Development Plan: Porting Python to PDP-10

Overview

• Objective: Enable execution of Python code on PDP-10 systems.
• Challenges: 36-bit architecture, no POSIX, limited memory, non-standard word size.
• Advantage: Existing implementations of UTF-8 and UTF-9 by Mark Crispin.

Prerequisites

• Unicode support
• KCC

Phase 1: Feasibility & Toolchain Setup

• Choose a Python version:
  • MicroPython for embedded profile
  • Python 2.x for simpler VM logic
• Toolchain Options:
  • Emulators: SIMH, KLH10
  • Document Processors: Runoff Formatter in Python
  • Compilers: MACRO-10, BLISS, C10, KCC or modern cross-compiler

Phase 2: Environment Design

• Target OS:
  • TOPS-10 – minimal
  • TOPS-20 – richer
  • ITS – hacker-friendly
• Implement:
  • Basic C runtime wrappers
  • File I/O and memory emulation

Phase 3: Incremental Port

• Adapt VM or bytecode interpreter:
  • Replace types with PDP-10-friendly abstractions
  • Handle word size in operations and memory model
• Stub out unsupported libraries

Phase 4: Debugging and Testbed

• Use emulators to run scripts
• Write and test simple programs
• Log outputs and debug steps

Phase 5: Extensions

• Interface with MACRO-10 routines
• Define new UTF8 and UTF9 macros, with conversion routines
• Optimize memory handling

Deliverables

• Source code and build scripts
• Memory/architecture notes
• Mini stdlib subset
• Working test suite

Optional Future Work

• Cross-assembler in Python
• ITS scripting support
• Browser-based demo (SIMH + Python)