Knowledge Base

Any of these problems can occur if you recently updated your Linux host's 2.4 series kernel to a 2.6 series kernel, and a virtual machine on that host is configured with an IDE physical disk (sometimes called a raw disk). The 2.6 series kernel determines the disk geometry differently than a 2.4 series kernel does. As a result, the physical disk cannot boot, may hang or may return an "Attempt to execute undefined memory" error, depending on the operating system installed on the physical disk.

Note: VMware does not support host kernels in the 2.6 series.

To work around this issue, you need to pass the 2.4.x kernel disk geometry as a boot option when you boot your 2.6.x kernel.

To derive the 2.4.x kernel disk geometry, boot your 2.4.x kernel, and run the following command:
hdparm -g /dev/hda

Write down the disk geometry obtained from the command, then supply that geometry when you boot the 2.6.x kernel.

For example, if the hdparm -g command reports:
geometry = 14593/255/63, sectors = 234441648, start = 0

Then you should use the hda=14593,255,63 option when you boot your 2.6.x kernel.