HP C2233 Product Description Manual page 51

Assembly
Descriptions
Head/Disk Assembly
DRAFT
10/24/90 11:07
will be returned to the host without the delay of a media
access. However, the controller is optimized to return any
. requested data to the host as fast as possible.
If a new READ command requests data not contained in
the buffer while the drive is performing a Look Ahead
Read, the process is aborted, and the drive will immediately
seek to the new track with no effect on access or transfer
performance. Filling the track buffer with unrequested data
has a lower priority than delivering requested data. Other
conditions that may affect completing a full-track READ
before receiving the next READ command are: sector
spares on the track being read, head position relative to the
requested data, transfer size, and the host transfer rate.
The assemblies in the disk drive include the head/disk
assembly (HDA) and the drive electronics/controller
printed-circuit assembly (PCA). The sealed HDA contains
the mechanical and electromechanical assemblies of the
disk drive. The drive electronics/controller PCA provides
the SCSI interface and all electronic control over the HDA.
The following paragraphs describe the major functional
components of each assembly.
The head/disk assembly (HDA) contains disks, heads, an
actuator assembly, head interface circuits, atmospheric
controls, vibration isolators; and a spindle assembly. A
stainless steel baseplate and cover provide the supporting
structure for these parts. The entire assembly is sealed and
is not field repairable.
Disks
The disks are 3.5-inch (95 mm) diameter aluminum
substrates with sputtered thin-film surfaces. The disks
are mounted on the spindle assembly in stacks of three
Product Features 3-11