Suppose following cases - You have working code. You edit that code and save it. New code doesn't work so you want to go back to previous code. - You deleted important files by mistake. - A hard disk drive has broken down. ====================================================================== Suppose following cases when you create project with other people - Who should have "official (or master)" code? - How can you know where each member edit from the codes? - How can you get codes which other members edit? Via email? or By using USB? - What if I edit same place from code which other people are also editing? You can overwrite elaborate codes which other people have done. - Some important files have got problems. How to sustain backup the important files? ====================================================================== Version control system (VCS) is a software which tracts and manages manipulations on the codes, files, structures - Similar functionality with VCS: undo functionality in word processor ====================================================================== VSC like Git does these: - Git provides shared master repository to all members - Git manages multiple versions including current version and backup version - Git lets you know where and how members edit on a source code - If multiple members edit the same place, Git prevents the conflict from happening - Git allows you to apply Git functionality to other forms of resources like pictures, other types of documens ====================================================================== Repository in Git system is the place where files and history of manipulations are stored Repository stores version1, version2, version3 You can bring version3 code to use Or you can bring version2 or 1 code to use ====================================================================== Centralized VCS is general form ====================================================================== Some other complicated form of VCS is distributed VCS. ======================================================================