> But, sure, be a douche about it if it makes you feel more superior. Whatever.

No, but don't try to assert conjecture as facts. "Whatever"

> So, are you saying that PKZip supported running on the pre-XT ROM BASIC OS, as well as PC-DOS/MS-DOS?

Now you're being a douche, no? I said that the hardware had cassette tape access.

The IBM PC, and PCjr both has the hardware to access tape drives. And yes you could access the cassette tape routines, INT15, 0/1/2/3 ( https://stanislavs.org/helppc/int_15.html ) through DOS, though as you allude to, there was little need to do so.

However BASICA could load programs from tape. https://www.youtube.com/watch?v=KTmzUBb924A

There, something else you can learn today. I'll leave it to you to discover exactly what.