SIDs

An SCCS delta ID, or SID, is the number used to represent a specific delta. This is a two-part number, with the parts separated by a dot ( . ). The SID of the initial delta is 1.1 by default. The first part of the SID is referred to as the release number, and the second, the level number. When you check in a delta, the level number is incremented automatically. The release number can be incremented as needed. SCCS also recognizes two additional fields for branch deltas (described under "Branches ").

Strictly speaking, an SID refers directly to a delta. However, it is often used to indicate the version constructed from a delta and its predecessors.