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10 replies Latest Post - ‏2013-09-30T14:20:17Z by GKellner
Hamouda_screen
Hamouda_screen
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Pinned topic ClearCase vs GIT

‏2012-02-08T17:29:53Z |
Hello,

I would like to get information on Pro's & Con's of ClearCase Vs GIT,
any information would be appreciated.
Thanks

Hamouda LAYOUNI
Updated on 2012-02-10T12:23:03Z at 2012-02-10T12:23:03Z by SystemAdmin
  • SystemAdmin
    SystemAdmin
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    Re: ClearCase vs GIT

    ‏2012-02-08T18:13:28Z  in response to Hamouda_screen
    Git and ClearCase are really two different creatures.

    Git is very lightweight and focuses upon code checkin/out. There is very little enforcement and you can shoot both feet off with ease.

    ClearCase provides SCM functionality as well as workspace management, build avoidance, and both dynamic and snapshot modes of workspaces. ClearCase also has powerful branch and merge modes that Git does not support.
    ClearCase also supports branch promotion and just in time branching for you. Git does not and you have to be
    careful to handle those cases.

    I could go on for a few pages. Perhaps you could give us an idea of what your requirements are or what your development style is and we could provide more focused comparisons.

    Cheers
    • SystemAdmin
      SystemAdmin
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      Re: ClearCase vs GIT

      ‏2012-02-08T18:47:20Z  in response to SystemAdmin
      Bryan Miller wrote:
      > Git and ClearCase are really two different creatures.
      Right. Sure. Now, this is not very useful.
      Git was presented as a tool for 'source code archiving and distribution'.

      > Git is very lightweight and focuses upon code checkin/out.
      Not only. It focuses on change sets (in some acception of the term) and on performace, especially for the end user.

      > There is very little enforcement and you can shoot both feet off with ease.
      So? Is this a good or a bad thing?

      > ClearCase provides SCM functionality...
      Controversial: defined in verbose and contradictory ways.
      With a lot of alleged synonyms, marketing bullshit and loose ends (ALM, governance, etc...)

      > ... as well as workspace management, build avoidance,
      Some beef...

      > ...and both dynamic and snapshot modes of workspaces.
      Controversial interest... Dubious complexity.

      > ClearCase also has powerful branch and merge modes that Git does not support.
      No.

      > ClearCase also supports branch promotion and just in time branching for you.
      I see what you mean with the second, and Git fans won't value it.
      I have no clue what you mean with the first.
      Probably something with UCM? Very unlikely that there would be any honest value there.

      > Git does not and you have to be careful to handle those cases.
      Or happy to ignore them.

      Now, there is some potential in ClearCase that might make it compare favourably to Git.
      But it is not commonly known or used, and would require some support at last from IBM.

      Marc
      • SystemAdmin
        SystemAdmin
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        Re: ClearCase vs GIT

        ‏2012-02-08T18:58:20Z  in response to SystemAdmin
        Marc,

        Let's keep this discussion civil and as objective as possible.

        If you want to elaborate on your points with descriptions and examples that would be helpful. Name calling and tantrums will not add any clarity to the discussion and only discredits your perspective.

        Cheers
      • SystemAdmin
        SystemAdmin
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        Re: ClearCase vs GIT

        ‏2012-02-08T19:03:55Z  in response to SystemAdmin
        I am currently using both Git (on Linux) and ClearCase (on HP-UX) and find them quite different.

        I would be interested in hearing why you don't think that is true.
        • SystemAdmin
          SystemAdmin
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          Re: ClearCase vs GIT

          ‏2012-02-09T12:44:38Z  in response to SystemAdmin
          docMiller wrote:
          > I am currently using both Git (on Linux) and ClearCase (on HP-UX) and find them quite different.
          >
          > I would be interested in hearing why you don't think that is true.
          I find this true.
          And wrote it already once.
          Marc
  • SystemAdmin
    SystemAdmin
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    Re: ClearCase vs GIT

    ‏2012-02-09T18:52:38Z  in response to Hamouda_screen
    Hello Hamouda,

    One difference between ClearCase (and I am referring to Base ClearCase here) and Git is that ClearCase provides dynamic views. That means that you don't need to copy all of your source code out to your workspace. If your workspaces are small then that will not be a differentiator. Some users are designing chip layouts and their workspaces are 10-15GB so for them a copy out model is not feasible.

    With a dynamic view your workspace appears to be a local filesystem so you can interact with it like you would local files.

    All the best
    • SuperDave
      SuperDave
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      Re: ClearCase vs GIT

      ‏2012-02-09T19:18:39Z  in response to SystemAdmin
      I don't know GIT, but I know ClearCase. It really depends on your end user community and the challenges they face as to what will be received in a positive light. If you can solve their problems easily and elegantly, they will like whatever tool you use. Now, to ClearCase, and I am sure you already know this stuff, but maybe for others reading, before UCM, with base ClearCase, a concept of a task (or feature) branch was commonly used. So, everything on a branch was a feature or a task. We could easily (through config spec generation) deal with parent-child tasks, re-parenting of tasks, read-only portions of code bases, etc. By generating config specs, you can have very flexible configurations, like code in common areas committed to a common branch, while code in project specific areas on a project specific branch. Also, the -time rule came in handy here to mark known good points on a branch without having to constantly lay down labels. The use of a VOB admin server process that would hand out known-good branch times to our process that dealt with concurrent commits of tasks was valuable. All of this requires an infrastructure commitment in both hardware and process people. But, with Base CC that is the game, and for the most part, is a well known method of working. UCM takes a lot of these concepts and puts them in the tool, but does not cover everything you could do by generating your own config specs and managing them. Also, dynamic views give you a lot of power, but require infrastructure to support them. In some shops, this is very critical, especially when dealing with very large files. Process around ClearCase config records can be very powerful to know what changed in broken build analysis, very quickly.
  • SystemAdmin
    SystemAdmin
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    Re: ClearCase vs GIT

    ‏2012-02-10T12:23:03Z  in response to Hamouda_screen
    Hamouda wrote:
    > I would like to get information on Pro's & Con's of ClearCase Vs GIT,
    One can compare apples to bananas, and one does it all the time.
    But the results are different if you compare them as products to import, as fruits for dessert, or as species in evolution.
    A bit of context is thus useful, nay necessary.

    Git is the third attempt from a successful Open Source project to create a vcs tool for their own need (after subversion, by the Apache folks, and with Mercurial by the FireFox crowd). This shows several things:

    1. they reckon they need something better than diff/patch and email (although Linus keeps repeating he is happy with that)

    2. they are unhappy with what they get, and they believe they can do better (in 15 minutes, said Linus)

    On (1), we must admit that Open Source has (relatively) failed so far, and I claim, largely because of the lack of a proper SCM support.
    Linux kernel, how many contributors? Compare with e.g. projecteuler (people solving maths problems for fun): it is not fun for bright people to contribute to Linux. At least not for most of them.

    Linux is successful only if you have no real ambitions.
    Windows is still kicking (despite obviously inferior in all respects), and Apple is even rising!

    Does Git address the issue? Hardly.
    Linus said that CVS was so bad that the original goal of subversion of 'building a better CVS' was non-sensical.
    Well, he did the same with making an Open Source bit keeper (source code archiving and distribution).

    The issue is not (anymore) to share a backup, but to allow developers to communicate efficiently.

    On question (2), the projects strongly state that SCM products as marketed are not useful, at least not enough to compensate for their being proprietary!
    I agree: ALM and governance are marketing bullshit(TM).

    What is interesting in ClearCase, and unknown to Linus Torvalds, as well as to IBM/Rational (who after the UCM catastrophe are developing RTC)?

    Derived Object Management, through auditing.
    Putting SCM back on its feet, by focusing on the software being run instead of on its source code.

    If it is not for this, then Git is superior to ClearCase.

    But this is the revolution which the Open Source, and the rest of the world, has been missing for the past 10 years.
    This is the killer app you want in your phone!

    Marc
    • metux
      metux
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      Re: ClearCase vs GIT

      ‏2013-08-13T01:14:12Z  in response to SystemAdmin

       SystemAdmin wrote:

      > 1. they reckon they need something better than diff/patch and email (although Linus keeps repeating he is happy with that)

      Actually,they also needed something better than svn, cvs, btk, etc, etc. 
      Something that plays well for widely distributed teams with many branches, offline capabilities, cryptographic integrity, etc.

      Can CC work offline ? (for me, it's a primary requirement)
      > On (1), we must admit that Open Source has (relatively) failed so far, and I claim, largely because of the lack of a proper SCM support.
      Which kind of "proper SCM support" do you miss ? Some examples ?

      By the way:  Git is not an SCM, it's an VCS, or directory content tracker tool, which can be used to build your own SCM upon.
      And SCM - as the name already tells - is a term for management approaches, not software tools. Git just has the fine feature that it can support so many SCM approaches instead of trying to enforce a limited set of ones some developers or product managers had in mind.

      > Linux kernel, how many contributors?

      Thousands, all over the world, working on dozens of variants and subprojects in different timezones.

      > Compare with e.g. projecteuler (people solving maths problems for fun): it is not fun for bright people to contribute to Linux.

      It is not ? What about the most famours one, who wrote a book about this, called "just for fun" ?

      > Linux is successful only if you have no real ambitions.

      Actually, I have real ambitions (also hard commercial ones, including providing high-security infrastructures for world wide banks, govermental institutions, etc) - and I'm pretty sure that Linux is quite successfull here - otherwise our customers wouldn't throw Windows out of the window (uh, accidential word game ;-o) and buy our OSS-based solutions instead.

      > Windows is still kicking (despite obviously inferior in all respects), and Apple is even rising!

      Well, my primary expertise are server applications (such as groupware / collaboration, document management, ERP, etc). 
      In that area (expect certain specific environments) I dont see where M$/Windows does better than OSS.

      And now, where everybody what IT folks already knew over 10 years ago, the whole PRISM complex (including vendor backdoors etc), the market chances for OSS are better than ever, especially where security really matters.

      > Does Git address the issue? Hardly.

      Right, the git on Windows community is pretty small, so Windows support lacks a bit behind.
      But as Windows folks usually prefer IDEs, and some IDEs (eg. Eclipse) have their own git implementation, that shouldn't be such a big problem anymore.
      > Linus said that CVS was so bad that the original goal of subversion of 'building a better CVS' was non-sensical.
      And he's really right with that. I admit, I once was big fan of SVN (CVS was really ugly to handle), before I knew git - with git I really understood to understand the concepts and value of branches, rebase, etc (SVN doesnt have such things - it just tries to emulate something branch-alike with some additional metadata, on client side - same for TFS/VSS).

      > Well, he did the same with making an Open Source bit keeper (source code archiving and distribution).

      Well, git is inspired by btk, but it's everything but a remake.

      > The issue is not (anymore) to share a backup, but to allow developers to communicate efficiently.

      No, not just a backup - it's an transaction-safe, cryptographically secured VCS, which allows building your own SCMs ontop of that, according to your needs, quite easily.

      > What is interesting in ClearCase, and unknown to Linus Torvalds, as well as to IBM/Rational (who after the UCM catastrophe are developing RTC)?

      > Derived Object Management, through auditing.

      > Putting SCM back on its feet, by focusing on the software being run instead of on its source code.

      Wait a minute, are we still talking about SCM have we magically jumped to build management ?
      Such things are absolutely not in the scope of git - there're lots of different tools for different scenarios for that, ccache can be a good starting point.

      > But this is the revolution which the Open Source, and the rest of the world, has been missing for the past 10 years.

      > This is the killer app you want in your phone!
      SCM and Build automation in a phone ? What for ?
       

      --metux

       

      • GKellner
        GKellner
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        Re: ClearCase vs GIT

        ‏2013-09-30T14:20:17Z  in response to metux

        "Actually,they also needed something better than svn, cvs, btk, etc, etc. 
        Something that plays well for widely distributed teams with many branches, offline capabilities, cryptographic integrity, etc.

        Can CC work offline ? (for me, it's a primary requirement)"

        I don't like discussion on VCS/SCM tools based on features or "primary" requirements.

        Reading the listing of VCS tools (cvs, svn, btk ...) leads to one question:
        What tool do you want to use, if your product is developed since 10 or 15 years, currently under development, and you'll  have to provide support for the product for the next xy years.
        CVS is dead, SVN isn't well, GIT is well, but the time before 2010, what kind of VCS was used and so on.
        Regarding long term projects: Which requirement is stronger: to work offline or to avoid migrations from VCS to VCS to VCS, including the development process and the way to work?

        GIT uses distributed repositories.
        For OSS projects no problem, cause there isn't any need for IT security, the source code is available in the web.
        Developing Closed Source, with strong requirements regarding IT security, can be a No-Go for GIT (or other VCS using distributed repositories).

        The list of features per tool is long and there are pros and cons per feature based on the way you work, the shop where you are, the product you are developing are individual.
        So you have to pick up the VCS/SCM which is the best for your situation.

        greetings georg.