lkml.org 
[lkml]   [1998]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: bzip2 compression of kernel or initial ramdisk?
On Fri, 29 May 1998, Adam J. Richter wrote:
> I am not sure what is meant by "gzip can be used in place."

With gzip, you can malloc a piece of memory the size of the uncompressed image
and load the compressed image there. You don't need to do
malloc(uncompressed_size) and malloc(compressed_size).

> It appears that a bzip2'ed initial ramdisk and kernel would
> probably be worth doing for many circumstances, but, as measured by
> boot floppy kilobytes saved per programmer hour invested, it will
> probably be more effective to exhaust the following avenues first:
>
> 1. recheck for kernel options that are not useful in a fully
> modularized configuration
> 2. modularize the few remaining drivers that do not need to
> be on an initial boot floppy,
> 3. attempt to reduce module duplication between the main
> kernel distribution and the PCMCIA drivers,
> 4. more carefully strip kernels from module .o files and
> the pruned shared glibc built into the ramdisk,
> 5. investigate getting better compression by extending the
> window sizes in gzip beyond what gzip -9 provides. This
> will probably require using a different format change
> changes some 16 bit numbers to 24 or 32 bit numbers.
> 6. combine some duplicative code within the kernel image, probably
> starting with multiple copies of the decompression code.

7. Write a GPLed implementation of Open Firmware (IEEE P1275) that fits in
640 KB [1] and switches the CPU to `32-bit' [2] mode. Then you have a real
powerful boot monitor and are no longer plagued by the stupid 640 KB limit
that's so characteristic for the ia32 flavor of Linux.
And LILO becomes a simple portable FORTH script :-)

[1] Can't be a problem. The OF in my PPC easily fits in a 512 KB Flash ROM.
[2] I always forget whether it's called `real' or `protected' mode. IMHO real
life is 32 or 64 bit flat :-)

Greetings,

Geert

--
Geert Uytterhoeven Geert.Uytterhoeven@cs.kuleuven.ac.be
Wavelets, Linux/{m68k~Amiga,PPC~CHRP} http://www.cs.kuleuven.ac.be/~geert/
Department of Computer Science -- Katholieke Universiteit Leuven -- Belgium


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu

\
 
 \ /
  Last update: 2005-03-22 13:42    [W:0.181 / U:0.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site