These are 1.44M disk images in raw format.  The disks should be
labelled:

Msdos1.dsk      MS-DOS 5.0 disk 1 - Startup, Utilities, & Installation
Msdos2.dsk      MS-DOS 5.0 disk 2

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