You know, I haven't seen anyone challenge the whole IBM 5100 thing, and I think that's a key problem in his story.
Mr. Titor's whole purpose for travelling back in time was to fetch an IBM 5100, which could supposedly translate between "APL, Basic, and Unix". Now, it is a fact that the 5100 could run either APL or Basic. Further, its processor could run two rather different instruction sets: it used one to run APL programs, and one to run Basic programs.
However, it could not translate between them. There was a front-panel switch that changed it from being an APL computer to being a Basic computer. It was two completely separate modes. There was no crossover.
Further, the 5100 could not run Unix, either then or now. It didn't have enough processor power nor memory, and it did not support hard disks at all.
Going one more step, Unix is NOT a language like APL or Basic. You can
translate from APL to Basic, but it is ridiculous to talk about translating between Basic and Unix.
And finally, the fact that he mentions APL and Basic at all puts the final nail in the coffin. All of the historical computing web sites on the IBM 5100 mention APL and Basic (and 1975), which would explain where he got the terms, but both languages are virtually irrelevant today, and will only grow more so as time goes on. He is supposed to bring this computer back to 2036 in order to fix up a bunch of legacy code, but the fact is there is absolutely no "legacy code" written in APL, and there is no "legacy code" written in the primitive version of Basic built in to the IBM 5100.
It's all fun to think about, but it's a crock.