Opening c isam files?

Question

I am trying to find a way to access a database of some management software which uses some kind of raw isam files to store the data. The data folder compromises of of .idx and .fs5 files, I cannot find any evidence of this being a informix type as mentioned in another question here on stackoverflow.

Does anyone have any kind of solution to creating some kind of bridge to the database? I have had no luck finding an open source odbc to c-isam driver, is anyone aware of something that could possibly help here?

Answer 1

FS is possibly a Flagship file, a product that uses the same format as Ashton Tate's dBase III.

This link may help:

Open your *.FS5 file by any Hex-Editor. If the first byte is (hex) 03 or 83, it is a dBaseIII+ compatible database, fully supported by FlagShip. If the 1st byte is 04, 05, 13, 23, 33, 93, B3 it is a database with FlagShip extensions. If the first byte of *.idx is (hex) 52, it is FlagShip index. See additional details on http://www.fship.com/dbfspecs.txt. If above apply, go to http://www.fship.com/eval.html for free test version of FlagShip.

If it is a Flagship file, the documentation at the link given above states that the file format for database files (but not indexes apparently) is fully compatible with dBase III so you may be able to find software (dBase, Clipper, FoxPro, Excel et al) that can extract the data if not the index info.

They also handily detail the file format in the LNG section of their docs but dBase III format is well known so you may be able to get more information elsewhere, such as here.

If it turns out to not be a Flagship/dBase file, you'll have to do some more research. The only other thing the internet suggests is that it may be a Flight Simulator file, which seems unlikely :-)

You could try running a strings command on the files to see if any vendor-type information shows up.

Failing that, it may be that the best solution is to contact the vendor of the management software to see if they'll part with the information. Social engineering like that may provide a quicker solution than trying to reverse engineer the format.

Answer 2

I don't know about .fs5 files, but a classic C-ISAM file is almost the same as a flat file.

The only difference is that deleted records are replaced with null bytes (hex 00). So if you write a program to remove the null bytes, you should be able to read it as a flat file.

Answer 3

IBM has a C-ISAM bridge for their Online RDBMS engine that re-hosts the C-ISAM files as tables in the RDBMS. You can then use SQL to access the data.