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Glossary to Some Computer Terms.

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Glossary of Some Computer Terms
A/D converter (Analog-to-Digital converter)-a device for
converting an analog value (usually an electrical voltage)
into a numerical representation.
Floating-point instructions-instructions for processing
data coded in floating-point format, that is, data expressed
as an exponent and a mantissa.
Batch operation-programs are processed sequentially,
possibly in parallel running “batch streams” (“multiprogramming batch). No interactive work.
Hardware-the
Bit-a digit position in the binary number system ;derived
from “binary digit”.
Byte-a group of binary positions (bits) treated as a unit.
Most byte-oriented computers work with 8-bit bytes. One
character (letter or number) is stored in a byte. Wordoriented computers (for example, the PDP 10) sometimes
offer instructions which permit working with variablelength bytes.
material part of a computer system
High-level programming language-allows the user to
express algorithms in a computer independent form; a
problem oriented as opposed to computer oriented form
of expression. FORTRAN and BASIC are two such languages.
“Integrated instrument-an instrument with a “built-in”
computer ;sometimes also called an “instrument computer”.
Interactive time-sharing operation-see
time-sharing operation.
conversational
instructions which manipu-
Interface-an electronic adapting unit between instrument
and computer.
Channel status-the
current state of the parameters
characteristic for data acquisition, for example, “active”,
“inactive”, data rate, run-time.
Interrupt system-an arrangement whereby brief interruptions of the running program are permitted if a data
word (or byte) is to be transferred to or from a peripheral
unit.
Closed-loop operation -experimental parameters are controlled by the computer during an experiment by analyzing
measured values.
Job-a sequence of tasks for the computer which are
initiated by a user at a terminal (or by submission of a deck
of cards).
Core image-the momentary state ofa program in memory
during program execution.
K-abbreviation for 21° = 1024. For example, a core
memory capacity of 32 K words corresponds to 32 x 1024
= 32768 words.
Byte instructions-computer
late bytes.
Contact scanner-a device which enables the computer to
determine the state of on-line instruments and register
related signals (for example, start and stop signals).
Conversational time-sharing operation-a time-sharing
system (see definition) which permits a programmed dialog
between the user and the computer.
Data buffer- temporary storage for accumulating data.
The use of data buffers allows a more rational handling of
data.
Data rate-transfer rate of data, expressed in words, bits,
bytes, data points, etc., per unit time.
Data reduction-decreasing the extent of information of
measured data to an amount or form essential to a problem.
D/A converter (Digital-to-Analog converter)-see
converter.
A/D
Line-driver-a unit which allows the program-controlled
opening and closing of circuits, and therefore the control
of on-line instruments.
Monitor-see
operating system.
Multi-mini system-a computer system which is made up
of several small computers. One of them can function as the
central processor and all of the others are connected to it.
The small computers can also be organized in a network
fashion.
Multiplexer-a device used if a data path is to be switched
among several instruments; in on-line systems a multiplexer is used with an A/D converter common to several
instruments.
Off-line operation-the computer processes jobs which, in
contrast to on-line operation, have no real-time requirements.
Dedicated system-a system in which a computer is used
strictly for the data acquisition and processing for one
single instrument (or a group of instruments of the same
type, for example several chromatographs).
On-line operation- the computer is directly coupled to
analytical instruments.
Disk-a magnetic data storage medium. Several magnetic
disks can be grouped in a stack on a rotating axis. One
distinguishes between a fixed-head disk (one readfwrite
head per concentric path) and a movable-head disk (one
head per surface).
Operating system, monitor-an executive or controlling
program which regulates the progress of computer operation, that is, the distribution of computing time, the allocation of core storage, and the use of peripheral units for the
different jobs.
Enable-a condition which exists when several switching
signals yield a “true” value in an AND function.
Periphery-the “exterior” devices of the computer such as
card readers, magnetic tapes, and line printers.
Failsafe system-a computer system which is safeguarded
against failures of hardware and software components.
Priority levels-a graduated hardware interrupt system
allows not only program interruption, but permits a data
Angew. Chem. internat. Edit. / Vol. I 1 (1972) / No. 5
403
transfer between the computer and its periphery according
to speed requirements and reai-time demands ;data transfers in progress on lower priority levels are interrupted if an
interrupt signai is received for a level of higher priority.
Besides such hardware priority levels, there are also software priority levels in the form of different queues, in which
the programs to be run are placed, depending on their
instantaneous status, requirements, size, etc.
Process-control computer-a computer which is used for
supervision and control of experiments, manufacturing
processes, and so on.
Random access-a programmed reading or writing of data
on a storage medium independent of where the data is
actually stored. Possible with magnetic disks, drums, and
core storage, but not with magnetic tapes, paper tapes, etc.,
that have to be read or written serially.
Real-time data acquisition-the computer takes data from
an analytical instrument in real-time, that is (with a delay
of a few microseconds) during the measurement.
Satellite computer-a subordinate (small) computer for
handling tasks given to it by a central computer.
of the operation) and “application software” (problemoriented programs).
Swapping operation-movement of programs (in the form
of their core images) between disk or drum units and core
storage, should total core capacity be insufficient to hold
all currently active programs.
Teletype-a
company product designation which has
become a common term to mean any input/output typewriter-like device used as a computer terminal.
Terminal-data
station (for example, teletype, display
device) which allows the user to communicate with the
computer.
Text editor-a program for the creation and correction of
programs and data sets by type-in from a terminal.
TI correction-correction of intensity distortions caused
by pressure changes during the running of a mass spectrum.
Time-sharing system-a system which allows several users
to work with the computer simultaneously.
TTY-an
abbreviation for teletype (see definition).
Software-computer programs ;one distinguishes between
“system software” (necessary for operation or the support
[A 875 IE]
German version: Angew. Chem. 84,429 (1972)
An Alternative Approach to the Nomenclature of Cyclic Conjugated
Polyolefins, together with some Observations on the Use of the
Term “Aromatic”
By Douglas Lloyd and D. R. Marshall[*]
So much ambiguity and disagreement has arisen concerning the usage of the word ‘aromatic’
that it might be better to discontinue the use of this term.
1. Introduction
The term ‘aromatic’ is remarkable in organic chemistry
for the variety of meanings and interpretations which have
been ascribed to it in more than a century of use. Perhaps
even more remarkable is the fact that although this word is
one of the commonest used by chemists, it has no firmly
defined meaning and different individuals may mean very
different things by the term. This indeterminacy stems to a
large extent from its checkered history with ever-changing
meaning.
[*I Dr. D. Lloyd
Department of Chemistry, Purdie Building
University of St. Andrews
St. Andrews Fife (Scotland)
Dr. D. R. Marshall
Department of Chemistry, University College of North Wales
Bangor Caernarvonshire (Wales)
404
In recent years a number of definitions, some more satisfactory and explicit than others, have been made but on the
whole each individual tends to use the term to suit his own
preconceived ideas. Furthermore, the avidity with which
contemporary chemists use this magic term was commented
on by a speaker at a recent symposium on “Aromaticity,
Pseudoaromaticity, Antiaromaticity’”’’ who described it
as the modern chemists’ equivalent of being possessed by
devils.
2. Original Meaning and Changes in Meaning
of the Term “Aromaticity”
The term ‘aromatic’ was first applied by chemists in the
early part of the nineteenth centry to describe compounds
which had an aromatic odour and which had been isolated
Angew. Chem. internat. Edit. 1 Vol. I 1 (1972j
1 No. S
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