Prior to A/UX 3.0 when a "newconfig" command is used to build a new kernel,
the file "/newunix" is used as the base for the new kernel. Therefore, the
new kernel (/unix) parameter values, like NBUF, NINODE, NFILE, and so on,
will be reset to the default from /newunix. To keep the current kernel
parameter values when the new kernel is built, use this:
# cp /newunix /newunix.orig #! Save the original newunix
# kconfig -n /unix #! Modify kernel parameters
# cp /unix /newunix #! Copy the current kernel to newunix
# newconfig #! reconfig the new kernel
The new kernel will be built with the current kernel parameters.
If you want to build a new kernel based on the original, the /newunix.orig
can be copied back any time. For example, cp /newunix.orig /newunix.
With A/UX 3.0 and higher, the above process is not necessary because the
parameter values, like NBUF, NINODE, NFILE, and so on, are kept and become
part of the new kernel.
If there is new hardware (like an EtherTalk NB Card) to be added to the
system, A/UX will automatically configure it when A/UX is started up. The
file "/newunix" is also used as the base for the new kernel.
Here is a description of booting/launching decision:
When A/UX Startup is launched, by default, it performs:
* AutoRecovery, which checks the root file system with the command:
/dev/default
If the file system check is successful, do:
* AutoLaunch with the command: launch
The launch command first checks the default kernel against the hardware.
Because no kernel is specified on the command line, the contents of file
/nextunix, which is /unix, is used by launch. If the kernel matches the
hardware, the /unix kernel is used to start up A/UX. If the kernel doesn't
match the hardware, the launch command uses the /newunix kernel instead to
build the new kernel, and the new kernel is placed on /unix.
Article Change History:
18 Aug 1993 - Updated to include A/UX 3.x, and reviewed for technical
accuracy.