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<p>At least for Tops-20, you have some sort of control on this
because of two <font size="4"><tt>JSYi</tt></font>, <font
size="4"><tt>SOUT%</tt></font> (write a string) and <font
size="4"><tt>SOUTR%</tt></font> (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.</p>
<p>On DECnet you can block on records, using a <font size="4"><tt>SINR%</tt></font>
to read a <font size="4"><tt>SOUTR%</tt></font>, which means you
don't have to specify a length on read, which can speed certain
things up. <font size="4"><tt>VIKING</tt></font> does this. I
think DAP might use it to mark end of stream. The point is that a
DECnet <font size="4"><tt>SINR%</tt></font> knows that a <font
size="4"><tt>SOUTR%</tt></font> was used. You can really win
knowing this kind of meta data.<br>
</p>
<p>On TCP/IP <font size="4"><tt>SOUTR%</tt></font> sets <font
size="4"><tt>PSH</tt></font> (push the existing data) which may
get swallowed along the way, so it's not clear that a <font
size="4"><tt>SINR%</tt></font> would wake up at the right
point. I can't remember if I did tests on this.<br>
</p>
<div class="moz-cite-prefix">On 11/8/21 11:09 AM, Robert Armstrong
wrote:<br>
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cite="mid:009e01d7d4bb$010c5fc0$03251f40$@com">
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<pre class="moz-quote-pre" wrap="">"when do you send the message". That's actually a question with TCP as
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<pre class="moz-quote-pre" wrap="">well...
You know about the Nagle algorithm, right?
Bob
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