HP C2233 Product Description Manual page 52

3-12 Product Features
(HP C2233), four (HP C2234), or five (HP C2235) disks.
Data is stored on both surfaces of all disks except for the
bottom surface of the bottom disk which is reserved for
servo information.
Heads
Five (HP C2233), seven (HP C2234), or nine (HP C2235)
MIG (Metal-In-Gap) data heads in the HDA write and read
user data. An additional thin mm head in each unit is used
to recover the servo information from the bottom surface of
the bottom disk.
Actuator Assembly
A rotary act:uator positions the read/write heads. A
shipping latch captures the actuator arm at the inside
diameter of the disks (away from user data) whenever
power is removed from the disk drive. This prevents the
heads from moving over data until power is applied and
the disks are spinning, causing the heads to fly at a safe
distance above the disk surfaces. During the power-up
sequence, the processor releases the latch, allowing normal
movement of the heads.
Head Interface Electronics
The head interface circuits (located inside the HDA),
process the data signals transferred between the read/write
heads and the drive electronics/controller PCA. These
circuits include write drivers which provide the necessary
current
to
the heads dming write operations, and read
preamplifiers that amplify data read from the disk before
transferring it
to
the read/write circuit on the drive
electronics/controller PCA. Additional functions performed
by the head interface include head selection and write
control.
DRAFT
10/24/90 11:07