Alternate Capacity Jumper
Some older computers as well
as the Alesis Masterlink may "hang" or display jibberish if the BIOS detects
hard drives with more than 4092 cylinders or approximately 33.8 GB (32GB).
The 40GB drives in question typically have 16,383 cylinders! At the
UBER GEEK level, the drive reports its status via "words" 60 and 61, the
alternate capacity jumper sets the "default translation geometry" to 4,092
cylinders limiting the apparent capacity of the ST340810A and the
ST340823A drives to 33.8GB (32GB) by "freezing" the status words at a value
below the problem barrier point.
However, the ATA feature
set includes the sub-command "F1h" to Report Full Capacity and then fill
in the "real" value of words 60 and 61 after the BIOS scan and once
the Operating System (OS) takes over.
As an example, while the
computer hardware may not support or report the full size
of the drive, Windows 98 and newer operating systems interrogate
the drive a second time using the F1h command to take full advantage of
the drive's capacity.
40GB is over 10-times the
space originally shipped with Masterlink and twice the supported drive
size. No one with the 40GB drive upgrade has actually found whether
or not there are actually limitations, such as the number of playlists,
or "songs" or total contiguous recording time.
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