How to send a variant protocol over a link?

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3 total messages Started by Stefan Friedli Thu, 17 Mar 1988 13:08

#1995

Author: Stefan Friedli
Date: Thu, 17 Mar 1988 13:08

20 lines
1240 bytes

I hope someone can help with the following problem:

For a program I currently develop, it would be a nice and elegant
way to have a variant protocol on a physical link. As this is
not supported by the configuring language (only CHAN OF ANY is
allowed for links), I looked for (and found) a solution: declare
the links as CHAN OF ANY, pass it as an actual parameter to some
procedure that has as the corresponding formal parameter a channel
of a variant protocol.

Problem: This works fine (and does what it's supposed to do!!!)...
on the compiler in d700C. The new compiler in d700D rejects this
way of parameter passing and according to a note of INMOS (Writing
occam programs to minimise future changes, June 24, 1987, paragraph
2: Protocols), this restriction will be kept in future releases.

Anyone out there to help?

Thanks. Stef.

Re: How to send a variant protocol over a link?

#2022

Author: S Tett
Date: Sat, 19 Mar 1988 17:26

27 lines
1447 bytes

In article <8803171831.AA04508@tcgould.TN.CORNELL.EDU> U06A@CBEBDA3T.BITNET (Stefan Friedli) writes:
>>
>I hope someone can help with the following problem:
>
>For a program I currently develop, it would be a nice and elegant
>way to have a variant protocol on a physical link. As this is
>not supported by the configuring language (only CHAN OF ANY is
>allowed for links), I looked for (and found) a solution: declare
>the links as CHAN OF ANY, pass it as an actual parameter to some
>procedure that has as the corresponding formal parameter a channel
>of a variant protocol.

The way to solve this little problem without recourse to hacking is
to declare a buffer.(I'll give an example for an output link)

PROC buffer(CHAN OF PROTOCOL ..... in,CHAN OF ANY out)
-- out is the output CHAN to the hard link
  INT var1,var2,var3......:
  WHILE TRUE
    SEQ
      in ? var1;var2;var3 -- assuming protocol is INT;INT;INT
      out ! var1;var2;var3
:

Simon

Meteorology Dept/Physics Dept Concurrent "Super"-Computer User

Re: How to send a variant protocol over a link?

#2037

Author: Mark Hughes
Date: Tue, 29 Mar 1988 08:44

18 lines
1362 bytes

From article <8803171831.AA04508@tcgould.TN.CORNELL.EDU>, by U06A@CBEBDA3T.BITNET (Stefan Friedli):
> 
> For a program I currently develop, it would be a nice and elegant
> way to have a variant protocol on a physical link. As this is

I can't try this and feel it sounds too simple, but...

it should be possible to instert a dummy process between the physical link
and your "variant protocal channel". This process would have two paramters,
one a channel supporting your variant protocol and the other a CHAN OF ANY,
"placed at" the physical link. The process's sole function is to relay
information between the variant protocal channel and the link. It's a bodge,
but simple enough not to be too unpleasant. I hope it works!
-- 
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