This is an archive of past FreeBSD releases; it's part of the FreeBSD Documentation Archive.
Not at all! Check out the kernel config section of the Handbook.
Note: The new kernel will be installed to the /boot/kernel directory along with its modules, while the old kernel and its modules will be moved to the /boot/kernel.old directory, so if you make a mistake the next time you play with your configuration you can boot the previous version of your kernel.
You probably removed npx0 (see npx(4)) from your kernel configuration file because you do not have a math co-processor. The npx0 device is MANDATORY. Somewhere inside your hardware lies a device that provides hardware floating-point support, even if it is no longer a separate device as used in the good old 386 days. You must include the npx0 device. Even if you manage to build a kernel without npx0 support, it will not boot anyway.
Chances are, you compiled your kernel in debug mode. Kernels built in debug mode contain many symbols that are used for debugging, thus greatly increasing the size of the kernel. Note that there will be little or no performance decrease from running a debug kernel, and it is useful to keep one around in case of a system panic.
However, if you are running low on disk space, or you simply do not want to run a debug kernel, make sure that both of the following are true:
You do not have a line in your kernel configuration file that reads:
You are not running config(8) with the
Either of the above settings will cause your kernel to be built in debug mode. As long as you make sure you follow the steps above, you can build your kernel normally, and you should notice a fairly large size decrease; most kernels tend to be around 1.5 MB to 2 MB.
When I compile a kernel with multi-port serial code, it tells me that only the first port is probed and the rest skipped due to interrupt conflicts. How do I fix this?
The problem here is that FreeBSD has code built-in to keep the kernel from getting trashed due to hardware or software conflicts. The way to fix this is to leave out the IRQ settings on all but one port. Here is an example:
# # Multiport high-speed serial line - 16550 UARTS # device sio2 at isa? port 0x2a0 tty irq 5 flags 0x501 vector siointr device sio3 at isa? port 0x2a8 tty flags 0x501 vector siointr device sio4 at isa? port 0x2b0 tty flags 0x501 vector siointr device sio5 at isa? port 0x2b8 tty flags 0x501 vector siointr
There are a number of possible causes for this problem. They are, in no particular order:
You are not using the make buildkernel and make installkernel targets, and your source tree is different from the one used to build the currently running system (e.g., you are compiling 8.2-RELEASE on a 7.4-RELEASE system). If you are attempting an upgrade, please read the /usr/src/UPDATING file, paying particular attention to the “COMMON ITEMS” section at the end.
You are using the make buildkernel and make installkernel targets, but you failed to assert the completion of the make buildworld target. The make buildkernel target relies on files generated by the make buildworld target to complete its job correctly.
Even if you are trying to build FreeBSD-STABLE, it is possible that you fetched the source tree at a time when it was either being modified, or broken for other reasons; only releases are absolutely guaranteed to be buildable, although FreeBSD-STABLE builds fine the majority of the time. If you have not already done so, try re-fetching the source tree and see if the problem goes away. Try using a different server in case the one you are using is having problems.
Check for the existence of the
sysctl. If you have it, you should see something like this:
% sysctl kern.sched.quantum kern.sched.quantum: 99960
% sysctl kern.sched.quantum sysctl: unknown oid 'kern.sched.quantum'
The name of the scheduler currently being used is directly available as the value of
% sysctl kern.sched.name kern.sched.name: 4BSD