Tales from Mainframe Modernization

a year ago

The author worked on transpiling mainframe languages like COBOL, JCL, and BASIC to Java using Rust.
COBOL uses base-10 numerics, with variables declared using 'PIC' clauses (e.g., PIC 9(3) for a 3-digit number).
COBOL supports 'REDEFINES' to alias memory regions, allowing variables to be referenced in different languages (e.g., Spanish).
String parsing in COBOL involves defining memory regions with named segments, enabling clever string manipulation.
Early exits in COBOL batch jobs were sometimes triggered by dividing by zero to force an abnormal termination.
A mysterious file contained the first 800 natural numbers as string constants, with no clear explanation.
The UNIX 'dd' command is named after JCL's 'DD' statement, which defines data streams for batch jobs.
The author, Akshay, is building tangled.sh, a decentralized code-collaboration platform.

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