Introduction to information systems T. Cornford, M. Shaikh is1 060 2013

client computer
, which 
provides the interface to the user, and that of a 
server computer
, 
which provides services across the network. Thus, my desktop PC is a 
client computer, when it connects to a mail server computer across the 
network at the university so I can send or receive email. Figures 5.2 and 
5.3 in Laudon and Laudon (2013) show schematic descriptions of the 
client–server approach and more generally describe the period from about 
the mid-1980s as the ‘client–server era’, as networked units of computing 
resources were used to build the basic computing capacity, rather than 
relying on centralised mainframes. Of course, the internet itself is based 
on the principles of the client–server approach. This era is then overtaken 
by what Laudon and Laudon (2013) refer to as the ‘enterprise Internet 
era’ from the mid-1990s. For a more detailed description of client-server 
computing and the general distributed approach, see Curtis and Cobham 
(2008) Chapter 4. 
Laudon and Laudon (2013) end up with the final era named as the ‘Cloud 
and Mobile era’, and that quite well categorises the contemporary leading 
edge in technology and infrastructure terms. Although, as they make 
clear, earlier generations of technology are in use and remain important, 
still. The cloud model is sometimes termed as a utility model, with a 
parallel drawn between the way we gain electricity or water from a utility 
company. Just plug in and use what you want. Use of cloud computing 
may also have some benefits in terms of global and local environmental 
impacts – noting that Laudon and Laudon (2013, Section 5.3) report that 
in the USA data centres use more than 2 per cent of all electrical power. 
If cloud computer centres are located where hydroelectricity is generated 
and cheap, and data and work is sent to them using networks, then we 
may save the pollution of running computers on expensive electricity 
that is generated using carbon fuels (oil, gas, coal). As with most issues 
associated with global warming, greenhouse gases and CO
2
levels, green 
computing is a contentious issue with many different viewpoints.
Activity
Find and describe three examples of client-server computing. 
In each case, try to explain why this approach is used (for example, the benefits it brings) 
and what tasks (processing, data storage, etc.) are handled by the client and by the 
server. 
Research the benefits and problems of using a commercial cloud service to provide 
computing resources for a medium sized business. Think in each case (both for benefits 
and problems) about issues associated with cost, control, security and flexibility. Do you 
imagine that one day almost all computing will be provided in this way?