Hello The url above is a kernel for The JOS Project (www.jos.org). There is a problem in which the above kernel it can't be compiled using Redhat 5.2, it work's with Redhat 5.0 and Caldera 1.1 (after upgrading binutils). This is the output of 'make all' on Redhat 5.2: $ make all gcc -Wall -O2 -I ./include -c boot.s gcc -Wall -O2 -I ./include -c start.s start.s: Assembler messages: start.s:17: Error: Value of -65472 too large for field of 2 bytes at 9 start.s:18: Error: Value of -65432 too large for field of 2 bytes at 14 make: *** [all] Error 1 The two lines giving the error are: lgdt (gdtr - kaddress) lidt (idtr - kaddress) The output for 'as -al start.s' for Redhat 5.2 and Redhat 5.0 is below, as you can see the wrong opcodes are being produced. Redhat 5.2 17 ???? 0F011640 lgdt (gdtr - kaddress) 17 00 18 ???? 0F011E68 lidt (idtr - kaddress) 18 00 Redhat 5.0 17 0006 670F0115 lgdt (gdtr - kaddress) 17 4800FFFF 18 000e 670F011D lidt (idtr - kaddress) 18 7000FFFF After getting down binutils-2.9.1.tar.gz from metalab.unc.edu/pub/gnu and installing, I was able to compile the above kernel. Robert Fitzsimons robfitz