ColdStore is a gigabyte-scale persistent object store which mmap()s objects into a file (for persistence), can allocate objects in a minimal working-set of pages (for speed), permits library versions to change without a rebuild of the store, permits application checkpoint/restart. ColdStore might be used to replace a database, cache highly structured objects, act as an OODB, make STL persistent, act as a Document Store for XML/SGML/HTML, create a MUD. Future projects include a virtual machine toolkit, ports of several languages, VM and byte-interpretive language workbench.