[Axiom-developer] Arch, Darcs, Subversion, or CVS again

[Bill Page]

On Tuesday, February 15, 2005 11:41 PM Tim Daly wrote:
>
> On Tuesday, February 15, 2005 10:18 PM Mike Thomas wrote:
> > Gratuitous Complaint Time (apologies in advance) -  I
> > have yet to either successfully use the sftp repository
> > or download a tree over a modem.  Arch has also left me
> > with vast directory trees I could not delete except by
> > shortening the directory names down the tree first and has
> > done bizarre permission mangling on files so they were
> > editable with wordpad but not with emacs!  Arch on Windows
> > is an appalling program to use - I feel strongly disinclined
> > whenever I think about working on Axiom.

I have had MUCH better success using arch on Windows (same
version that Mike is using I think) but over a relatively high
speed connection (download only, upload is at slow modem speeds).
I have also had the problems of deleting arch directory trees
due to extremely long names and some odd permission settings
(under Windows XP only). Perhaps these problems are being
addressed by the developer or maybe we should submit a bug
report to him?

> ... 
> just so you're not alone i'm coming to believe that arch
> downloads 2 full copies of the source (one for the "pristine"
> version). I'm unhappy with this as I'm always working in the
> last 2% of my disk space so, unless i can figure out a way to
> prevent that, it may be the case that we abandon arch for
> something else (darcs? subversion?)
> 

First thing: Tim, go out and buy yourself a few 100 Gb. drives
for $25 or so! :)

Second, I agree with you about arch's gluttonous demands for
disk space - and also with Mike's previous implied complaint
about it's demands for high speed network access.

Part of the problem here is just in the way we are currently
using arch, i.e. in the "centralized file-pull" mode where
there is an "old-fashioned" CVS-style central repository. Arch
can also be used in the newer "file-push" mode (like darcs)
where everyone maintains there own local copy of the archive
and changes are pushed (usually by email) to other developers.
Usually one or more developers also take the role of maintaining
an "official version" from which copies are made.

Also, from following the arch mailing list I have learnt that
it is possible to set up a "revision-library" which is much more
efficient for remote access than the way arch does things by
default. These things are described in the arch documentation
but as far as I know there are no simple tutorials that give
an easy recipe for this.

Martin Rubey here on this list has also had some experience with
improving arch performance and moving repositories by CD rom
instead of modem.

About darcs: Compared to arch, it seems to me that darcs is MUCH
more efficient in the way it saves the diffs. Of course in
terms of features it is also much more "light weight" than arch,
but I think it could be easily used to do the same thing that
we do now with arch - except as I mentioned above, darcs uses
a file-push model only. In the case of darcs there is no central
repository where everything is stored. In short, I am strongly
in favour of experimenting with darcs for the Axiom archives but
I think we will have to learn a slightly different way of
maintaining the archives.

Although subversion has been adopted by some other open source
projects, my impression after a first look at it is that is would
be a step backwards (toward the old CVS-style archive). I think
it is appealing for those people who really only want a better
CVS.

Regards,
Bill Page.