DIBOL
I recently worked at a system integration company that needed to extract data from a customer's legacy system.
Several companies before had tried and failed.
We got some sample data and these 'strange' schema definitions. No access to the source code.
Fortunately I worked at DEC in the 1980's and recognised it as DIBOL.
The data was stored in ISAM files with, overlayed record definitions and numbers stored as Zoned Decimal (The sign is stored in the rightmost digit with
a “p” through “y”).
The company didn't want to pay for a DIBOL compiler, so using lex/yacc I wrote a simple parser for the the schema definitions and managed to decode all the data files and extract it all as JSON.
Like the article, I can't remember where I left my glasses, but can remember code and techniques from 40 years ago.
