[p4] ClearCase vs. Perforce
k73946 at retriever.dyndns.org
Fri Jun 8 15:24:41 PDT 2001
On Fri, Jun 08, 2001 at 01:11:37PM -0700, Karr, David wrote:
> I wasn't going to respond to this originally, because I don't consider
> myself an expert, but I can't believe some of the things you say here,
> without any data to back them up.
I don't know what you mean by 'data' but this is my experience.
> Version management in ClearCase is extremely powerful. Whether you're
> talking about the "version" of a system, or revisions of particular
> elements, there is a great deal of flexibility available. I wouldn't say
> this is easy to use out of the box, but if you design a development
> environment that facilitates this, you will have a great deal of power.
In the system I used, Clearcase didn't have the concept of a
change-list. The build was constantly broken because people
would only check-in 4 out of 5 files necessary for a fix. They
would subsequently do the same thing when merging the fix to
> The "version" of a system or the mapping to element revisions can be
> modified by changing a single file (configspec), and as ClearCase uses a
> file system driver to provide access to elements, after changing the
> configspec, it instantly changes the version mapping you see in your file
Isn't it true that when you change the config spec and the version
of a file mapped in changes, that the timestamp on the file goes
to when the file was checked in, not to when the config spec was
And isn't it true that every make in the world (except Clearmake
of course and, I suppose, makepp) will then fail to recognize
that the file needs recompilation ?
> Directories in ClearCase can be versioned, which is a feature missing in
> Perforce and CVS.
I for one haven't needed that feature yet.
> With respect to "build management", ClearCase certainly lets you "pick
> tools", juat as with Perforce. However, if you use their "make", which is
> an enhanced clone of GNU make
Clearmake is missing many features of gmake. It is NOT a drop-in
> ClearCase provides even more power, as it
> provides for the ability for "derived objects" (object files, libraries,
> executables, etc.) to be mapped to "config records", which describe exactly
> what versions of "dependent objects" were used to build those objects. This
> is done automatically, under the covers, by the ClearCase file system driver
> while watching file manipulations.
Unfortunate if he wants to use pmake or the like.
> With respect to "ease of use", I would certainly admit that with its large
> number of features, it has a high learning curve, and out of the box is
> probably difficult to use and administer. However, it's considerable
> flexibility allows CM engineers to build development environments that make
> it much easier to use. Even without that, the ClearCase GUI tools for
> viewing branch histories and for merging element revisions are much better
> than you can get OOTB with Perforce.
> In the last large ClearCase project I worked on, the ClearCase administrator
> left, because there was nothing left to do, and the system just didn't
In the last "large" Clearcase project I worked on, the
administrator (a Clearcase expert, supposedly) took 4 months to
set the system up and even after that was constantly running
from desk to desk helping people. Productivity was cut at least
> The cost of ClearCase vs. Perforce is certainly an important factor.
> However, I've only been using Perforce for a few months now, but I guess I'm
> not sure what the real value of Perforce over CVS is.
Speed, atomic transactions, change lists, better branching, keeping
track of already merged changes, ... There's no comparison.
My 2 cents,
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