I worked with SPERRY and later UNISYS 1100 machines. Big main frames. They have a 36-bit architecture and the nice part of if is that you can always read the octal dump, because a 36-bit word was always the complete instruction. With "multi-byte" instructions in a dump it is a bit more difficult to find the start of an instruction. SPERRY had a character set called FIELDATA. It is 6-bit (uppercase only), so you fit put 6 characters in one (36-bit) word. Later, somewhere around 1989, they introduced the 2200, the smaller version of the 1100, but runs the same instruction set. I vagely remember that the 2200 line was called the "A-series", as there was also a "B-series" as a result of the merger of SPERRY and BURROUGHS to the new UNISYS. But, I am not sure. I left that company (and fine 1100) in 1990 ... - Henk.