The 7908 is a 10Mb disc drive.
My first HP3000, a Series 30, had one drive, a 10 Mb 7908,
configured as a split drive. One 5Mb logical drive was
LDEV 1 and held the operating system software,
which was delivered on three 8" floppy discs.
Eventually MPE got too big for the 5 Mb drive and our
CE reconfigured the drive as a single 10 Mb drive.
Then we got a 7920 50 Mb drive and had scads of room
for our 16 users.
Cecile Chi