Re: Embedded languages based on early Ada (from "Re: Preferred OS, processor family for running embedded Ada?")

[Colin Paul Gloster <Colin_Paul_Gloster@ACM.org>]

In news:pan.2007.03.01.11.23.01.229462@linuxchip.demon.co.uk.uk.uk
timestamped Thu, 01 Mar 2007 11:22:32 GMT, "Dr. Adrian Wrigley"
<amtw@linuxchip.demon.co.uk.uk.uk> posted:
"On Wed, 28 Feb 2007 17:20:37 +0000, Colin Paul Gloster wrote:
...
> Dr. Adrian Wrigley wrote:
>
> "  Something like this
> might allow a "rebranding" of Ada (i.e. a new name, with full buzzword
> compliance), and would be ideal to address the "new" paradigm of
> multicore/multithreaded processor software, using the lightweight
> threading and parallelism absent from Ada as we know it. For those who
> know Occam, something like the 'PAR' and "SEQ" constructs are missing in
> Ada."
>
> I really fail to see the relevance of multiple processors to
> lightweight threading.

????

If you don't have multiple processors, lightweight threading is
less attractive than if you do?"

I was thinking that heavyweight processes -- whatever that term might mean,
maybe involving many processes, each of which is working on processing
intensive work without threads' unrestricted access to shared memory --
would be suitable for multiple processors.

"  Inmos/Occam/Transputer was founded
on the basis that lightweight threading was highly relevant to multiple
processors."

I reread a little of occam2 and transputers for this post. I do not
know much about them. I do not know.

"Ada has no means of saying "Do these bits concurrently, if you like,
because I don't care what the order of execution is"."

How do you interpret part 11 of Section 9: Tasks and Synchronization
of Ada 2005? (On
WWW.ADAIC.com/standards/05rm/html/RM-9.html#I3506
: "[..]

NOTES
11 1  Concurrent task execution may be implemented on multicomputers,
multiprocessors, or with interleaved execution on a single physical
processor. On the other hand, whenever an implementation can determine
that the required semantic effects can be achieved when parts of the
execution of a given task are performed by different physical
processors acting in parallel, it may choose to perform them in this way.

[..]")

Dr. Adrian Wrigley wrote:

"  And a compiler
can't work it out from the source.  If your CPU has loads of threads,
compiling code with "PAR" style language concurrency is rather useful
and easy.
--
Adrian"

Maybe I will read more about this some time.