Legacy Glossary

Browse 42 legacy terms defined in plain English, from the cultural dictionary of computing.

42 Legacy Terms

Barnacle Code
Code that has accumulated in awkward layers around a system over time, sticking to it through patches, exceptions, and fear of removal. In engineering slang,...
BIOS
BIOS, or Basic Input/Output System, is firmware stored on a chip on the computer's motherboard that initializes and tests hardware components during the boot...
Blowfish
A symmetric block cipher designed by Bruce Schneier in the 1990s, historically popular as a fast general-purpose encryption algorithm. While still notable in...
Boat Anchor
A system, tool, or dependency seen as heavy, obsolete, and mostly useful for dragging everything else down. In engineering slang, calling something a boat...
brownfield
A software project built within the constraints of existing systems, codebases, and infrastructure, as opposed to a greenfield project that starts from...
Brownfield
A project that involves modifying, extending, or maintaining an existing codebase with established patterns, technical debt, and real users. Most professional...
Brownfield
Brownfield in software development refers to a project that involves working with existing, legacy codebases and infrastructure rather than building from...
Bug Mine
A part of the system where hidden bugs are densely packed, waiting to explode when someone touches the code. In engineering slang, a bug mine suggests old...
COBOL
Common Business-Oriented Language, one of the oldest programming languages still in active use. COBOL runs an estimated 95% of ATM transactions and 80% of...
Code Cave
A hidden or obscure part of a codebase where strange, old, or specialized logic lives out of sight. In engineering slang, code caves are where people go when...
Code Coffin
A darkly funny term for a place where old code is buried but still present, usually because nobody has fully deleted it. In engineering slang, a code coffin...
Code Dark Ages
A joking term for an older era of a codebase when standards, tooling, or engineering discipline were much worse than they are now. In team lore, the code dark...
Code Dinosaur
A joking term for very old code, tooling, or sometimes a developer associated with long-established practices. In engineering slang, code dinosaur can be...
Code Eulogy
A humorous or sincere farewell to a retiring codebase, system, or piece of tooling that had a long and memorable life. In engineering culture, code eulogies...
Code Fossil
A very old piece of code preserved in place long after its original context has faded. In engineering slang, a code fossil is interesting historically and...
Code Funeral
A humorous term for the final retirement of a system, feature, or code path after a long life. In engineering culture, a code funeral may be informal, but it...
Code Ghost
A mysterious leftover behavior, dead dependency, or seemingly absent piece of logic that still affects the system. In engineering slang, code ghosts are the...
Code Inheritance
The body of old code, assumptions, and maintenance obligations a team receives when taking over a system. In engineering slang, code inheritance emphasizes...
Code Mine
A hazardous zone in the codebase filled with hidden pitfalls and fragile assumptions. In engineering slang, code mine overlaps with bug mine, but often...
Code Museum
A repository or system kept around mostly as historical reference rather than for active use. In engineering slang, a code museum can be educational, but it...
Code Retirement
The deliberate removal or shutdown of code that has reached the end of its useful life. In engineering slang, code retirement is often healthier than...
Code Ruins
The remains of old code structures, APIs, or architectural ideas that no longer function as intended but still occupy space and influence decisions. In...
Common Block
A Fortran language construct that defines a named block of shared memory accessible by multiple program units, allowing subroutines to share data without...
Copybook
A COBOL source code file that defines data structures and is included into other programs at compile time via the COPY statement. Functionally equivalent to...
Data Encryption Standard
Data Encryption Standard is the historical symmetric cipher standard based on DES, now retained mainly for legacy context. Security teams use it to enforce...
DES
DES is an older symmetric block cipher with a 56-bit key that is now considered insecure against practical brute force. Security teams use it to enforce trust,...
EBCDIC
Extended Binary Coded Decimal Interchange Code — an 8-bit character encoding created by IBM for mainframes. Predates and is incompatible with ASCII, and still...
Fortran
The first widely used high-level programming language, originally developed for scientific and engineering computation. Fortran (Formula Translation) remains...
Here Be Dragons
A code comment warning that the following section is dangerous, poorly understood, or likely to break if modified. Borrowed from the medieval cartographic...
JCL
Job Control Language — a scripting language used on IBM mainframes to instruct the system on how to run batch jobs, specifying programs to execute, datasets to...
MD5
MD5 is a legacy cryptographic hash function that is fast but broken for collision resistance and unsuitable for secure integrity checks. Security teams use it...
NTLM
NTLM is a legacy Microsoft authentication protocol that uses challenge-response and is frequently targeted for relay or cracking. Security teams use it to...
Old Faithful
A reliable tool, service, or habit that keeps working dependably even if it is not flashy. In engineering slang, old faithful can be affectionate praise for...
Pascal
A structured programming language designed primarily for teaching good programming practices. Pascal influenced many subsequent languages and was popularized...
Perl
A high-level, general-purpose scripting language originally designed for text manipulation and report generation. Known as the 'Swiss Army chainsaw' of...
Shim
A thin layer of code that intercepts and translates API calls, providing compatibility between old and new interfaces or filling in missing functionality....
Ship of Theseus (Codebase)
The philosophical question applied to software: if every line of code has been replaced over time, is it still the same project? Every long-lived codebase...
Spaghetti Code
Source code with a tangled, incomprehensible control flow — typically featuring excessive goto statements, deep nesting, and no discernible structure. The kind...
tech debt bankruptcy
The point at which accumulated technical debt becomes so severe that incremental repayment is no longer viable and the only practical option is a complete...
Token Ring
A LAN protocol (IEEE 802.5) in which networked stations are arranged in a logical ring and a special 'token' frame circulates continuously — a station may only...
Working Storage
A section of a COBOL program's DATA DIVISION where variables that persist for the life of the program are declared. Unlike LOCAL-STORAGE (per-invocation),...
Y2K
The Year 2000 problem — a class of bugs caused by software storing years as two digits, making the year 2000 indistinguishable from 1900. The largest...

Related Topics