I just saw a news group post by Paul Randal in which he explained how trace flags were grouped into certain categories and thought others may find this interesting as well. Please note that Paul stated that these are from memory so they may not be 100% accurate or complete.
Trace flags are grouped by area of SQL Server - the first two digits always denote the area. For example:
- 25xx, 52xx are DBCC related
- 8xx are buffer pool
- 36xx are SQL Server general 'run-time'
- 6xx are Storage Engine access methods
- 12xx are lock manager
- 14xx are database mirroring
- 30xx, 31xx, 32xx are backup/restore
- 55xx are FILESTREAM
- 73xx, 74xx are query execution
- 75xx are cursors
- 82xx are replication