History
Early capability systems
Capability systems emerged in early computer systems as a way to represent and protect authority: possession of a protected reference determines what an operation may access.
Why it matters
The earlier work shows that capability security is a long-developed model, while CHERI’s contribution is a contemporary, compatible hardware-software realisation.
In brief
Capability systems emerged in early computer systems as a way to represent and protect authority: possession of a protected reference determines what an operation may access. CHERI adapts that lineage to modern processors and existing software ecosystems.
Key considerations
1. Protected references
Authority is carried by references that untrusted software cannot arbitrarily forge.
2. Least authority
Software receives the objects and operations it needs instead of broad ambient access.
3. Practical adaptation
Modern systems must combine these principles with virtual memory, C/C++, concurrency and current processor constraints.
Evidence and caveats
Historical systems differ greatly from CHERI in architecture, workload and implementation. Use the comparison to understand principles, not to imply equivalence.
Use dated primary project, funder and provider records. Separate what was planned, demonstrated and subsequently delivered.