3.3 Tru64 UNIX Device Management

This section introduces the concepts required to understand devices in Tru64 UNIX. For the most part, Tru64 UNIX is similar to other UNIX flavors in some ways and very different in others. It is important to understand these similarities and differences so that a thorough coverage of the file systems is possible. We will begin rather generically with an overview of device management, but our end goal is to get into an in-depth discussion of the management of disk devices, since those are the devices used in the management of the file systems.

We will be discussing only the Version 5.0 device naming and structure here. Beginning with 5.0, Tru64 UNIX device management was changed dramatically not only from the user's perspective (since the naming scheme changed), but also in the kernel. There were two main reasons why changes needed to be made. First, they are required to enable TruCluster 5.x Single System Image (SSI), which means that disk and tape devices are seen consistently across the entire cluster. Second, the changes were needed to allow SCSI Wide Device and Fibrechannel support. In order to support these new requirements, the old device-naming scheme had to be changed.