
The isolated attribute of a scope, when set to "yes", provides control of
concurrent access to shared resources:
--end--

But the explanation reads:

--cut--
Suppose two concurrent isolated scopes, S1 and S2, access a common set of
variables and partner links (external to them) for read or write operations.
The semantics of isolated scopes ensure that the results would be NO
DIFFERENT if all conflicting activities (read/write and write/write
activities) on all shared variables and partner links were conceptually
reordered so that either all such activities within S1 are completed before
any in S2 or vice versa.
--end--

Regard the following example.

Global variable x

Scope S1: sets x to 1
Scope S2: sets x to 2

S1 runs in parallel to S2.

Then the result is not independent from the execution order of S1 and S2.


Is there a mistake in the text?

Should it be something like following?

--cut--
The semantics of isolated scopes ensure that all conflicting activities
(read/write and write/write activities) are not executed in parallel. The
order of execution is non-deterministic and thus the result is
non-deterministic, too.
--end--


Regards,

Oliver Kopp


--
University of Stuttgart
Institute of Architecture of Application Systems (IAAS)
Universitätsstraße 38 - 70569 Stuttgart
+49 711 7816 - 483
http://www.iaas.uni-stuttgart.de