Anecdotes [relocation bits]

Relocation bits, which became necessary when modules could be compiled separately and placed in a library for integration at runtime, are still relevant today. Two letters from 1961 demonstrate the kinds of analysis that led to the evolution of relocation bits in the early years. The first letter discusses a recent proposal made by IB (the SHARE symbol for IBM) to the committee, the history of relocation bits, the reason for various evolutionary decisions, and the new IBM proposal´s impact. The second letter suggests a generalization of the proposal, in particular to eliminate the distinction between program and data, as far as loading blocks of information into storage for execution. This was intended to simplify the scheme for relocation bits. This paper documents the state of module relocation at the time.