INFO: Database Architecture Changes in 4.0, 4.0a, and 5.0 (176553)

SUMMARY

Visual SourceSafe database architecture changed dramatically between versions 3.x and 4.0. However, no architectural changes were made to the database log files between 4.x and 5.x.

This means that a Visual SourceSafe 5.0 client (build 2218, 2219, or 2220) can be used on a 5.0 or 4.0 version database. Visual SourceSafe 4.0a (build 1309) can be used on a 5.0 or 4.0 version database as well. The only restriction is that 4.0 clients (build 0811 or 0831) can only be used on 4.0 databases. The term "client" refers to the executables for the Visual SourceSafe Explorer and command line interfaces.

MORE INFORMATION

The only change to files within the 5.0 database is the addition of a 16- byte (128 bit) unique identifier (GUID) to the um.dat file. However, this Guid is not added when the 5.0 version of DDCONV.exe is run on the 4.x database. It is only added if the SSARC or SSRESTOR (archive & restore utilities) are run on the database. This is to ensure that the database can be uniquely identified for archive & restore operations. This guarantees that Ssrestor.exe knows whether the archive it is restoring is being applied to the same or a different database than it was archived from.

Restating the SUMMARY section: The 4.0 client (builds 0811 and 0831) can't read the um.dat file that contains a Guid. So they will not work with a 5.0 database. The 4.0a client (build 1309) and the 5.0 client (build 2218, 2219 and 2220) can read the um.dat file if it has a Guid or not, so these clients will work with all databases.