The a.out format

• In the beginning of time (1991) we had a.out:

  • No relocation at load and run time. Every shared library must have a fixed loading address.
  • There needs to be a central authority for library loading addresses to avoid collisions. By today we would have run out of addresses to give.
  • The virtual memory space of programs becomes very fragmented.
  • A library must maintain throughout it's life and version a rigid entry point table where entries can be appended but never retired.