prometeu-runtime/discussion/lessons/DSC-0001-runtime-learn-legacy-import/LSN-0007-historical-retired-fault-and-input-decisions.md

id	ticket	title	created	tags
LSN-0007	legacy-runtime-learn-import	Retired Decisions 004-005 (Historical Notes)	2026-03-27	migration tech-debt

Retired Decisions 004-005 (Historical Notes)

This file keeps historical rationale from decisions that were retired after being absorbed by specs.

Status: pedagogical / historical (not normative).

Mapping

• Retired 004-host-fault-taxonomy.md
  • Canonical source now: ../specs/16a-syscall-policies.md
• Retired 005-v1-vm-owned-input-intrinsics-and-language-agnostic-surface.md
  • Canonical sources now:
    • ../specs/06-input-peripheral.md
    • ../specs/16-host-abi-and-syscalls.md
    • ../specs/16a-syscall-policies.md

Historical Rationale Snapshot

1) Why input left syscall path in v1

• repeated input reads through syscall would force large value transport;
• deterministic frame snapshot works better as VM-owned intrinsic surface;
• frontend syntax should stay language-specific while VM contract stays language-agnostic.

2) Why fault taxonomy was tightened

• operational domain outcomes should be returned as status;
• Trap should represent structural ABI misuse from guest side;
• Panic should represent runtime invariant break;
• broad Unavailable usage was causing severity ambiguity.

Practical Outcome

• Input is VM-owned and deterministic per logical frame.
• Host-backed syscall ABI remains structurally stable.
• Domain agendas now anchor fault discussions on spec 16a, not on retired decisions.