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Other information:
On this page we
discuss some some of the terms we've used throughout our website and
attempt to explain the rational behind our advocacy of the use of open
source.
Multi-tier system
A
multi-teir database system is a system in which the management and
storage is independent of the programs accessing and manipulating the
data. The usual way a mutli-tier system is implemented is to have
a server on which the client's data resides, to access the data client
requests via a virtual socket are made to a database engine (eg.
Postgresql or MySQL) which may, though not necessarily, reside on the
server, the engine then returns only the data found by the search
request. Using a database engine provides quick and efficient
access to data along with the advantage that data replication is made
easy so multiple copies of data can be made concurrently providing
resilience and security.
The client in the above example is
known as a thin client as it only every recieves the minimum amount of
data required to process its given task. Click here for a diagram of a
multi-tier database implementation
The alternative to this a
thick client whereby the client program holds and handles all the data
and actions required to manipulate data. A thick client is acceptable
for single PC systems but doesn't scale up very well if multiple users
wish to accesses the data conncurrently and is also very inefficient
across a wide area network such as the internet.
Open source
Often
refered to as free software. Free in this instance refers to free
speech not free beer though more often than not the software is given
free. Open source means that you as a user have open access to the
source code which was used to generate the program you are running.
The advantages of open source software are :
- It's
usually community supported so there are thousands of experts world
wide who have been involved in creating the programs and are experts in
its fuctionality
- You have the right to use and modify the software in any way you see fit.
For a full and indepth discussion of open source software click here.
Linux
An
open source multi-task, multi-user operating system. Microsoft
Windows should not be considered a multi-user operating system. Even
those multiple users may be defined on a Microsoft Windows PC only one
use can access the operating system at any given time. Linux was
devised by Linus Torvalds in 1992 and was based on the very expensive
Unix operating system. Linux is fully configuarable and works
beautifully as a server operating system as all non-essential services
can be switched off (eg any window drawing fuctionality) leaving all
the processing power and memory to be configured to run services such
as database engines or filesharing facilities.
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