The ``build on boot'' feature allows you to perform several installations and/or other modifications to the kernel, and later, execute a single rebuild of the kernel. It cleanly separates the build process from the installation, removal, and modification processes. The build-on-boot process is done automatically on shutdown to system state 5 (the firmware state) or system state 6 (the stop and reboot state). Otherwise, it is done automatically when the system next comes up.
For example, when you install a new software package, or new hardware that needs to be configured into the operating system, the installation scripts provided with it will probably invoke /etc/conf/bin/idbuild without any options after installation. This sets a flag and exits without actually rebuilding the kernel. The system displays the following message when this occurs:
The unix kernel will be rebuilt to include your configuration changes during the next system reboot.
Later, when you reboot or shut down the system using the init or shutdown commands, the system checks the flag; if the flag is set, the system invokes idbuild to rebuild the kernel. The following example shows a typical interaction with the booting process:
UX: shutdown: INFO: Shutdown started. Mon Sep 26 20:40:34 EDT 1994When you press the <ENTER> key, the kernel is rebuilt, the new kernel is installed as /stand/unix, and the original kernel is saved as /stand/unix.old. If an error occurs during the kernel rebuild, an error message is mailed to root and also displayed on the console.
Do you want to continue? (y or n): enter y to continue # #UX: init: INFO: New run level: 0 UX: /sbin/rc0: INFO: The system is coming down. Please wait. UX: K00ANNOUNCE: INFO: System services are now being stopped.
Press any key to reboot ... you respond by pressing <ENTER> . . the UnixWare logo screen appears briefly during this time . The system is coming up. Please wait. . . . UX: idbuild: INFO: The unix kernel will be rebuilt now. This will take some time. Please wait.
If the kernel is built as the system is on the way up after a reboot, the system shuts down again, after the build is complete, then automatically reboots with the new kernel.