It's basica.com from IBM DOS 4, modified to replicate the one that ships with OS/2. It's running in a Windows 2K window on a clone: ie it is been de-IBM'ed. As with the DOS5/OS2 versions, this has rombasic attached. Unlike these versions, the rombasic actually works.
One should note that the only difference between versions 4.00 and 3.40 is the version number and the copyright. Vers 4 says "Version A4.00 Copyright IBM Corp. 1981, 1988" on line 2, and does not have ROMBASIC attached. Vers 3.40 is different: which see.
- PCE: www.hampa.ch/pce/index.html
- MOVBASV5 (tool for freeing ibm basic) - lightly hacked
- MASM 5 (to recompile movbasic.com)