Maxtor 1925 - Manual (Page 33)

Installation
4-8 Quickview 40 20/30/40GB AT
4.3.5 Alternate Capacity (AC)
For user capacities below 66,055,248 sectors (32GB), inserting the AC
jumper limits the Number of Cylinders field 1 to a value of 16,383, as
reported in IDENTIFY DEVICE data word. This allows software drivers
to determine that the actual capacity is larger than indicated by the
maximum CHS, requiring LBA addressing to use the full capacity.
A summary of these effects for the Maxtor Quickview 40 drives is
shown in the following table:
Figure 4-5 AT Connector and Jumper Location
AC JUMPER OUT AC JUMPER IN
20GB
C=16,383
H=16
S=63
LBA=40,718,160
C=4,092
H=16
S=63
LBA=39,876,479
30GB
C=16,383
H=16
S=63
LBA=60,058,656
C=16,383
H=16
S=63
LBA=66,055,247
40GB
C=16,383
H=16
S=63
LBA=80,293,248
C=16,383
H=16
S=63
LBA=66,055,247
Pin 1 JPM Pin 1
29.78±0.50
(to pin center)
4.55±0.50
7.22±0.50
(to pin center)
Pin 1 of AT Connector
Connector Side
CL