[HECnet] "IP protocols on DECnet'

[Thomas DeBellis]

At least for Tops-20, you have some sort of control on this because of 
two JSYi, SOUT% (write a string) and SOUTR% (write a string record).  
This difference was originally largely for magnetic tape for writing a 
'record' (my memory of what that meant is hazy).  It found its way into 
DECnet and almost into TCP/IP.

On DECnet you can block on records, using a SINR% to read a SOUTR%, 
which means you don't have to specify a length on read, which can speed 
certain things up. VIKING does this.  I think DAP might use it to mark 
end of stream.  The point is that a DECnet SINR% knows that a SOUTR% was 
used.  You can really win knowing this kind of meta data.

On TCP/IP SOUTR% sets PSH (push the existing data) which may get 
swallowed along the way, so it's not clear that a SINR% would wake up at 
the right point.  I can't remember if I did tests on this.

On 11/8/21 11:09 AM, Robert Armstrong wrote:
>> "when do you send the message".  That's actually a question with TCP as
> well...
>
>    You know about the Nagle algorithm, right?
>
> Bob
>
>
>
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