Re: How proprietary is the "COBOL file system"



"Richard" <riplin@xxxxxxxxxxxx> wrote in message
news:1191179230.655139.4510@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Sep 30, 6:20 pm, Robert <n...@xxxxxx> wrote:
On Sun, 30 Sep 2007 17:18:10 +1300, "Pete Dashwood"
<dashw...@xxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:

Can anyone tell me if MicroFocus COBOL can read Fujitsu ISAM files, and
vice
versa? What about Realia?

Obviously, at the source code level (SELECT and FD/01) the code is
compatible, but what about object level?

Is there a single PC ISAM system, or do all the COBOL vendors have their
own
proprietary indexed system which is delivered with their COBOL compiler?

I know what I THINK the answer is, but would be gald to hear any other
facts/opinions about this.

All three are proprietary.

On Windows, Micro Focus uses its own External File System (extfs). On
Unix, extfs is
available but the default is C-ISAM, which is owned by Informix, which is
owned by IBM.

You seem to miss the point about 'extfs', it means that _ALL_ formats
are external, ie not built into the base runtime system. C-ISAM is
external, C2 is external, BTrieve is external, your own homegrown is
external. Usually the one that is used is C-ISAM on Unix and C2 on DOS/
Windows and both of these are in 'extfs.dll' (or similar).

There has been bad blood between the companies in recent years. MF refers
support
questions to Informix. They want you to use extfs.

I don't know about Fujitsu. I assume it's proprietary.

Fujitsu uses mechanisms derived from their mainframe range to give
compressed data (RLL) and indexes in the data file.

Realia is very proprietary. Marc Sokol said they spent more time
developing the file
systsem than the compiler. In the MS-DOS era, it was blindingly fast.

The most likely place to find interoperability is in ODBC drivers.

This is not useful if the programs do READ/WRITE.

Thanks for this, Richard. Very interesting.

I'm curious about your last statement.

I have only ever used ODBC to access RDBs, although I understand there are
some ODBC drivers available now to access indexed files also.

Why would writing with ODBC be a problem? Can you elaborate? I've never had
trouble reading and writing Databases.

Cheers,

Pete.
--
"I used to write COBOL...now I can do anything."



.