bitkeeper, the 2_4_devel tree, and branches

My naive assumption, looking at the changesets listed at
http://ppc.bkbits.net:8080/linuxppc_2_4_devel/
was that if I cloned the repository as of two adjacent changesets, and exported from those repositories, the result would differ by exactly the second changeset.

That's probably true at some level, but when I tried it with the two tags 1.899 and v2.4.18 (aka 1.2.2.131), which are adjacent in the changeset list on that web page, I got two entirely different trees. It seems many branches exist in the linuxppc_2_4_devel tree, and that bk names branches using the godawful SCCS/CVS branch naming scheme. (Hrmf- after getting used to Perforce's branch naming, it's hard to go back to the branch-name-is-suffix-on-version-number-of-each-file way of life.)

Bitkeeper's doc is a bit thin on branches; for instance,
http://www.bitkeeper.com/manpages/bk-terms-1.html doesn't have a definition for 'branch'.

So it seems that, unless one knows what one is doing, one should avoid any revisions with more than one dot in their name, and one should shun the tags 'v2.4.xx', which are probably just mirrors of the Linus kernels.

Can someone confirm this, say a couple words on the use of branches in the 2_4_devel tree, and explain how the v2.4.xx tags are useful to linux ppc kernel hackers? Thanks!
- Dan

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

As a followup:

I saved
http://ppc.bkbits.net:8080/linuxppc_2_4_devel/ChangeSet@-1y?nav=index.html
as text in netscape, then ran it through

    grep -i ' 1\.[0-9]* .*Merge to 2.4'

to figure out which revisions with only one dot in their changeset name roughly corresponded to Linus kernels. Result:

10 weeks paulus 1.909 merge to 2.4.19-pre3 pulled from
linux_2_4 tree

  4 months  paulus      1.827    merge to 2.4.18-pre7
  5 months  paulus      1.796    merge to 2.4.18-pre2
  6 months  paulus      1.749    merge to 2.4.17-pre6
  7 months  paulus      1.654    merge to 2.4.15-pre5
  7 months  paulus      1.625    merge to 2.4.15-pre3
  7 months  trini       1.611    Merge to 2.4.15-pre1.
  9 months  paulus      1.468    merge to 2.4.10-pre11
  9 months  paulus      1.464    merge to 2.4.10-pre10
  9 months  paulus      1.456    merge to 2.4.10-pre9
  9 months  paulus      1.442    merge to 2.4.10-pre8
  9 months  paulus      1.440    new version of radeon driver, merge to
2.4.10-pre7
  9 months  paulus      1.439    merge to 2.4.10-pre7
  9 months  paulus      1.380    merge to 2.4.10-pre1
 10 months  paulus      1.294    merge to 2.4.9-pre1
 10 months  trini       1.257    Merge to 2.4.8-pre1
 11 months  paulus      1.209    merge to 2.4.7-pre5

This might be useful info for someone using the main branch of linux_2_4 and who needs a bugfix that was introduced with a particular Linus kernel, I suppose.
- Dan

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/