Funny project...

Tried to run SHELL from QBASIC, but it crashes:

  D:\qbasic.exe has encountered a problem and needs to close.
  
  Reason:  illegal instruction
  Address: 0x00002fee

DOS interrupt support is still limited. Running SHELL would essentially require implementing a full MS-DOS COMMAND.COM, which is a significant undertaking.

Ralph browns interrupt list could go a long way to getting stuff working.

Oh, I did exactly the same :D