| Word or
Term |
Description or
Explanation |
| Obey file |
a file of commands prepared for execution by
the RISC OS command line interpreter |
| Object code |
the machine-executable code produced by a
compiler |
| Object oriented |
the approach used in conventional programming
is to have a number of procedures or routines which can work on some data -
there is no conceptual connection between the data and the operations which are
performed on it - in contrast to this, object-oriented programming works on a
concept of objects, which consist both of data fields (similar to a structure
in C) and of a list of methods which may be applied to that data - for example,
you could define an object point (with data x and y, both integers), and define
a move method on it to change these fields |
| one of the most useful concepts which may be
derived from this is inheritance - an object can be defined as a sub-type of
another object, and in doing so inherit all its methods (and data fields), but
may also add its own - as an example, you could define a circle object with
data x and y (inherited from the parent point object) but with
another data field, radius - similarly, the circle would inherit the
move method (which would not have to be rewritten), but could also have a
resize method added to it |
| the result of these changes in approach is that
it is often easier to implement large programs, since it is harder to get
confused about how a piece of data should be used, and less code needs to be
rewritten - object-oriented languages include Modula-3, C++ and Objective
C |
| OCR |
Optical Character Recognition - computers can
be trained to examine the shapes of typed or printed characters and work out
what the letters, words and sentences are - so, combined with a scanner or
camera and digitiser, the computer can 'read' text off books and paper -
because of the difficulty of being 100% accurate, it may take as long to edit
out the mistakes as to type the text in from scratch, so OCR programmers are
fighting all the time to make their programs more and more accurate without
becoming too slow for practical use - this facility will become more viable as
we get progressively faster processors |
| Offline |
when your computer is not connected to a host
system or the Net, you are offline |
| OLE |
Object Linking and Embedding - this is a means
of linking data of different types (e.g. text, drawfiles, sprites, etc.) within
one document so that each element can be easily edited - double-clicking on an
element brings up the appropriate editing application (Draw, Paint, ArtWorks,
etc) to allow you to make the necessary changes without having to export and
then re-import the data |
| OLR |
Off-Line Reader - software used for reading
email or Usenet news off-line |
| OMR |
Optical Mark Recognition - a system where when
a sheet is passed through a scanner, the computer tells where the marks are and
uses them to automatically fill out forms or similar - it means that forms can
be filled out quickly by various people and fed into the computer which
automatically sorts the data out according to the marks and programming -
however, the system can reject a large number of forms as the system can not be
very accurate - it depends on the person putting the marks on the paper |
| Online |
when your computer is connected to an online
service, bulletin-board system or public-access site |
| Operating system |
this is the set of "house-keeping" programs
within a computer which handle all the input/output, filing systems, etc. - all
modern Acorn computers come with the RISC OS operating system as standard
(stored in ROM) but it is possible to use alternative operating systems such as
DR-DOS and MS-DOS by adding the appropriate software or hardware |
Optical Mark
Recognition |
see OMR |
| Option icon |
an icon that appears in a dialogue box - each
time you click on it, you will switch a particular option on or off |
| OS |
Operating System - see above |
| OS graphic unit |
a unit for defining graphics under RISC OS so
that they are independent of the current screen mode - there are nominally 180
OS graphics units to the inch |
| OSCLI |
Operating System Command Line Interpreter - the
part of the RISC OS operating system that deals with command lines that are
either typed in at the keyboard or issued by other programs |
| Outline fonts |
these are fonts that are described
mathematically by using equations to define the curves that make up the outline
of the character's shape - using these equations, it is relatively simple to
work out how to display any font at any size, either on the screen or on a
printer where the shape has to be reproduced as a series of dots |