[Info-vax] proper format for JPEG files

[Jan-Erik Soderholm]

Phillip Helbig---undress to reply wrote 2011-07-25 20:46:
> In article<+n8d2SpJNSm3 at eisner.encompasserve.org>,
> koehler at eisner.nospam.encompasserve.org (Bob Koehler) writes:
>
>> In article<j0f8q6$b1b$1 at online.de>, helbig at astro.multiCLOTHESvax.de (Phillip Helbig---undress to reply) writes:
>>> What is the "proper" format for JPEG files on VMS, in particular if they
>>> are served by a web server and displayed in a web browser?  I have some
>>> which are
>>>
>>>     Record format:      Fixed length 512 byte records
>>>     Record attributes:  None
>>>
>>> and some which are
>>>
>>>     Record format:      Stream_LF, maximum 0 bytes, longest 32767 bytes
>>>     Record attributes:  Carriage return carriage control
>>>
>>> and both work.
>>
>>     If they both work, then why should one be considered "proper" and not
>>     the other?
>
> Maybe both happen to work with the software combination I tested, but
> perhaps only one is supposed to work according to RFCs etc.
>

I do not think there is an "RFC" for OpenVMS file formats. :-)

The important thing is how the content is presented to the application
after beeing read from the file. Take the two files in you example.
They would propbably give the same "data" as long as the files are
opened using the correct record format/attribs. The I/O subsystem
should then strip any record delimiter and so on, and the web server
would see the same data (and of course the client also, the client
has no idea whatsoever about OpenVMS file attribs :-) ).

Any RFC's are probably about the format between the server and
the client, and that is well after any file I/O has been done.

The WEB server (OSU, WASD or whatever) hides the file I/O's from the
client/browser.

There will be problems if the actual file contents are not according
the the file attribs.

Jan-Erik.