[Info-vax] wrong file format

[Arne Vajhøj]

On 1/1/2021 11:52 AM, Dirk Munk wrote:
> Bill Gunshannon wrote:
>> On 1/1/21 10:46 AM, Dirk Munk wrote:
>>> Bill Gunshannon wrote:
>>>> On 12/31/20 3:58 PM, Dirk Munk wrote:
>>>>> like indexed files. What will that application do with those files? 
>>>>> RMS will tell you the structure of the file, you don't have to 
>>>>> guess it.
>>>>
>>>> I use GnuCOBOL.  sequential files show up as "ASCII text: as does the
>>>> COBOL Source File.  Indexed report as "Berkeley DB" as that was the
>>>> option I chose for indexed files when I built GnuCOBOL.  Other COBOL
>>>> compiler (like MicroFocus) may differ. Of course, the executable shows
>>>> up as "ELF 64-bit LSB shared object".  If I wanted to put in the
>>>> effort I could probably get it to identify the source as COBOL source
>>>> but I  see no reason to bother.
>>>>
>>>
>>> Cobol source files are always text files of course. But again, with 
>>> VMS all the file types are offered by RMS, and can be used by any 
>>> language or even DCL.
>>
>> And, as I stated above the exact same is true of Unix and OS-9 and
>> RT-11 and Windows and probably every other OS.
> 
> No, Unix does not offer indexed sequential files etc. as standardized 
> part of the operating system. They can be added as part of a compiler, 
> like Cobol, but then those files can only be used by applications 
> written with that compiler, unless the same filesystem is used by 
> another compiler.

File system does not matter - from the file system perspective
then ISAM files are also just a stream of bytes on *nix.

But yes different compilers use different ISAM libraries. So
to access files using a different compiler, then either that
compiler must use the same library *or* the program must
use the library API explicit.

> It seems that Windows does have more file types as part of the OS, but 
> that feature is very well hidden.

What are you referring to?

Arne