This is a 1.44M disk image in raw format.  The disk should be
labelled:

Dosbasic.dsk      MS-DOS/GW-Basic and Supplemental MS-DOS and
                  SmartDrive Installation Programs

This is the original DOS for the 1000RLX ("A" version), models
25-1452 and 25-1453.  It is unlikely to be useful on other models.
