Yard is a suite of Perl scripts for creating a so-called rescue disk (a single floppy disk comprising a kernel and a filesystem with useful rescue programs). Rescue disks are used when you can't (or don't want to) boot off your hard disk; they usually contain utilities for diagnosing and manipulating hard disks and filesystems. The Linux doc file Bootdisk-HOWTO contains much information about emergency bootdisks and how to make them.
Most Linux distributions (eg, Slackware) come with some kind of pre-fabricated rescue disk. These disks contain a fixed set of utilities that are useful but may not be enough in an emergency. For example, if you want to restore files off of backup tapes you'll need a restore program that matches your backup program. It's desirable to have a complete, self-contained set of up-to-date utilities and kernel. You don't want to discover after a disk crash that, for example, your floppy tape driver is newer than the rescue disk kernel and won't work.
Yard lets you specify a set of files to be included on the rescue disk. Yard's specifications are flexible. The primary feature of Yard is that it does some checking of your choices to make sure that the rescue disk will be usable. Yard checks for basic mistakes that I found myself making repeatedly: missing/unlinked libraries, unresolved symbolic links, typos, etc. These mistakes are tedious to search for and many of them can be detected automatically, which is why I wrote Yard.
Yard comprises three Perl scripts: make_root_fs,
check_root_fs and write_rescue_disk.
These scripts are designed to be run in sequence. They are separate
so you can verify the output of one before going on to the next.
Typically you iterate making and checking the root filesystem a few
times before you write the rescue disk.