Control Data 3100 Reference Manual page 201

GLOSSARY
A REGISTER - Principal arithmetic register; operates as a 24-bit additive accumulator
(modulus 224-1).
ABSOLUTE ADDRESS- Synonymous with Address.
ACCESS TIME - The time needed to perform a storage reference, either read or write.
In effect, the access time of a computer is one storage reference cycle.
ACCUMULATOR-A register with provisions for the addition of another quantity to
it-s content.
ADDER-A device capable of forming the sum of two or more quantities.
ADDRESS - A 15-bit operand which identifies a particular storage location; a 17 -bit
operand which identifies a particular character location in storage.
ADDRESS MODIFICATION - Normally the derivation of a storage address from the
sum of the execution address and the contents of the specified index register.
AND FUNCTION -A logical function in Boolean algebra that is satisfied (has the value
"I") only when all of its terms are "1's". For any other combination of values it is
not satisfied and its value is "0".
ARGUMENT - An operand or parameter used by a program or an instruction.
ASSEMBLER-A program which translates statements to machine language. Normally,
one source language statement results in the generation of one line of object code.
BASE - A quantity which defines some system of representing numbers by positional
notation; radix.
BINARY -CODED DECIMAL (BCD)- A form of decimal notation where decimal digits
are represented by a binary code.
BIT - Binary digit, either "1" or "0".
BLOCK-A sequential group of storage words or characters in storage.
BOOTSTRAP - Any short program which facilitates loading of the appropriate system
executive.
BRANCH - A conditional jump. Refer to Jump.
BREAKPOINT- A point in a routine at which the computer may be stopped by manual
switches for a visual check of progress.
BI, B2, B3 REGISTERS- Index registers used primarily for address modification
andlor counting.
BUFFER - Any area that is used to hold data temporarily for input or output, normally
storage.
BYTE - A portion of a computer word.
CAPACITY -The upper and lower limits of the numbers which may be processed in
a register, or the quantity of information which may be stored in a storage unit. If
the capacity of a register is exceeded, an overflow is generated.
CHANNEL - An Input/Output
(/0)
transmission path that connects the computer
to an external equipment.
CHARACTER-A group of 6 bits which represents a digit, letter or symbol from the
typewriter.
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