[Note: this chapter will be completely rewritten in the next edition of this manual, to reflect the existence of the garbage collector. The present chapter is very incomplete.] Storage in the Lisp machine is divided into areas . Each area contains related objects, of any type. Areas are intended to give the user control over the paging behavior of his program, among other things. By putting related data together, locality can be greatly increased. Whenever a new object is created, for instance with cons , the area to be used can optionally be specified. There is a default Working Storage area which collects those objects which the user has not chosen to control explicitly. Areas also give the user a handle to control the garbage collector. Some areas can be declared to be "static", which means that they change slowly and the garbage collector should not attempt to reclaim any space in them. This can eliminate a lot of useless copying. All pointers out of a static area can be collected into an "exit vector", eliminating any need for the garbage collector to look at that area. As an important example, an English-language dictionary can be kept inside the Lisp without adversely affecting the speed of garbage collection. A "static" area can be explicitly garbage-collected at infrequent intervals when it is believed that that might be worthwhile. Each area can potentially have a different storage discipline, a different paging algorithm, and even a different data representation. The microcode will dispatch on an attribute of the area at the appropriate times. The structure of the machine makes the performance cost of these features negligible; information about areas is stored in extra bits in the memory mapping hardware where it can be quickly dispatched on by the microcode. These dispatches usually have to be done anyway to make the garbage collector work, and to implement invisible pointers. Since the garbage collector is not yet implemented, the features mentioned in the previous two paragraphs are not either. Also, with the implementation of the garbage collector will come a new, more sophisticated area scheme. The two most visible effects of the new scheme will be that garbage will be collected, and that areas will be able to shrink and grow. When this happens, it will be documented; stay tuned. Most of this chapter will become inoperative at this time, so don't depend on it. Each area has a name and a number. The name is a symbol whose value is the number. The number is an index into various internal tables. Normally the name is treated as a special variable, so the number is what is given as an argument to a function that takes an area as an argument. Thus, areas are not Lisp objects. The following variables hold the areas most often used:

Example:
(make-area ':name 'foo-area
	   ':gc ':dynamic
	   ':representation ':list)