I notice that various software in real mode(CheckIt Diagnostics, PC-check) seem to have some weird kind of issue making it eventually execute a literal INT 0h(Opcode CD00), making MS-DOS report a divide error or divide overflow(depending on the software. Divide error for CheckIt on the Pentium in real mode(no issues running it in protected/V86(EMM386/QEMM) mode). Divide overflow a bit into loading PC-Check(one of the very first loading steps it's mentioning)).

QAPlus/Pro doesn't report any errors other than a keyboard(or 8042 bug) one? It doesn't seem to test much?