Bootstrap ROMs

Bootstrap ROMs

The Centurion went through several different revisions over the years, utilizing different CPUs such as the CPU5 or CPU6, as well as different drives from Tape Drives to Hawk Drives to Finch Drives. As such, the manner in which system was bootstrapped changed over the years. The following is a list of all known bootstrap ROMs, there code (if backed up), and which machine they were used in.

12-byte diode ROM

CPU4/EE200, bootstrapped an autoloader MMIO card that would then boot the Hawk

1702 EPROM

CPU4, located on the DSK/AUT card, boots a Hawk, but also looks as SS3 and SS4

Dual 128 byte PROM

CPU4, located on late revision DSK/AUT, depending on installation location, would boot Hawk or Tape

6349 PROM v1

Early CPU5, located on backplane, depending on stored program, could load Hawk WIPL or Floppy WIPL

6349 PROM v2

Late CPU5, located on backplane, could load Hawk WIPL or Floppy WIPL, but also looked at SS1 for DIAG

6349 PROM v3

CPU6, located on backplane, would load a D= prompt, from there Hawk, Floppy/Finch, or CMD drives could be selected