[HECnet] DAP

[Thomas DeBellis]

Yes, that is the version of DAP that I have.  Actually my DAP is a 
little later in that a Y2K problem was fixed.  This was a non-DEC 
change, so I don't know if it ever made it into sources.

That little snippet of code below is /quite/ interesting. It would 
appear that the VMS DAP will not allow a rename unless the partner 
claims DAP V7.   That's counter-intuitive, because what is supposed to 
happen is that mutually supported capabilities are derived from the 
config message.  Since Tops-20 does not report SY$REN it will not be 
reported and a rename will thus (supposedly) never be requested.

So even if I implement it, VMS won't use it unless I decide to lie about 
my DAP version.  That's not the worst thing in the world, there were a 
number work-arounds in Tops-20 to address certain limitations of the DAP 
implementation of the time.  One assumes these would have been fixed.

What is the difference in practice between functions 7 (SUBMIT) and 8 
(EXECUTE)?  In both cases, Tops-20 submits the file as a Batch job to 
Galaxy, this being the only way to construct the proper user context.

On 12/10/19 3:33 AM, G. wrote:
> On Mon, 9 Dec 2019 16:38:30 -0500, Thomas DeBellis wrote:
>
>>   1. My own version of FAL appears quite dated; it only has edits to
>>      Tops-20 V6.1 (1985), whereas the last monitor distributions were in
>>      the 7 series.
>>        * Does anybody have any source files later than that for Tops-20?
> As far as I know, the latest DAPLIB.MAC is the following, and the same
> directory contains a full set of updated DECnet-20 source files, although
> you probably already know/have them:
>
> http://pdp-10.trailing-edge.com/CFS_TSU04_19910205_1of1/02/update/decsrc/daplib.mac.html
>
>>   3. The implementing DAP module (DAPLIB) appears even older, apparently
>>      dating to V6.0, 1981 time-frame (which seems incorrect).  It
>>      supports DAP 5.6, for which I have the specifications.
>>        * It does /not/ support $RENAME (ACCFUNC 3), which I found
>>          remarkable.  Is $RENAME supported on all other platforms?
>>        * I note that ACCFUNC 5 is reserved.  Is this used now?
>>        * Is ACCFUNC 0 used?  For what?
>>        * Is any ACCFUNC later than 8 defined?  What is the first free one?
> According to some VMS V7.2 DECnet source files I have access to, the
> following are the only defined access functions available. Number 5 was
> still defined as reserved:
>
>    ASSUME  DAP$K_OPEN EQ 1
>    ASSUME  DAP$K_CREATE EQ 2
>    ASSUME  DAP$K_RENAME EQ 3
>    ASSUME  DAP$K_ERASE EQ 4
>    ASSUME  DAP$K_DIR_LIST EQ 6
>    ASSUME  DAP$K_SUBMIT EQ 7
>    ASSUME  DAP$K_EXECUTE EQ 8
>
>  From what I can understand, DAP V6.0 introduced some minor tweaks, e.g.
> backup date and time in the DAP date and time message. Apparently, DAP V7.0
> introduced some more acknowledge messages, stream file support, and above
> all (at last) the rename function:
>
>    ;++
>    ; This routine performs the DAP RENAME file function.
>    ;--
>
>    FAL$RENAME::                            ; Entry point
>            BBS     #DAP$V_GEQ_V70,(R9),10$ ; Exit if partner does not support
>            BRW     FAL$UNS_ACCFUNC         ;  DAP V7.0
>            .
>            .
>            .
>
> Hope this helps, :)
> G.
>
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