[Simh] OpenVMS time conversion routines

[Johnny Billquist]

If you are writing in C, then even if the machine is 32 bits, the C 
language will normally give you a 64-bit integer data type, so you 
should be able to do this really easily, and portable. The biggest 
question when it comes to portability would be byte ordering...

In fairly modern C:
int64_t

in older:
long long

   Johnny

On 2020-05-07 07:28, Baker, Lawrence M wrote:
> Does anyone know of any portable OpenVMS 64-bit time conversion routines 
> written in C?  I.e., that do not depend on 64-bit data types so they run 
> on 32-bit machines?  Maybe in the SIMH GitHub?  Out there in the Interland?
> 
> I am writing a simtools converter that combines on-disk OpenVMS Backup 
> save sets into a SIMH .tap image of an OpenVMS Backup ANSI tape volume. 
>   I want to use the date the backup was done from the Backup save set 
> header for the ANSI HDR1 Creation Date.
> 
> You might ask why?  Lately I have had to restore Backup save sets stored 
> on our NFS file server to SIMH VAXes over a DECnet/DAP-to-NFS gateway I 
> built a number of years ago.  (I wrote to this group about it in a 
> thread about RSTS/E 10.1-L and Paper tape on January 6, 2016.)  It takes 
> about 2 days to restore an ~8GB disk image backup from the NFS server, 
> though the gateway running on an SheevaPlug ARM SoC, to the SIMH VAX 
> running on my desktop iMac.  I am working from home at the moment, of 
> course.  I have become good friends with GNU screen because of SSH 
> inactivity disconnects and VPN failures.  When I tried to restore a 75GB 
> disk, expecting it to take 10-14 days, our "friendly" IT security 
> monsters rebooted my iMac on me after 4 days.  Grrr.  I want to try 
> breaking the NFS file server transfer step from the SIMH VAX restore 
> operation.  OpenVMS is not so easy as RSX was to read /FOREIGN disk 
> drives as files.  I could not figure out a way to just MOUNT a Backup 
> save set as a SIMH disk image and get that to work.  I was able to use 
> Mark's tar2mt converter and, using the proper OpenVMS MOUNT /RECORDSIZE 
> and /BLOCKSIZE qualfiers, was able to read a Backup save set from an 
> unlabeled tape image.  Labeled tapes are easier to use then unlabeled 
> tapes, since the file names and file formats are on the tape with the 
> file data.  I know how to write ANSI tape labels, so I have taken it 
> upon myself as a challenge to write a converter.  I think this is the 
> last piece I need for what I want it to do.  I'll certainly announce it 
> when it is done.
> 
> Thank you in advance for your help.
> 
> Larry Baker
> 
> US Geological Survey
> 
> 650-329-5608
> 
> baker at usgs.gov
> 
> 
> 
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-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol