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Our experts answer your technical questions.
Setting Up Linux to use Two Processors

I just upgraded to a dual Pentium Pro machine. The BIOS sees the two processors but I can't tell if Linux (Kernel 2.0.27) uses both processors. How do I make Linux use its SMP features?

—Jon Bishop Red Hat 4.1

To take advantage of SMP you'll need to recompile your kernel to use both processors. First make sure the kernel-source RPM is installed. Then go to /usr/src/linux and edit the Makefile. You'll find a line that looks like:

# SMP = 1

Uncomment that line by removing the hash symbol. Then build a kernel as you normally would (see the Kernel HOWTO at for more information).

—Donnie Barnes, MIS Director Red Hat Software,

Signal 11 Error

When I try to compile a new kernel with custom specifications, the compile fails at approximately the mid-point, giving me an error message that reads:

gcc: internal compiler error 11.

Please tell me what this could mean.

—Joe Ortiz Slackware 2.0.30

It very likely has something to do with your hardware configuration. There is a web server dedicated to the signal 11 problem. Check out Hopefully the information there will solve your problem.

—Pierre Ficheux Lectre Systèmès

I have seen this happen on several machines. Every time the problem is a bad memory chip installed on the computer's motherboard. Signal 11 is the Segment Violation error which generally occurs when a program's pointers go awry.

gcc is a stable enough program that this should not occur during a simple compile, but it does use memory heavily, and Linux (or any Unix) is quite sensitive to bad memory.

It is also possible that a library file on your system is corrupt or incompatible with other libraries. If, however, this was the case, you should see problems in other programs as well. Library corruption should only happen if you have recently installed new libraries or modified your existing system libraries.

—Chad Robinson, Senior Systems Analyst BRT Technologies,

Mixing Linux and NT

How can I get Linux to install on a system along with WinNT? I have plenty of unpartitioned space available.

—Casey Woodrum Red Hat 4.2

The only trick with mixing Linux and NT is configuring the boot process. Linux will install as usual, but you may need to fix up the boot setup by hand once the installation is finished. Assume NT is on partition /dev/sda1 and you install Linux on partition /dev/sda2. Try to be sure your Linux partition is a primary partition on a cylinder less than 1024. This isn't necessary, but it simplifies things.

You should use Microsoft's master boot record instead of LILO. Do not install LILO onto the master boot record of the hard disk. NT will crash dump in most cases with LILO as the master boot record. With all this in mind, take the following steps:

1. Edit the /etc/lilo.conf file so that:


is the first line. Selecting /dev/sda2 as the target for LILO during installation should have done this for you.

2. Add an entry to boot NT at the end of lilo.conf:

other = /dev/sda1
label = nt

If the installation program is smart enough, you should be able to configure this during installation.

3. Run LILO to install the new lilo boot configuration.

4. Reboot into NT. Use FDISK under NT to mark partition 2 (/dev/sda2) as active. You should get LILO on reboot. From the LILO boot prompt, you can type nt to get the NT boot loader.

If the installation process doesn't configure LILO correctly, you may need to boot Linux from floppy and edit the files on the hard disk from floppy.

—Larry M. Augustin, VA Research

An undocumented FDISK parameter can help you out of tight spots if you create trouble on your disk. Run:

fdisk /mbr

to restore the master boot record on your boot drive. This will remove LILO, allowing you to use Windows NT if you somehow cause trouble during the installation process.

—Chad Robinson, Senior Systems Analyst BRT Technologies,