Workspace restore limits for system variables and definition fidelity

A workspace backup using )SAVE or ⎕WS is intended to capture the active APL environment, including defined functions, variables and a portion of system state, so that a later )LOAD or ⎕WG restores the environment to the saved point.

The documented capability covers global names and function definitions, with verification typically discussed in terms of canonical representations and name lists. The scope of system variable persistence is less clearly bounded. Some system variables such as ⎕IO and ⎕ML are described as being restored, while other presentation or session variables are noted as potentially reverting to defaults after load.

Platform independence is described as holding within the same interpreter version, and pending execution or halted computations are stated not to resume after load. The precise set of preserved system variables and the version compatibility boundaries for a reliable restore remain an open design decision.

Which system variables are guaranteed to be saved and restored by )SAVE / ⎕WS? Does the workspace format remain compatible across interpreter patch releases within a major version? Is any execution or evaluation state ever preserved across a load operation?