5.1 Boot Failures

A system that won't boot can be frustrating and difficult to troubleshoot. The troubleshooting tools that come with Tru64 UNIX require (not unreasonably) Tru64 UNIX to be up and running. The troubleshooting capabilities available at the console firmware level are much more limited in scope. In many cases, a trial-and-error approach is necessary to determine the cause of the problem. However, by approaching the problem systematically, it's usually possible to isolate the cause and begin correcting the problem.

In this section, we consider failures that happen when booting from a disk (including a CD-ROM) or a disk-based storage set (e.g., a RAID-5 set). Tru64 UNIX can also be booted over a network when using dataless management services (DMS) or from a bootable tape created with the btcreate(8) command. Neither of these last two options is commonly employed; the vast majority of boot problems occur when booting from disk.

In general terms, a system can fail to boot in four different ways:

1. It gets an error message and returns to the console prompt (i.e., it crashes during the boot sequence).

2. It loops trying to boot, then crashes, tries to boot again, etc.

3. It displays an endless series of error messages until interrupted.

4. It hangs at some point in the boot sequence and never continues.

Each of these situations is discussed individually, but first here are some general workarounds suitable for all boot problems.