[Info-vax] wrong file format

Stephen Hoffman seaohveh at hoffmanlabs.invalid
Fri Jan 1 13:21:58 EST 2021


On 2021-01-01 16:52:50 +0000, Dirk Munk said:

> 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.

Donno. The Unix distro I use includes database support. And most apps 
will use that or will use another readily-available database, typically 
one supported by the language(s) involved.  And given typical COBOL app 
packaging, should the COBOL app be using something not integrated with 
the system, it's almost certainly been loaded using the local package 
manager, and it's then available for other apps. Locally, poking inside 
bundled apps is a little more work, but most know databases can be very 
quickly identified using file magic; with one command, if the database 
used is not already apparent from the database filename used.

But again, directly accessing the database underneath some unrelated 
app is not something most folks are even doing, outside of reverse 
engineering that particular app.

And reverse-engineering some unrelated app's RMS indexed file is Less 
Than Fun. RMS might be consistent, but reverse-engineering RMS database 
record formats is not.

As I'm presently working on something similar, reverse-engineering one 
of the more common sorts of macOS databases—on OpenVMS—is easier than 
reversing native RMS file formats on OpenVMS, too.

So... RMS database integration was a wonderful thing in the 1980s and 
1990s, integrated databases are nice, but it's less of a differentiator 
in this era given the prevalence of databases.

For those few that do need to reverse-engineer a data store, I'd 
certainly prolly prefer a data store other than RMS due to the 
difficulties inherent in RMS database record-level reversing. And if I 
do have the record definitions from the COBOL or other code, accessing 
that data store in any of the common databases is little different from 
accessing RMS databases.

And yes, I would prefer to see SQLite integrated into OpenVMS, or 
MariaDB, or—with SSIO resolved—PostgreSQL. But installing some database 
onto a Unix system is not an intractable hurdle. It's usually one or 
two package manager commands, if not already loaded.


-- 
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