Figure 13.2
Expert system for separation sciences.puters are designed to handle 8, 12, 16, 24, etc., groups of bits at a time, the number in the group being
termed the word length; an 8-bit word is called a byte. Large or mainframe computers may use word
lengths of 16, 32, or 64 bits whereas mini- and microcomputers (see below) use 32- or 64-bit words.
There are two types of memory used in computers. The main memory is based on integrated circuit
chips and all parts can be accessed with great rapidity and with equal ease. In mainframe computers this
is known as the main store whilst in smaller computers, including microcomputers, it is called the
random access memory (RAM). Some parts of RAM may be reserved for the storage of programs or
data which are to be protected from change or accidental erasure. Such a reserved area of memory is
called read only memory (ROM). ROM chips, sometimes called firmware, are often used in integrators
and microcomputers dedicated to particular tasks. The