Welcome Back Clearcase

I recently started a new job. They haven't given me a computer yet. So to pass the time I broke out my old Clearcase Manual. Now this book is for version 3.2 of Clearcase running on Windows NT. But many of the topics are relevant to any version of Clearcase. So I thought I would share some facts I have relearned while reading the book.

The Windows version of Clearcase is integrated with Windows Explorer. You can issue the "cleartool man" command to see the reference pages. Clearcase is both a version control system and a configuration management system. It is designed for use by teams. Clearcase has a command line interface (CLI) as well as a GUI one. The Clearcase Home Base allows access to most of the tools in Clearcase.

Clearcase objects have properties which are separate from Windows properties. A VOB (versioned object base) is a public storage area. A view is a private storage area for one user. There are two types of views: snapshot and dynamic. You need to use a view to access the VOB. Starting the view activates it so that data appears as a directory to Windows. You must mount at least one VOB and start at least one view to use Clearcase.

The config spec contains the rules that a view uses to select a version. A view can have only one checkout of a given element. Once checked out, only you and the administrator can undo your checkout. There are two types of checkouts: reserved and unreserved. Reserved checkouts are the default, and give an exclusive right to extend a branch to a new version. Unreserved checkouts allow multiple views to get a copy on the same branch, and requires a merge on checkin. The Merge Manager is a GUI tool to help resolve conflicts during the merge.

The Version Tree Browser is a tool which, among many other things, allows you to:
  • compare versions of a file
  • view meta data (such as labels)
  • view a history of events on an object

A View Profile is an optional feature that allows common Clearcase information to be shared by a development team.