Scache is alternate approach to PHP sessions
Scache is high performance session manager for distributed web applications' session data. SCache provides both persistent and on-demand expiring key-value storage with structured filesystem-like keyspace for referencing the data.
Scache gives more flexible control to your session than plain $_SESSION can provide. It is designed to give tools for inter client communication and sharing data between web applications clients.
Scache consists of freely available GPLv3 distributed PHP-extension and backend server. Having very small system footprint, it is suitable from small embedded setups to large clustered php applications requiring fast simultaneous lockless access to common transient data.