[Info-vax] RMS intro

[Arne Vajhøj]

On 1/2/2024 8:39 AM, Simon Clubley wrote:
> On 2023-12-30, Arne Vajhøj <arne at vajhoej.dk> wrote:
>> So I took:
>> * what everybody knows about RMS
>> * relative file and direct access fixed length file examples
>>     I recently posted
>> * the index-sequential file examples I have used numerous times before
>> * some file read and file creation test code I did a few years ago
>> and baked it into:
>>
>> https://www.vajhoej.dk/arne/articles/rms.html
> 
> Some feedback:

Thanks. Apperciated.

> About your VFC comments: what does Fortran carriage control use on VMS ?
> You say there is no use for VFC, but then you go on to say Fortran uses
> VFC for carriage control.

DCL use record format VFC with carriage control PRN .

Fortran default use record format VAR with carriage control FTN.

I hope that is what I communicate:

<quote>
Nobody seems to see a purpose with VFC record format. But DCL create 
files in VFC record format, so it is used.
...
  Fortran carriage control use the first column in file for control. A 
space ' ' in first column means ordinary new line. A one '1' in first 
column means new page. This is a very old Fortran convention. And 
usually it is only files generated by Fortran programs that use Fortran 
carriage control, but VMS and RMS support sit.

Print carriage control use the content of the control information for 
VFC files to manage output.
</quote>

(but I just noted that I can't count to 3)

> You may wish to make explicit what the maximum record size is with RMS.

Yes. That is important. It may not have been a severe limitation
in 1977, but it sure is today.

And I would need to mention Fortran segmented files.

> Do you want to discuss the history of ISAM files with their different
> prolog versions ?

I want to but I can't.

:-)

I don't have the knowledge.

> You may wish to make it clear that RMS is a part of VMS in that it is
> within VMS itself and not just some user-mode library linked in to each
> user program.

I should probably mention EXEC mode

> You may wish to make the byte ordering explicit by giving offsets to
> each field. IOW, make it clear that the control data is at the start
> of each record and that fields are in little-endian and not big-endian
> format. This matters because different operating systems have both
> different documentation and endian conventions.

Yes.

Not as big a problem today as 25 years ago. But still relevant.

Arne