Re: [Monotone-devel] newbie question - SHA1 vs serials

[Richard Levitte - VMS Whacker]

In message <address@hidden> on Tue, 19 Apr 2005 07:40:06 -0700, "K. Richard 
Pixley" <address@hidden> said:

rich> Why SHA1 instead of serials?

You came to the answer yourself :-) (globally unique, or at least
close enough).

rich> To provide globally unique serials, one would need to include
rich> some representation of the location at which an event occurred.
rich> In this case, I'd suggest the domain name of the machine
rich> involved.  So something like 1:monotone.venge.com,
rich> 2:monotone.venge.com, etc.  If each repository used it's own
rich> name, (presumably it's domain name in most cases), and kept it's
rich> own list of serials, wouldn't this both provide a guaranteed
rich> unique id ?

I assume you've understood that it's really one repository per
development machine, right?  The database is basically replicated all
over the place.  So a domain name (as opposed to host name) may not be
enough, and in some cases, maybe not even a FQDN.  We might end up
with n:address@hidden or something like that.  Then the
question is, what happens when someone changes email address and wants
all those serials to refer to the new email address (because for sure,
others will use the email address part of the serial number to
communicate with the author of that particular revision)?

rich> as well as providing that oh-so-sought-after monotonically
rich> increasing number people so love to see

Quite honestly, I don't believe the love for those monotonically
increasing numbers is that strong.  I thought so too when I started
using monotone, but I find that the unique features in monotone
strongly overweigh the increasingly small pain of dealing with SHA-1
checksums.

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Richard Levitte                         address@hidden
                                        http://richard.levitte.org/

"When I became a man I put away childish things, including
 the fear of childishness and the desire to be very grown up."
                                                -- C.S. Lewis