I'm trying to read your message alongside the DAP 5.6.0 spec and getting absolutely nowhere.  None of the terms you mention are in the DAP spec.  Can you describe what you're seeing in terms of the spec?  And/or include a (binary format) tcpdump protocol capture?

paul

On Nov 29, 2022, at 12:41 PM, Thomas DeBellis <tommytimesharing@gmail.com> wrote:

I fixed the bit definition for Not Last Message of Segmented Message from bit 4 to 6 as per DAP V5.6 and properly defined bit 4 as the Reserved field.  In other words, I am following Tops-10, which I believe to have the correct definitions.  Then I finished the flag breakout logic and tested again some systems.  The MIM:: result is of note, viz.:

[Parsing Name message]
[Parsing Attributes message]
[Allocated Receive buffer (Words=531. Len=2086.)]
[Trimmed 381. words from receive buffer]
[Received Date/time Attributes message (Flg=*RESV*,SYSPEC UFlg=1000 Cnt=560.)]
[Parsing Date/time Attributes message]
[Parsing File Protection Attributes message]
[Parsing Name message]
TEST.DIS;1;P775656               2 2560(8)    18-Nov-2013 01:18:27

So what's up with *RESV*?  Is (reserved) bit 4 being used for something new (I.E., post DAP 5.6) now?  If so, what?  The UFlg is an octal field for bits that I don't know about.  In this case, MIM:: is sending bit 9 high, which the PDP-10 (which is the opposite endian) sees as bit 26.  What's that?

Just wondering if I'm seeing what I'm seeing here...

On 11/27/22 12:34 AM, Thomas DeBellis wrote:

Whoops, I mistyped the PDP-10 bit definition for bit six; it's 1B29 and not 1B28.  Sigh...


DAP
Bit		Bit MeaningPDP-10
Bit		Tops-20
DAP Symbol
0Stream Identification Field Present1B35HD$SID
1Length Field Present1B34HD$LEN
2Extended Length Field Present1B33HD$LN2
3Bit Count Field Present1B32HD$BCT
4Reserved1B31HD$SEG
5System Specific Field Present1B30 
6Not last message of segmented message1B29 

I looked the Tops-10 DAP flags definitions (in SWIL.MAC); it looks like Tops-10 has it right and Tops-20 has it wrong, viz:


DAP
Bit		Bit MeaningPDP-10
Bit		Tops-20
DAP Symbol
0Stream ID field present1B35DF$SID
1LENGTH field present1B34DF$HLN
2LEN256 field present1B33DF$HL2
3BITCNT field present1B32DF$BCT
4Reserved1B31DF$XX1
5SYSPEC field present1B30DF$SHX
6More data coming1B29DF$MOR

Johnny, can you send me the RSX DAP flag definitions when you get a minute?

On 11/26/22 11:58 PM, Thomas DeBellis wrote: 

I was writing a routine to break out DAP flag bits to aid debugging when I noticed a possible discrepancy between DAP V5.6 and Tops-20, viz:

DAP
Bit		Bit MeaningPDP-10
Bit		Tops-20
DAP Symbol
0Stream Identification Field Present1B35HD$SID
1Length Field Present1B34HD$LEN
2Extended Length Field Present1B33HD$LN2
3Bit Count Field Present1B32HD$BCT
4Reserved1B31HD$SEG
5System Specific Field Present1B30 
6Not last message of segmented message1B28 

DAP V5.6 reserves bit 4 and defines bit 6 to flag that a segmented message is being sent and that this is not the last message.  In other words, that there will be another message.  Tops-20 is using bit 4 for this purpose and by rights it would appear that it should be using bit 6.

I will go see if I can't scare up what Tops-10 is doing, but I was wondering if anyone knew what other OS's are doing.



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