On Aug 26, 2:14 pm, Chico Che wrote:
> I have an OpenVMS Alpah System that has RMS data files. I have a .dat file
> that if edited you can see clearly fixed length fields in there. The
> question I have where would I find the files that would tell me what field
> is what and the length of that field. So I can know the data structure of
> the dat file.
>
> TIA

Chico,

This post does not mention if the files are sequential or indexed. RMS
files do not contain record descriptions internally. The best chance
of obtaining that information is in the programs that actually create
and maintain the files. Often this information is contained in self-
contained files that are included when the programs are compiled, but
this is not always the case.

Information about the layout of the key fields in indexed RMS files is
contained in the file's preamble, and can be displayed using the
ANALYZE/RMS command.

- Bob Gezelter, http://www.rlgsc.com

Bob Gezelter wrote in news:67f8fafd-9a50-4372-9661-
0766d8f24e51@d1g2000hsg.googlegroups.com:

> sequential or indexed

Thanks a lot for your help, the ANALYZE/RMS does give you info I needed.
One question, I get fields that fit but at end it seems there is extra data
that seems it's like comment or addl desc but no point in the analyze
command that gives me this. Any ideas?

Chico Che wrote:
> I have an OpenVMS Alpah System that has RMS data files. I have a .dat file
> that if edited you can see clearly fixed length fields in there. The
> question I have where would I find the files that would tell me what field
> is what

The file that might have that information is the source code for the
program(s) that write and read the file. Another possibility would be
written documentation for the program.

and the length of that field. So I can know the data structure of
> the dat file.

Again, see the source code. If you have no access to the source code,
there is very little you can do

Chico Che wrote:
> I have an OpenVMS Alpah System that has RMS data files. I have a .dat file

ANA/RMS/FDL/OUTPUT=myfile.fdl will give you a full file
definition for .

This will include the record format, and if the record format is fixed,
its record length. It will also give you definition of each key in the
file (position, length, and possibly a field name).

It will not give you full field definitions for fields that are not key
fields. It will not give you the valid values for each field.

So the FDL gives you a start, but you have to reverse engineer the rest,
or if you have the original sources, look at them where you will find
record layouts.

On Aug 26, 4:23 pm, Chico Che wrote:
> Bob Gezelter wrote in news:67f8fafd-9a50-4372-9661-
> 0766d8f24...@d1g2000hsg.googlegroups.com:
>
> > sequential or indexed
>
> Thanks a lot for your help, the ANALYZE/RMS does give you info I needed.
> One question, I get fields that fit but at end it seems there is extra data
> that seems it's like comment or addl desc but no point in the analyze
> command that gives me this. Any ideas?

Chico,

ANALYZE/RMS will report information about the keyed fields, namely the
fields that are accessible using indexed operations. ANALYZE/RMS
cannot display any information about the non-key fields in the file,
as that information is not present in the file.

As Richard has mentioned in his response, that information must be
retrieved from the source code or similar source.

- Bob Gezelter, http://www.rlgsc.com

In article , Chico Che writes:
> I have an OpenVMS Alpah System that has RMS data files. I have a .dat file
> that if edited you can see clearly fixed length fields in there. The
> question I have where would I find the files that would tell me what field
> is what and the length of that field. So I can know the data structure of
> the dat file.

Nit: almost all files on a VMS system are RMS files.

You probably need to look at the source program that wrote it. If RMS
is tracking it as fixed length records, then divisions within the
record are unknown to the OS. If RMS is tracking it as a
keyed-indexed file then only the key field(s) are known to the OS.

DIRECTORY/FULL will show you how RMS is tracking it. ANALYZE/RMS/FDL
will write an .FDL file describing the known details, which is
usefull if it is keyed.

Chico Che wrote:
>
> I have an OpenVMS Alpah System that has RMS data files. I have a .dat file
> that if edited you can see clearly fixed length fields in there. The
> question I have where would I find the files that would tell me what field
> is what and the length of that field. So I can know the data structure of
> the dat file.

As others have pointed out, the actual data format in the files will be
defined by the programs which use them. So, you will likely need to
examine some source code.

That said, if a product called Datatrieve is installed, there may
already by definitions for those files in the Datatrieve dictionary.

See if you have a "DATA[TRIEVE]" verb (can be shortened to DATA,
obviously), or look at DIR SYS$SYSTEMTR* and see if anything gets
listed. That will tell you if Datatrieve is there. If it is, try to RUN
it.

The program development environment, if any, on the machine may include
the old CDD product (Common Data Dictionary) which provides a common
data format repository for programming language compilers as well as for
Datatrieve. I believe the program to seek is DMU ( DIR SYS$SYSTEMMU*),
but that may be wrong. It's been a while since I dealt with that one. If
you find it, poke around in its on-line HELP and see if you can figure
out how it works.

Hope this helps...

D.J.D.