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Re: Converting ClearCase to CVS

From: Mark
Subject: Re: Converting ClearCase to CVS
Date: Fri, 15 Feb 2002 05:45:21 -0800 (PST)

--- "Mark A. Flacy" <address@hidden> wrote:
> Out of curiosity, why are you moving from ClearCase to CVS?

Okay, you asked. Here it comes. But my question would be why not move from
ClearCase to CVS? This comes from my personal experience at multiple clients,
some using CVS, some CC, some both. 

ClearCase has:

- much large cost of tool and support (I think their in kohuts with $Oracle$
and that they are learning software development and customer relations from
- much more money to shell out if you need to work at different locations
without depending "always on" conection over a network, to simulate the
unwritten rule that the client and server need to be (logically) on the same
machine to work. (even if you use multisite, you get to the added benefit of
needing merge everything on each end, which kills most if not all benefit of
multisite if both sites need to work on the same release/branch)
- a much larger "tool admin" to "project/user" ratio. Are you spending more
time on CM activities or babysitting the tool? Does you phone ring for CM
issues or CC issues? Do your users that just want to checkin their work without
needing a PhD from $Rational University$ 
- cannot handle interopability, yes Virginia, you must purchase or obtain yet
another tool to assist CC, and add that to your overhead activities to maintain
this tool to compensate/help out CC. (how much did you spend on CC and how much
is it still costing you per day?)
- much more larger (and persistent) learning curve (and ongoing user
frustration level, especially if the out-of-touch high level people that where
sold the tool where also sold on UCM, the so called "out-of-the-box" solution)
- no additional functional benefit do to "directory versioning", cvs add/remove
per branch per file is suffiently equivalent/reasonable. (continue reading if
you want to reply to this one about renames and moves) don't get me wrong, I
think directory version is great, but its importance in the grand scheme of
things is artificially inflated.
- cost/amount of infrastructure that is needed, CPU/bandwith/servers. Its
expensive to keep performance up. contrary to what you may find on CCUIG,
clearcase is anything but efficient when it comes to disk space. You have the
VOB and all versions, fine, but the VOB also has cache it maintains to send
files to views and you must regularly free it up to get back disk space. Views
do not save on disk space, beacuse to use a file, it must be _copied_ into the
view (just like CVS). but views have an added benefit, they can collect and
store deltas in a cache for more that one version of the file, that must be
cleaned up to get back disk space. Oh, you need to update a few files in you
view, CC needs to continuously export a file system over the network to each
client, CVS just sends packets with just the deltas needed, when needed. CC
functionaly does what CVS does for updating views/workarea, CC just needs a lot
more of everything (CPU/bandwith/diskspace) to do it and does it at a different
time (at file use or checkout vs workarea creation). So if you never use or
view a file in a CC view or have a bunch of garbage in your repostory you will
never use in a build or development, then CC can be more efficient. How about
all those processes CC has up and running, dragging down the system, just
waiting around to be used (or begging to be restarted/bounced).
- Trigger processing on the client, and all the maintenance fun that goes with
it <yuck>. why can't you have integration prcoess ing done on the server and
have a web based tracking tool and not worry about users client machine setup
and configuration? well now we can.
- lousy vendor support, yes the CCUIG keeps rational in business, without it I
think rational would be out of business.

Okay, the way Clearcase stores elements is neat (hey, its a relational
database), you can rename a element (the name is just metadata, like a
tag/label is) and even track an elements movement around a repository (more
data for the database). What's the value added benefit? When was the last time
someone asked where a file was in the repository 5 months ago? Or, has this
file had a different name before? Is the total cost to your business, by doing
business with rational, worth being able to answer these silly questions?

Then only thing going for ClearCase is merge tracking (UCM sure knows about
this), that is really an asset. but coordinating merging in CVS isn't that bad.
But if you branch for every silly thing, well... can't help that, we have a one
to one relationship between branches and product releases, merging is minimal.
Is all about planning, and ounce of CVS is worth a pound of CC.

UCM - this is not a process, it is not CM, it is called change sets, its a tool
function that has been implemented in the most convoluted way (adding a whole
new command set and abstraction to protect you from you, I guess). Normally you
connect to a tracking tool and tie file versions to a ticket/bug number
whatever, for change sets. Why did they do UCM in ClearCase? don't know. Maybe
they never learned the rule, "if it ain't broke don't fix it". Maybe they
realized their bloated software does anything but work "out of the box", and
making UCM is needed to hold people over till the army of CC/CQ admins, SAs and
DBAs, can get things working right. But don't think about upgrading Oracle from
8.1.34 to 8.1.35 cause your CQ is at 2001 and only 2001a can handle Oralce
8.1.35. Oh, you need CQ 2001a, well that may not work with CC 4.1, you now need
to upgrade to CC4.2. yadda yadda yadda. Okay previous versions where examples,
but you get the picture? Rational must not know much about backward
compatibility, OOD, where's RUP when you need it Rational?

Unless your a CMM level 5 company, writing software that affects lives, spend
more time writting/following process than producing code, Rational tools, may
actually be counter productive to your company. The ROI is not in sight and the
gap is widening. Cutting loses and movin on. May need to re-image PCs to fully
recover from rational. :)

I used to compensate/cover for rational like other CC proponents, but Rational
folks rubbed me the wrong way one to many times, now I call it like I see it.
Okay, more of a rant, but does this answer your question?


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