Several system procedure tables in the master database, such as spt_values, spt_committab, spt_monitor, and spt_limit_types, are used by system procedures to convert internal system values (for example, status bits) into human-readable format.
spt_values is never updated. To see how it is used, execute sp_helptext to look at the text for one of the system procedures that references it.
In addition, some system procedures create and then drop temporary tables.
