Adventures in old Kernels

I have started this post to describe some of the findings I made while playing around with building old Kernels....i.e. in the range 2.0.20 -> 2.0.40

This is all on the i386 architecture

The general process is....

keep you .config files somewhere safe.

install kernel source to /usr/src/linux
make sym-links from /usr/include/linux and /usr/include/asm

make distclean
[optional]copy in an existing .config file if desired
make menuconfig
make dep ; make clean
make
make zImage

Not that long ago (ok, I am OLD, so for you it might seem long ago) I recall compiling my own 2.2 and 2.4 kernels when those were new. I had somewhat unusual hardware, and wanted better performance, and it worked.

I occasionally use DSL, and it uses as older kernel to fit into a smaller space with pretty good performance. I have not had to compile my own kernel in years. As I recall, the kernel source downloads came with documentation on requirements and steps to succeed.

The only thing that I would add to your procedure is:

(1) Make a duplicate, non-hidden copy of the hidden configuration file, and put it in a protected subdirectory of (say ...) /root. Make this file read-only. Pick a file-name that is distinctive, including date, version-number and so on, 'cuz you're gonna keep this file forever.

(2) Rename the hidden file out of the way. Then, run make distclean, which ordinarily would wipe out that file. Then, rename it back. Now, you can be sure that subsequent make steps will, indeed, recompile everything. (It does not take long ...)

If you are very disciplined to keep every config file ... even those that didn't work as you wanted them to(!) ... and if you also maintain a "Captain's Log, Stardate 1234.5" with that same self-discipline, then you can use diff to identify the complete set of changes between any configuration and any other. You can also revert to any previous configuration with absolute accuracy.

(I also know of some folks, with many different systems to maintain, who copy into a single backup-file per system, but they've set up the directory as a git repo, allowing them to do version control on the configurations. Another very good way to do it.)

yes the point about protecting the config and doing a make distclean is an important one.

Originally Posted by sundialsvcs The only thing that I would add to your procedure is: ... (2) Rename the hidden file out of the way. Then, run make distclean, which ordinarily would wipe out that file. Then, rename it back. Now, you can be sure that subsequent make steps will, indeed, recompile everything. (It does not take long ...)

Something I have tried is the following (for i386 architecture).

Create a vmlinux on one machine and create the zImage wrapper around it using another:

Take your copy of vmlinux(created on machine A) and on machine B, place it in /usr/src/linux as vm_other

On machine B do the following:

in /usr/src/linux/arch/i386/boot/Makefile

Change:
compressed/vmlinux: $(TOPDIR)/vmlinux
@$(MAKE) -C compressed vmlinux

To:
compressed/vmlinux: $(TOPDIR)/vm_other
@$(MAKE) -C compressed vm_other


in /usr/src/linux/arch/i386/boot/compressed/Makefile

Change:
SYSTEM = $(TOPDIR)/vmlinux

To:
SYSTEM = $(TOPDIR)/vm_other


Change:
vmlinux: piggy.o $(OBJECTS)
$(LD) $(ZLINKFLAGS) -o vmlinux $(OBJECTS) piggy.o

To:
vm_other: piggy.o $(OBJECTS)
$(LD) $(ZLINKFLAGS) -o vmlinux $(OBJECTS) piggy.o

go into /usr/src/linux and do make zImage, hey presto..... the zImage will get built using the vm_other