They still exist. You can still run OS 2200 on a Clearpath Dorado.[1] Although it's actually Intel Xeon processors doing an emulation.
Yes, indexing strings of 6-bit FIELDATA characters was a huge headache. UNIVAC had the unfortunate problem of having to settle on a character code in the early 1960s, before ASCII was standardized. At the time, a military 6-bit character set looked like the next big thing. It was better than IBM's code, which mapped to punch card holes and the letters weren't all in one block.
Yes, indexing strings of 6-bit FIELDATA characters was a huge headache. UNIVAC had the unfortunate problem of having to settle on a character code in the early 1960s, before ASCII was standardized. At the time, a military 6-bit character set looked like the next big thing. It was better than IBM's code, which mapped to punch card holes and the letters weren't all in one block.
[1] https://www.unisys.com/siteassets/collateral/info-sheets/inf...