This is a driver for SCSI Media Changer devices, for example tape libraries or CD-ROM/MOD Jukeboxes. This is for real jukeboxes with a scsi device for the changer robot, like this one:
Vendor: HP Model: C1553A Rev: 9503 Type: Sequential-Access ANSI SCSI revision: 02 Vendor: HP Model: C1553A Rev: 9503 Type: Medium Changer ANSI SCSI revision: 02 ^^^^^^^^^^^^^^
These multi-lun CD-ROM changers toys with one LUN per slot are not supported by this driver.
The latest release tarball can be downloaded here. It contains userspace tools to control the driver and a kernel patch which adds the driver itself to the linux kernel.
Updated patches for newer kernel versions are usually available from my kernel patch area.
Starting with release 2.6.13 the linux kernel ships with the scsi changer driver included, so no patches are needed any more.