In serial transmission, bits are transmitted one at a time over a
single wire/channel. This reduces the cost of the cable, but gives
a slower rate of data transfer. There is also some additional
complexity, as bytes have to be disassembled into individual bits
for transmissions and then reassembled after receipt. Serial
transmissions can can be used over large distances.
Parallel Transmissions
In parallel transmission, a number of bits of data are transmitted
simultaneous over an equal number of wires/channels. This allows
the bits in a whole byte of information to be transmitted together. It
has a short range, with an absolute maximum of around 5 metres.
Parallel transmission used to be popular for connecting printers to
computers but it is rarely used these days in computing because of
the cost and limited range.
Bi-directional Transmission
It has several meanings within data
communication, but its essentially about
transmitting in both directions. Most recently
the term has been applied to fibre optics.
Using the current technology, light passes in
one direction only, so you have to add extra
fibres to the bundle to carry a signal in the
opposite direction.
Client Side Processing
Client side processing is the use of a scripting
language to create code on web pages which provide
interactivity. An example of this is a rollover action; this
is where some code is triggered when your mouse is
moved over a particular part of the web page.
:) Speed - the interaction may be faster once
the code has been downloaded with the
page, Security - its more secure as the entire
action takes place in the downloaded page
and nothing comes from the browser , which
could cause corruption or security problems.
:( Its browser specific - not all scripts work the same
way on all browsers, so you may have to create different
versions depending on the browsers used. Computer
Speed - it can be affected by the speed of your own
computer. As all the activity is taking place on a
downloaded web page, the speed of processing will
depend on your computer system. If the processing is
complex or resource hungry, it may run slowly or cause
other programs to run slowly on your system.
Server-Side Processing
Involves the use of scripts which reside and are run on
another computer on the internet. Information is
submitted to a server which processes it to provide
results in the form of a web page. A good example of
server-side processing is the submission of a search
through a search engine. The search engine matches
the word or phrase against an index of website content
on the web server using scripts.
:) Efficiency - complex code may run more
efficiently, as it does not have to be downloaded
on to the user's computer, Browser independent
do therefore can be run on any web browser on
the web server, the speed of your own computer
is only significant for the downloading of the web
pages. All of the other processing takes place
on a higher resourced and speedy server.
:( Security - the exchange of data
over the network may present
security risks, Overloading - a server
needs to be able to cope with large
volumes of users.
USB
Universal serial bus - a serial transmission method which was
introduced to make many connections to Universal serial bus, a
serial transmission method which was introduced to make many
connections to a computer look the same. Nowadays, USB id
used in mobiles, memory sticks and MP3 players. Also, provide
power to some devices.