User guide
2.
DISK FORMAT CHECK
Media defects may occur on the surface
of
the disk. A media
defect is defined
as
a read error that occurs more than ten times at
anyone
track location. If not attended to, these physical defects
might show
up
as
error signals from your
computer
when running
a
valid program. Or perhaps a valid program
just
will not function
correctly.
The cyclical redundancy check (CRC)
function
checks
for
bad
sectors
on
the disk and reports the number and location of each of
them. Track reassignment
is
used to handle the defect areas.
The
controller tries
to
read each 512 byte sector
to
verify
that
it
is
'good' (has a correct
CRG).
If it gets a bad CRC after twenty read
attempts, it
will rewrite the sector to reset the CRC. This usually
takes 1 to 2 minutes.
3. READ CONTROLLER CODE VERSION #
This option displays the version
number
of
the Corvus 2-80
firmware residing on the hard disk drive.
4. HEAD SERVO TEST
This test alternately reads 128 byte sectors at
disk
address 0 and
at the high disk address. This causes the heads
to
move back and
forth across the
platter surfaces
of
the disk
to
check
if the servo
mechanism is working
properly. This test is mainly useful
to
verify
that the drive
will actually read data and move its heads.
5. MANUAL CONTROLLER DIAGNOSTIC
This option should not
be
used unless
under
direct
supervision
of Corvus customer service
personnel.
6. UPDATE CONTROLLER CODE
This option allows the update or initial installation
of
controller
code
on
the Corvus drive. This code resides on protected tracks
of
the hard disk. Normally this code cannot be
written
to
or read by
the user (even accidentally). However it can be made
accessible
(to writing) by
turning
on the format switch. This option replaces
the separate program CCODE.COM that had similar capabilities.
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