Baslinux mailing list

[sindi keesan <keesan AT sdf.lonestar.org>]

On Thu, 19 Jan 2006, David Moberg wrote:

> sindi keesan wrote:
>
> > > > > I've uploaded it. By changing CFLAGS to -Os (in the makefiles) I
> > > > > was able to reduce the size by about 30k after compression.
> >
> > Please provide the URL.
>
> It is still at the same location. You apparently found it
> anyway.

I looked through a lot of old emails.  Do you mind if I link your BL 
download site to my site?  I know you have a varying set of files there.

> > I thought larger code ran faster (or loaded faster).
>
> No, twice as much code usually takes twice as long to
> execute. But sometimes a faster algorithm will be slightly
> larger than a slower one because of design choices.
> For example, using a lookup table (list of numbers) for
> computation will take more memory but will also be
> much faster than calculating every single problem.
>
> > If -Os optimizes for both size and speed, why use -02 as default?
>
> Inertia. -O2 is the traditional switch, and since so many programs
> used it in the past (before -Os became available) it is still often
> the default.
>
> MPlayer uses -O4 for some reason. Perhaps they feel that a couple
> K will not make a difference in a multi-megabyte binary.

-O4 optimizes for speed, right?  So  the only reason not to use it is if 
you want smaller executables?

> > With ordinary libraries (not uClibc) do faster executables get larger?
>
> Not noticeably or consistently.
>
> > They have in addition to the root-fs files, some tar.bz2 files
> > uClibc-0.9.28.tar.bz2 etc., about 1.7MB.  Are these source code and the
> > root_fs precompiled image?
>
> Yes, exactly.

> The root_fs includes binaries of gcc, binutils, bash, busybox, and lots
> more. The source code is just uClibc.

> > > To use the rootfs image, you need a partition with several hundred
> > > MB of disk space to grow into. bunzip2 it, then mount -o loop.
> > I am thinking about adding a 9GB scsi drive to one computer.
> > Does this 21MB expand to several 100MB?
>
> It expands to more than 100M. But you also need room to unpack
> whatever you are compiling.

So this 21MB image gets mounted to loop and then copied to a large 
directory (or another partition) and includes uclibc library, gcc, 
binutils, bash, and busybox.  I presume after copying it to that directory 
I also copy the source code to that directory before I chroot there and 
then compile it and it ignores any other libc on the computer.

> > If I am in a directory /uClibc does it use uClibc's root_fs libc and
> > binutils and gcc instead of the other ones on my computer?
>
> Yes, if you chroot to that directory. Just like chrooting between
> BL2 and BL3. The uClibc root_fs is essentially a kernel-less
> operating system that you can chroot into.
>
> > I think you are overestimating my understanding of linux.
>
> Maybe, but I don't think there is much that can go wrong.

Want to bet on it?  I will also need to either find precompiled, or 
compile from source code, various dependencies such as ncurses, or 
libjpeg, etc., or use ones compiled statically with glibc which I think 
would make them larger.  Where do I find precompiled libraries?

I hope the instructions tell you how to compile statically or dynamically. 
Is this a switch when you ./configure, with dynamic as default? 
For static ./configure --with-uclibc --with-ncurses  etc.?
For lynx I think I had some configuration file for configure.

> David