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<p>DDP? I thought it was DUP-11.<br>
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<hr width="100%" size="2">On 1/15/21 4:21 PM, Peter Lothberg
wrote:
<div><br>
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Well, MRC was receiving "suggestions" from Stu Grossman on how
to do it, but<br>
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<div>if my memory does not fail me the block size was 312, due
to lack of buffer space<br data-mce-bogus="1">
</div>
<div>in the already crammed single section 512KW 2020. I'm
afraid my tape and disk-pack<br data-mce-bogus="1">
</div>
<div>are in Seattle. I knew it was not 576 as it had two
DUP-11's and using it for transit failed... <br
data-mce-bogus="1">
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<div><br data-mce-bogus="1">
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<div>Quiz, do you knew what a DDP is?<br data-mce-bogus="1">
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<div><br data-mce-bogus="1">
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<div>-P<br data-mce-bogus="1">
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<blockquote style="border-left:2px solid
#1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From:
</b>"tommytimesharing" <a class="moz-txt-link-rfc2396E" href="mailto:tommytimesharing@gmail.com"><tommytimesharing@gmail.com></a><br>
<b>To: </b>"hecnet" <a class="moz-txt-link-rfc2396E" href="mailto:hecnet@Update.UU.SE"><hecnet@Update.UU.SE></a><br>
<b>Sent: </b>Friday, January 15, 2021 3:59:25 PM<br>
<b>Subject: </b>Re: [HECnet] Thousands of DECnet errors on
Tops-20<br>
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<p>Was this maybe that magical version 5 of Tops-20 that MRC
put together for the 2020? I sure would love to see the
sources for that! I'm not sure if this is relevant, but
the following macro in D36COM is of interest:<br>
</p>
<blockquote><font size="+1"><tt>DEFINE KNMMCS,<</tt><tt><br>
</tt><tt>; Symbol,Name,Cost, Maximum
receive block size</tt><tt><br>
</tt><tt> KNMMAC LD.TST,TST, 1,
0 ;TST DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.DTE,DTE, 3,
<^D576> ;DTE DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.KDP,KDP, 4,
<^D576> ;KDP DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.DDP,DDP, 5,
<^D576> ;DDP DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.CIP,CI, 2,
<^D576> ;CI DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.NI ,NI, 1,
<^D1504-%RTEHS> ;NI DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.DMR,DMR, 2,
<^D576> ;DMR DEVICE</tt><tt><br>
</tt><tt>>;END OF KNMMCS</tt></font><br>
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<p>What can be seen is that the maximum block size is 576 in
<u>all</u> cases except the NI, which is 1476 bytes. I
don't know if any of these devices are relevant to the
2020; one assumes that the DTE, CI and NI are not.<br>
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<hr width="100%" size="2">On 1/12/21 3:29 PM, Peter
Lothberg wrote:<br>
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The DECnet segment size has to be the same "network
wide".<br>
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<div><br>
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<div>If I remember right DECnet looks at the two end
nodes and uses the smalles segment size, <br>
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<div>so if there is any transit node in the path with a
small segment size things will not work as <br>
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<div>it will drop packets bigger than it''s size.<br>
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<div><br>
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<div>The only SW/HW combination I knew of that has other
than 576 is MRC/Stu DECnet for <br>
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<div>Tops20 4.x on DEC2020.<br>
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<div><br>
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<div>-P<br>
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