Western Digital WD 1003-RA2, Руководство пользователя

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PROBLEM: Controller does not format a Seagate ST225 to 30 MB.
CAUSE: The ST225 is a 20 MB MFM drive. The ST238 is a 30 MB RLL drive. This
is a good time to point out the differences between RLL and Modified
Frequency Modulation (MFM) disk drives and controllers. First, RLL
equipment is able to record 50% more data on the drive. Second, RLL
drives must be physically formatted with 26 sectors because of the greater
data density. This leads to an important point:
DO NOT UNDER ANY CIRCUMSTANCES CONNECT A RLL
CONTROLLER TO AN MFM DRIVE!
RLL controllers physically format any attach drive into 26 sectors.
Therefore, the RLL controller squishes 26 sectors onto a drive designed for
17 sectors. Squishing the RLL data onto an MFM drive results in corrupted
data, to say the least. Finally, the chip sets on RLL and MFM controllers
significantly differ as a result of the first and second points.