http://www.balloonboard.org/balloonwiki/BalloonDevelopment#Downloads_directory

The menuconfig2 branch now supports retaining selected tarballs for
easier rebuilds. The downloads directory is not managed automatically,
any tarballs you want to retain for future builds need to be copied out
of the relevant build directory and into downloads. Copies of the linux
kernel sources, yaffs sources and buildroot sources will be located by
the build if the relevant version exists in downloads/. The tarballs
which buildroot itself normally downloads for it's own build can also
be retained and re-used, those tarballs go into a downloads/dl
directory (which needs to be created if you are using this bit of the
support).

Something like:
cp -v -f build/buildroot/buildroot-*.tar.* ./downloads/
cp -v -f build/kernel/linux-*.tar.* ./downloads/
cp -v -f build/kernel/yaffs*.tar.* ./downloads/
mkdir -p ./downloads/dl/
cp -v -f build/buildroot/buildroot-*/dl/* ./downloads/dl/

Any change in the build configuration which causes a change in the
version of any other the tarballs required will cause that version to
be downloaded and you would need to copy it into downloads to be
re-used.

The downloads directory is never cleaned out, it is up to individual
maintainers to monitor the directory for unnecessary files. 

......................

e.g. a sample build gave:
       0  ./downloads/
       0  ./downloads/dl/
 1064281  ./downloads/dl/mpfr-2.4.1.tar.bz2
  907411  ./downloads/dl/gzip-1.4.tar.gz
  328134  ./downloads/dl/mtd-utils-1.4.1.tar.bz2
70236745  ./downloads/dl/linux-2.6.36.1.tar.bz2
    9338  ./downloads/dl/liblockfile_1.08-4.debian.tar.bz2
  137270  ./downloads/dl/lockfile-progs_0.1.15.tar.gz
  395829  ./downloads/dl/fakeroot_1.9.5.tar.gz
    8764  ./downloads/dl/usbmount_0.0.14.1.tar.gz
  841402  ./downloads/dl/bzip2-1.0.5.tar.gz
 2093389  ./downloads/dl/busybox-1.17.4.tar.bz2
  280938  ./downloads/dl/lrzsz-0.12.20.tar.gz
  486374  ./downloads/dl/zlib-1.2.5.tar.bz2
  198912  ./downloads/dl/udev-114.tar.bz2
 2297174  ./downloads/dl/uClibc-0.9.31.tar.bz2
   30236  ./downloads/dl/liblockfile_1.08.orig.tar.gz
  398872  ./downloads/dl/netcat-0.7.1.tar.gz
59347925  ./downloads/dl/gcc-4.3.5.tar.bz2
  269432  ./downloads/dl/kexec-tools-2.0.1.tar.bz2
 1710660  ./downloads/dl/gmp-4.2.4.tar.bz2
  808352  ./downloads/dl/lighttpd-1.4.28.tar.gz
17591527  ./downloads/dl/binutils-2.20.1.tar.bz2
 2763164  ./downloads/buildroot-2010.11.tar.bz2
       0  ./downloads/
76097195  ./downloads/linux-2.6.39.4.tar.bz2
  208844  ./downloads/yaffs-2011-02-09.tar.bz2

The purpose of this directory is to make it possible to also support
snapshotting a complete balloonboard build so that, at any later date,
the exact build can be repeated with all of the same methods, patches,
sources and configuration. e.g. it is now reasonably trivial to start
with a clean checkout, make whatever configuration is required, copy
out the .config to somewhere safe, run the build, copy out the
downloaded tarballs and sources, keep them safe, do an svn export of
the menuconfig2 branch at the time you did the build and tar up the
whole thing. (Only compress the SVN checkout, just tar the rest.)

I'm also preparing support which will allow the repositories accessed
by multistrap to be copied but these are much larger chunks of data and
it is often easier to include the *result* of the multistrap build into
the snapshot, as long as the config is set to not rebuild the rootfs.

-- 


Neil Williams
=============
http://www.linux.codehelp.co.uk/