The Assembler (Basic Assembler Language or BAL) was for the Univac 9300 and 9400, clones of the IBM 360. Univac originally made and sold the 1100 series, with the Exec 8 O/S. The 1100 was a 36-bit machine, very successful in airline reservation systems, petroleum exploration, etc. but it was incompatible with IBM's 360 architecture. Univac developed the 9000 so IBM customers could easily convert.

The 9300 I programmed had 32K, tape drives, card reader & punch. It ran NCOS (Non-Concurrent OS). It had no virtual memory, so we had to write our own "overlays", sections of code that were loaded at beginning and end of a run, for initialization and wrapping up. No console, just sixteen lights to display error numbers, and eight butterfly switches for writing directly to memory.

Imagine running an insurance company on 32K!