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Difference between hardlink and softlink in Rational ClearCase

Question & Answer


Question

What are the differences between IBM Rational ClearCase hardlink and softlink?

Cause

ClearCase supports both hardlink and softlink. Both are working the same way as the original UNIX implementation.

Answer

  • A hardlink is an additional entry in a directory for an existing file.
    Only one copy of the file exists on the harddisk. If you modify any copy, you modify all other copies. ClearCase does this at directory structure through the same inode and increases the reference count by 1.

  • A softlink is like a pointer to an existing file.
    The directory contains a path, relative or absolute, to the destination file.


When you use ClearCase, the way both links work depends of the type of view and the operating system.
.
  • Under UNIX, hardlink and softlink work in the original way.

  • Under Microsoft Windows

    • In a dynamic view (MVFS), hardlink and softlink work the same way as under UNIX.

    • In a snapshot view, ClearCase uses the Windows file system. Windows does not support hardlink or symlink. ClearCase creates a copy to simulate them. This means that checking out one copy will not update the other one in real-time. This happens during the view update.


Note:
In a ClearCase VOB, hardlinked elements have the same oid, pointer to the same file, but symlink will not.

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Document Information

Modified date:
19 February 2019

UID

swg21407967