WORD CONTENT

 4 Type Code

 -1 = Data Item no longer needed

 1 = Program

 2 = Data

 3 = SII

 4 = INDEX COMMON

 5 Absolute Address of First Word

 6 Number of Logical Records Spanned by Data Item


Each data item is assigned a unique name when it is stored. It is with

this name that data items are referenced. When a data item is stored,

its name must be "remembered" by the routine which initiated the store

or the data item will not be recoverable. In addition to a name, a data

item has associated with it a type code as illustrated above. This is

not actually needed for this type of accessing of the directory but

does provide a double checking to assure that the data item accessed is

of the type expected. The absolute address is the absolute random

access address as discussed above. The number of records spanned is the

number of different random access records which would contain elements

of the data item in question.

 Suppose that a data item previously stored is to be restored to

its COMMON area. First the memory system must determine its absolute

address, which is part of the directory entry. This is done by a simple

search of the directory for the correct name and type code. Next it

must be determined whether or not the data item is in MEMORY. First,

however, care must be taken to insure that data currently stored in