HP SureStore CD-ROM Server/Tower User's Guide - 5967-2149

9-12 Troubleshooting
Disc Changer
Access Problems
❏ Disc changers, with up to 8 discs each, are supported.
Up to 56 CDs are supported through LUN (Logical Unit
Number) addressing.
The server has a general parameter, JukeBoxLockTime, which
sets how long a user has exclusive access to a CD during a data-
read operation. This is to prevent disc-changer flutter in order to
optimize access speed when many users are accessing different
discs in the same changer.
Disc changer flutter can occur if a user requests access to a CD
when another user is already reading data from a different CD
in the same disc changer. The changer may then attempt to
service both requests by repeatedly changing between the two
CDs and transferring a small amount of data each time. Because
of the relatively long time needed to change CDs, the data-trans-
fer rate to both users will become unacceptably low.
Use the JukeBoxLockTime parameter to ensure that when
there are simultaneous requests for access to different CDs, a
sizable block of data is transferred to each user before the CD is
changed.
•
If the JukeBoxLockTime parameter is set too low, the data
transfer rate will be unacceptably low.
•
If the JukeBoxLockTime parameter is set too high, the
drive will time out a second user’s request before the first
user’s access is completed. This will result in users receiving
a “CD-ROM not available” notice.
The default setting is 0 seconds, which disables this function;
you can adjust this value.