Section 13: Accessing Your Mass Storage System 266
The HP 82900-Series 5ΒΌ-Inch Flexible Disc Drives have the following drive numbers. (The drive numbers appear on the front panel of each unit.)
  HP 82902M Flexible Disc Drive (single master)   DRIVE 0
  HP 82901M Flexible Disc Drive (dual master)   DRIVE 0, DRIVE 1
The HP 9895A 8-Inch Flexible Disc Drives have the following drive numbers.
  HP 9895A Option 010 (single disc)   DRIVE 0
  HP 9895A (dual disc)   DRIVE 0, DRIVE 1
For information about drive numbers of other Hewlett-Packard disc drives, refer to the instructions for those devices.
The Mass Storage Unit Specifier (msus)
The mass storage unit specifier (msus) is a character string that combines the HP-IB select code, the address of the disc drive unit, and the drive number to specify the location of a particular disc on which a file is located.
The msus has the form:
  ": device type [interface select code   device address   drive number] "  
All msus character strings begin with a colon (:).
The device type identifies the type of mass storage device being accessed, D or d for disc.