Mac OS X Server: What is System Disk 2.3.1 For?

System Disk 2.3.1 was posted to ftp://ftp.apple.com/developer/macosxserver/utilities/SystemDisk2.3.1.smi.bin.

What is new in System Disk 2.3.1, and what can it be used for?
System Disk 2.3.1 supports device 1 (slave) IDE/ATA devices. However, since the installer for Mac OS X Server will use the System Disk application on the installation disc, there is no way to install Mac OS X Server directly onto a slave IDE/ATA device. This version of System Disk is not needed for Mac OS X Server1.0-2 or earlier.
Published Date: Feb 18, 2012