Zenith Z-100 Series, Руководство пользователя, Страница: 15 / 150

WINCHESTER SUPPLEMENT
The PREP Utility
Enter 4 (the hexadecimal equivalent of the number of
read/write heads) and press the tl
ag ] key. Next, the
screen will display:
Enter number of cylinders in hex:
This number is equal to the total number of tracks divided
by the total number of read/write heads. Enter 132 (the
hexadecimal equivalent of the number of cylinders) and
press the ~
~ key. T h e screen will now display:
Enter reduced write current cylinder in hex:
Toward the hub of a hard disk, where the circumference
of each track is smaller, some Winchester systems re-
quire that less electrical current be applied to the write
head to avoid having magnetic pulses overlap adjacent
tracks. The Miniscribe Mod II 2012 does not require re-
duced write current. Therefore, a value greater than the
largest cylinder number will be entered. Enter 200 (the
number in hexadecimal of the cylinder where the current
applied to the write head is reduced to avoid overwriting
track bounds) and press the ~ g g] ke y . Next, the
screen will display:
Enter pre-comp cylinder in hex:
Disk storage devices operate by creating magnetically
polarized areas on the disk surface that correspond to
the presence or absence of "bits" (the smallest unit of
measure in computer data and memory) in the information
being stored. Since "like" charges repel and "unlike"
charges attract, it is possible for the charged areas on
the disk surface, which represent the data, to "shift"
slightly if they are closely spaced after being recorded.
If such a shift occurs, reduced reliability will result.
Precompensation refers to the intentional shifting of data
during the recording process so the combined result of
precompensation and the natural shift (which cannot be
prevented) places the data in the desired position. On