Commander manages command interpreter handles, primarily used by the CommandTool. Access to the registry of commands is properly monitorized. Access to Commander objects is not monitorized (concurrency is the client's responsibility).

PriorityQueue manages priority queue objects, which support insertion of arbitrary objects, with fast removal of the "best" object (determined by user predicate). Access to PriorityQueue objects is monitorized for concurrent access.

Prop provides an immutable property-list abstraction.

Random manages simple random number generator streams. Access to Random streams is monitorized for concurrent access.

RedBlackTree manages ordered symbol tables, where the user provides the sorting predicates. It uses self-adjusting trees to keep the nodes, with expected time of log(N) for insertion or deletion operations (worst case time of N). Access to RedBlackTree tables is monitorized for concurrent access.

RefTab manages hash tables that map from from REFs to REFs based on address equality, or on client-supplied equality and hash functions. It is a reasonably fast method of maintaining associations between objects. Access to RefTab tables is monitorized for concurrent access. Tables will grow as necessary to keep the density limited; see HashTableDoc.tioga for a lengthy discussion of this implementation.

RopeFile provides a means of making files into ropes. It is used underneath large Tioga files, although it has no Tioga dependence. Access to RopeFile ropes is monitorized for concurrent access.

RopeFile registers two Commander commands, RopeFiles and RopeFileParam, for inquiring about the status of RopeFile objects and setting various global parameters.

RopeList manipulates lists of ropes much in the same way as List manipulates lists of REFs. Access to RopeFile ropes is not monitorized, concurrency is the responsibility of the client.

Scaled provides arithmetic on 32-bit quantities with 16 bits of fraction.

SymTab manages symbol table objects, each of which is a fast hash table mapping from ropes to REFs. The hash size can be given at symbol table creation time to allow for tuning to the expected contents; as with RefTab, the table will grow as necessary to keep the density limited. The symbol lookup can be either case dependent (as for Mesa identifiers) or case independent (as for file names). Access to SymTab tables is monitorized for concurrent access.

Minimum interface to access environmental parameters.

This interface allows to hide the actual operating system features used from the client program, therefore making the client program portable.

On Unix, this interface is implemented using "environment variables".