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Unformatted text preview: variable-word-length memory because a character can be placed in every
storage cell of this machine. However, word-addressable computers possess faster
calculating capability because they can add two data words in a single operation. If the
fixed-length word is eight characters, two eight digit numbers can be added in single
operation. On the other hand, with a character-addressable machine only one digit in each
number is added during a single operation and eight steps would thus be needed to add
two eight digit numbers.
A computer may be designed to employ either a fixed-word-length or a variable-wordlength memory organization. The set of instructions available with these computers allow
them to be operated as either variable-or fixed-word-length memory computers.
However, with the memory becoming cheaper and larger day-by-day, most modern
computers employ fixed-word-length memory organization. Main Memory Capacity
The main memory capacity of large computer systems is normally more than small
systems. This capacity is defined in terms of the number of bytes a computer system can
Memory capacity of a computer system is normally stated in terms of kilobytes (KB)
which is equal to 1024 (2 ) bytes of storage, or in terms of megabytes (MB) which is
equal to 1,048,576 (220) bytes of storage, or in terms of gigabytes (GB) which is equal to
1,073,741,824 (230) bytes of storage. Notice that 1 KB is about 10 3 bytes, 1 MB is about
106 bytes, and 1 GB is about 10 9 bytes, thus the origin of the prefixes kilo (thousand),
mega (million) and giga (billion). Few years ago, memory capacities were stated only in
terms of KB. With the rapidly increasing capacity of memory, today memory capacity of
small computer systems is stated in terms of MB and that of large computer systems is
stated in terms of GB. The memory capacity continues to increase rapidly and it is only a
matter of time before we start stating memory capacity in terms of terabytes (TB), which
is about one trillion (1012) bytes. Today, GB and TB are frequently used to refer...
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- Spring '14