backing store

1. storage Computer memory, usually magnetic disks,

storing data and programs. Sections of this information can

then be copied into the main memory (RAM) for processing.

Backing store is cheaper but RAM is faster. Such a hierarchy

of memory devices allows a trade-off between performance and

cost.

2. text Character storage in memory or on disk, as opposed

to displayed or printed characters. This distinction is

important where the visual ordering of characters differs from

the order in which they are stored, e.g. bidirectional or

non-spacing layout.

In a Unicode encoding, text is stored in sequential order in

the backing store. Logical or backing store order corresponds

to the order in which text is typed on the keyboard (after

corrections such as insertions, deletions, and overtyping). A

text rendering process converts Unicode text in the backing

store to readable text.

["The Unicode Standard: Worldwide Character Encoding", Version

1.0, Vol. 1. Addison-Wesley, 1991].

(2001-02-25)