The earliest versions of the first C compiler known to exist

Compiler structure and C’s original design goals

• Thread starts by noting the recovered compiler is not single‑pass; some expected it to be, given C’s reputation for being single‑pass‑friendly.
• One view: early C syntax (no typedef, declarations must precede use, default int, simple pointer rules, register hint) seems intentionally shaped to allow a naive one‑pass compiler that emits code as it parses.
• Others are unsure this was ever explicitly stated by the language’s designers; some behavior (e.g., calling undeclared functions as int) is framed as B‑compatibility relics rather than carefully planned design.

Old C syntax and semantics (extern, auto, arrays, parameters)

• Early code uses extern inside functions just to say “this global is defined elsewhere”; later C style prefers such declarations at file scope or in headers.
• auto originally meant “automatic storage duration” (stack/local); because this was the default it was almost always redundant.
• In C23, bare auto switches to C++‑style type deduction. Some see this as reasonable reuse of a dead feature; others dislike “type inference” and cross‑pollination from C++.
• “Sizeless” arrays are effectively used as pointers; early pointer syntax and array handling came directly from B.
• K&R‑style parameter declarations (names in the parentheses, types on following lines) and odd forms like int argv[]; or char argv[][]; reflect pre‑ANSI C calling conventions.

The waste() function and space allocation tricks

• A recursive waste() function that explosively nests calls appears; commenters speculate it pads the binary to test instruction offsets, force code past certain memory boundaries, or reserve static space.
• Linked Ritchie notes clarify: early compilers sometimes deliberately allocated temporary storage over the program’s own initialization code to save memory; waste() plus the ospace variable is part of that scheme.
• This is described as an archaic but clever response to severe memory limits; modern equivalents would use linker scripts or self‑relative data instead.

Bootstrapping C from earlier languages

• Multiple comments outline the lineage: BCPL → B (initially in BCPL, then self‑hosted) → “New B” → C via continuous evolution of the same compiler, not a clean rewrite.
• New features were added to the compiler, then used in the compiler’s own source; at times, older compilers could no longer build the current one, so people simply copied a newer binary from colleagues.

Early C, Unix, and mainframe ports

• Discussion of early C compilers for PDP‑11 UNIX, Honeywell GCOS, and IBM 370‑class systems, including ports layered over different OSes.
• Oracle’s database history is brought up: early versions in PDP‑11 assembly, then a C rewrite for portability; lack of widely available mainframe C compilers led some vendors to fund or build their own.
• Commenters reminisce about early 80s/90s mainframe C ports, encoding issues (ASCII vs EBCDIC), and wonder whether those compilers or Oracle v2/v3 binaries still exist.

C standardization, committees, and safety

• Debate over standards bodies: some criticize WG14 for aligning C with C++ and for decisions like repurposing auto; others argue disused features are fair game and users rarely demand safety over performance.
• Several point out existing safety tools (asan/ubsan) and argue they should be used more, even in production.
• Broader discussion compares standards committees to “governments” with feature champions and voting cycles, though others insist committees are not analogous to governments.
• On security and memory safety, some argue industry users historically favored speed over checks; others cite older languages with built‑in bounds checking as evidence that safer designs were known but not followed in the C ecosystem.

Is C actually “simple”?

• Strong disagreement here:
  • Some insist C is “simple” or a “thin layer over a von Neumann machine”; its appeal is direct manipulation of memory, structs, and pointers.
  • Others respond that while C is small, it’s not simple: implicit promotions, tricky pointer rules and provenance, undefined behavior, complex aliasing, a hard‑to‑implement preprocessor, and parsing that historically needed lexer hacks all add semantic and tooling complexity.
• Comparisons are made to languages like Go, Rust, Zig, Modula‑2, Oberon, Pascal, Forth, Lisp; views differ on which are simpler and at what level (syntax vs semantics vs memory model).
• A recurring theme: C makes it feel like you’re dealing with “raw addresses,” but many such operations are technically undefined; the mismatch between mental model and spec is seen as a major source of bugs.

Historical tooling and culture

• Questions and anecdotes touch on:
  • Early Unix development environments: line editors, primitive shells, no preprocessor or make in the very beginning, short identifiers, limited RAM.
  • Extremely terse error messages in old tools and libraries; some modern software retains this style more by taste than necessity.
• Several commenters reflect on “standing on the shoulders of giants,” the cyclical rediscovery of memory safety, and generational tension between “cool kids” and older systems programmers, while acknowledging that modern safety work builds on the earlier low‑level foundation.