[Info-vax] RMS intro

[Arne Vajhøj]

On 1/2/2024 9:12 AM, Arne Vajhøj wrote:
> 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.

>> 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.

>> 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.

Updated:
* add Groovy examples
* add examples using byte offset seek to mimic access by
   record number to fixed length records
* add a lot about record size
* add note about RMS being exec mode and lengths being little endian

Still:

https://www.vajhoej.dk/arne/articles/rms.html

Arne