| Word or
Term |
Description
or Explanation |
| C |
a high level compiled language |
| C++ |
this is an object-oriented version of the C
language |
| C# |
pronounced "see sharp" - Microsoft's improved
version of the C/C++ family of programming languages, bearing more than a
passing resemblance to their illegal version of Java, and a key part of their
.NET (pronounced "dot net") strategy |
| Cache |
an area of RAM set aside for the fast storage
and retrieval of a certain type of data, e.g. font cache - all Acorn computers
since the A5000 have had a cache incorporated into the processor, giving a
massive improvement in performance - the ARM 2 and ARM 250 don't have a
cache |
| CAD |
Computer Aided Design - a computer-based
application that allows users to draw, design and model engineering
objects |
| Caps |
short for 'capitals' |
| Capslock key |
this is a key on the lefthand side of the
keyboard - when it is pressed and the Capslock light comes on, all text typed
into the keyboard appears in upper case |
| Caret |
a red vertical bar in a screen display that
marks the point at which text will appear if it is typed in from the
keyboard |
| Careware |
software for which the author requests a
nominal contribution to some suggested charity in lieu of a fee |
| Carrier |
the tone generated by a modem, on which data
is carried |
| CC |
Carbon Copy - an email header listing
recipients to whom a copy of the message should be sent - all recipients will
see this list |
| CCITT |
international body that ratifies
recommendations for telecoms standards |
| CD |
Compact Disc - a high density digital storage
medium originally intended for hi-fi sound reproduction but now applied to
storage of text and image data for various computer applications |
| CD-ROM |
Compact Disc Read Only Memory - a CD used for
the storage of computer data - it is called a ROM to emphasise that the data on
the disc, once written in the manufacturing stage, cannot be modified |
| CDFS |
filing system used for accessing CD-ROMs |
| Centronics |
the company that invented the parallel port
of the same name |
| CERT |
Computer Emergency Response Team - a group
dedicated to raising awareness of computer security issues and responding to
security incidents |
| CFS |
Compression Filing System - this is a way of
accessing a data storage system through a compression/decompression system such
that it is transparent to the user, i.e. the user need hardly know that the
data is being compressed and decompressed but just sees it as being read from
and written to the storage device |
| Chatbot |
an interactive program for conversing with
humans in natural language |
| CIX |
Commercial Internet eXchange - an agreement
among Internet service providers on the commercial use of the Internet - not to
be confused with Compulink Information Exchange which is a major UK BBS |
| ClariNet |
a hierarchy of newsgroups on Usenet that
carries commercial information from official sources - access to ClariNet is
chargeable |
| Clear (files) |
a standard format for storing and
transferring 24-bit pictures |
| CLI |
see
Command line interpreter |
| Click |
press the (left hand) button of the
mouse |
| Client |
a program on a computer attached to the
Internet which is used to access certain services, e.g. a Web client is a
program by which you can access the Worldwide Web - the term client refers to
the idea that the program provides an easy-to-use access to another more basic
program |
| a computer receiving information from a
server is also referred to as a client |
| Clock speed |
a measure of the rate at which the main
processor is being run, measured in MHz |
| Close icon |
the icon at the top left of each window, next
to the back icon which allows you to close the window |
| CMOS |
complementary metal oxide silicon (but you
don't need to know that!) - a technology used to make computer chips - see also
CMOS RAM (next) |
| CMOS RAM |
low-power RAM chips that are used in most
Acorn computers to store certain characteristics of the way the user wants to
computer to start up- the information in this CMOS RAM is held with a small
battery so that it is not lost when the main power is switched off |
| CMYK |
Cyan, Magenta, Yellow, Key - a method of
specifying colour by using the amounts of the three primary (subtractive)
colours plus the amount of black (Key) |
| Colour depth |
every pixel on a computer screen display has
its colour defined by a certain number of bits of data - the colour depth
refers to the range of different colours available for each pixel in a
particular screen mode - if a single bit were used, it would only allow it to
be one of two colours - usually black or white - if it were defined by two
bits, it could have 4 (22) different colours, four bits would
provide (24) 16 different colours, 8-bit provides 256
(28) colours, 16-bit gives over 32 thousand colours and 24-bit
allows each pixel to have any of about 16.7 million different colours - about
as much as the human eye can distinguish - the 32-bit colour of the RiscPC
"only" gives 16 million colours but the extra 8 bits can be used by the
computer to produce various different special effects |
| Command line |
a way of accessing a service by typing in
textual commands |
| all Acorn computers now come with a WIMP
interface - however, it is possible to give the computer operating system
commands by typing them in from the keyboard - if you press <f12>, a star
prompt appears - this is the command line - you can enter commands such as
CAT<return> to get a catalogue of the current storage device |
Command
line
interpreter |
pressing <f12> allows you to type
command lines into your RISC OS computer - these are then interpreted by the
CLI |
| Command Shell |
a process which receives and processes a text
command string - typically invoked in either of two modes: direct keyboard
input or a call from another process - output may be to screen, file or yet
another process |
| Compact Flash (CF) Card |
a form of Flash Memory on a removable card -
often used in digital still cameras such as Mustek |
| Compiler |
in a computer language, instructions that the
programmer enters as (vaguely) understandable words have to be translated into
series of the very simplest steps that the cpu executes - these simple
instructions are called machine code - the job of a compiler is to take the
whole of a program and convert it into a single machine code program which can
be executed then or at a later stage - this contrasts with an interpreted
language in which each individual line of the program is converted into machine
code as the program is running - in a compiled language, you have to convert
the whole program before you can run any of it whereas in an interpreted
language you can run the program at any time, stop it, change the program and
run it again - on the other hand, interpreted programs tend to run more slowly
because even if one line of the program is run many times, it has to be
interpreted into machine code every time it is run |
Compression/
decompression |
there are various mathematical techniques
which can be used to store (and transmit) computer data using a smaller amount
of memory than the uncompressed data represents - some of these techniques are
completely reversible so that the decompressed data is identical to the
original data - however, in the case of images, it may be acceptable to allow a
degree of degradation of the data in order to increase the amount by which the
data is compressed |
| Compuserve |
a large international BBS with limited
Internet access |
| Concept keyboard |
an input device consisting of a flat panel,
usually A4 or A3 sized, that has a matrix of pressure switches below the
surface - different sheets, called overlays, can be placed on top of the panel
to show the user which areas to press to get certain responses from the
application software that is currently running - they are particularly useful
in primary school or special needs situations |
| Configuration |
a collection of settings and options which
describe how the computer will operate when it is first switched on |
| Control codes |
special non-printing ASCII codes which cause
a device to perform some electronic or mechanical action, e.g. ASCII 10 is
linefeed, 13 is a carriage return and 12 ejects the paper or clears the
screen |
| Cookie |
a message given to a Web browser by a Web
server - the browser stores the message in a text file called cookie.txt. The
message is then sent back to the server each time the browser requests a page
from the server |
| the main purpose of cookies is to identify
users and possibly prepare customized Web pages for them - when you enter a Web
site using cookies, you may be asked to fill out a form providing such
information as your name and interests - this information is packaged into a
cookie and sent to your Web browser which stores it for later use - the next
time you go to the same Web site, your browser will send the cookie to the Web
server - the server can use this information to present you with custom Web
pages - so, for example, instead of seeing just a generic welcome page you
might see a welcome page with your name on it |
| the name cookie derives from UNIX objects
called magic cookies - these are tokens that are attached to a user or program
and change depending on the areas entered by the user or program - cookies are
also sometimes called persistent cookies because they typically stay in the
browser for long periods of time |
| Coprocessor (1) |
see
Second processor |
| Coprocessor (2) |
also used of any hardware such as an FPA that
is used to extend the instruction set of the CPU |
| CPS (1) |
cycles per second |
| CPS (2) |
characters per second - a way of measuring
the speed of dot matrix or inkjet printers |
| CPU |
Central Processing Unit - this is the
electronic circuitry at the heart of a computer that executes (very rapidly!) a
series of simple steps of reading, manipulating and writing information to and
from the computer's RAM memory and input/output devices |
| CRC |
Cyclic Redundancy Check - this is a way of
checking for errors in stored and transmitted data |
| Crop marks |
in publishing, it is important to define
where a printed image appears in relation to the edges of the paper - to do so,
the images can be printed on a larger sheet of paper and markers placed on the
sheet to show where the corners of the paper will be |
| Cross-posting |
sending the same article to more than one
Usenet newsgroup at a time |
| CSLIP |
Compressed SLIP |
| CSS |
Cascading Style Sheets - an extension of HTML
which gives both website designers and users more control over how pages are
displayed, by using style sheets |
| CSV |
Comma Separated Variables - a standard way in
which data is stored in a file where the items of data are separated by
commas |
| Cyberspace |
the virtual world that exists within computer
networks |
| Cyrix |
a microprocessor manufacturer |