PCjs contains the following IBM PC BASIC ROMs:
These built-in versions of BASIC were also referred to as Cassette BASIC, because no disk drive was required. Only the original IBM PC (Model 5150) actually provided a cassette interface, but IBM continued to use that name to describe the built-in BASIC, at least up through the IBM PC AT (Model 5170).
Both versions of Cassette BASIC were 32Kb and spanned physical addresses 0xF6000-0xFDFFF. They were produced by Microsoft, and unlike the IBM PC BIOS ROMs, no source code listings of these BASIC ROMs were ever published.