Digital Equipment DEC 3000 Series Service Information page 43

Storage Devices,
RRD42 Disc
Drive Jumper
Settings
Mode Select
Jumper
Continued
Table 2–9 shows the RRD42 disc drive jumper settings.
The mode select jumper (Figure 2–6) is a user-selectable feature.
If you do not select the correct mode, the drive does not operate
properly.
The mode select jumper has two modes:

Mode 0—default mode
When the drive is shipped from the factory, the jumper is not
installed. The drive operates in the default mode with a block
size of 2Kbytes. Use mode 0 with the MS–DOS and SCO UNIX
operating systems.

Mode 1—standard mode
When the jumper is installed, the drive operates in standard mode
with a block size of 512 bytes. Use mode 1 with the OpenVMS
and ULTRIX operating systems.
The mode select jumper does not affect other operations.
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