Citrix Training


In this module, terminology is introduced to show what the technology involved is and what it actually does, starting from the basics and building up.

Personal Computers

The 'personal computer' or 'PC' for short has become an important part of the lives of many during the technical advances made in the past twenty years.

Personal computers are used at home, at work, in internet cafes to schools. These computers are used to run software such as word processors, spreadsheets, web browsers (such as Microsoft Internet Explorer, Mozilla Firefox, Google Chrome, Opera) to specialist business applications.


Personal computers can also be called workstations, especially in the workplace and generally have slightly more powerful specifications.

For the purpose of this course, workstations and personal computers will be known as desktop computers, as this is also another term used widely to describe personal computers.


Portable versions of desktop computers are known as laptops and these are designed to be powerful, yet provide this power on the move, with improved battery life in a smaller form factor. Laptops have become lighter over the years and this improved portability has made them more widespread.

Desktop Operating Systems

Desktop computers run desktop operating systems such as Windows XP, Windows 7 and so on. These desktop operating systems are designed to provide functionality for using software from word processors to web browsers.


There are other types of computers called 'Servers' which are computers with similar components to desktop computers such as a processor (to do the calculations, also known as a CPU - central processing unit) memory, disks (also known as hard drives) and these components may be more powerful than their desktop computer counterparts.

Server Operating Systems

What really separates the desktop computer from the server computer is the operating system which is used. On a desktop computer, we use desktop versions of Microsoft Windows including Windows XP, Windows Vista and Windows 7. Some desktop computers may have desktop operating systems from Apple to Linux desktop derivatives such Ubuntu, Fedora and Debian.

On the server, server based operating systems will be used, so for Windows, Microsoft Windows Server 2003 and Microsoft Windows Server 2008 are popular choices. If it's going to be a Linux based server, then Red Hat Linux is a popular choice.

These operating systems are designed to utilise the server hardware more appropriately than a desktop operating system would. Moreover, the server operating systems are designed to deal with multiple users, whilst a desktop operating system is designed to deal with a single user.

A server operating system would not ideally be used in the same way as a desktop operating system, that is, it is installed on a desktop computer and then used for software such as word processing.

This is like using a bus instead of a car, to transport a single person. It is just an overkill of the power available to do something which could be done with less.

Server roles

Servers can be configured to provide different roles, that is, a server can be assigned a particular duty to perform. So a server could be assigned the role of 'print server' and it would deal with printing, by sending print requests to the appropriate printers.

Servers could be assigned a 'file server' role and would therefore be involved in filing information (storing information on their disks) which can be retrieved when required.

Other server roles include email servers, web servers, database servers and authentication servers to name a few.


Server operating systems tend to operate in a client/server fashion, whereby the client, which is the desktop computer (as well as laptops and smart phones), connect to the server.

Depending on how the server is configured, the desktop computer user will be able to print, store their files, authenticate, send emails and so on using their connection from their desktop computer to a server.

A single server will tend to have many clients that is desktop computers (as well as laptops) requesting services from printing to email (subject to what service the server is set up to provide) from the server.

The services requested depend on what role the server is configured for, so if it is configured as an email server, it will send and receive the email sent from the user's desktop computer (as well as from laptops and smartphones).

Clients and Servers

The screenshot 'Clients and Servers', above shows several different clients, laptops, computers and smart phones connecting to an email server and a web server.

32-bit versus 64-bit

There's a lot of talk about 64-bit operating systems, as this is the next step in the evolution of computing. Without getting too technical, the difference between 32-bit and 64-bit operating systems is the amount of memory they can use efficiently.

32-bit operating systems can use directly 4 gigabytes (Gb) of memory, whilst 64-bit can directly access up to 2,000 gigabytes (Gb) of memory. This means in theory, more programs can be used on 64-bit machines. Only computers with 64-bit processors can use 64-bit operating systems.

We will only be using the 64-bit versions of operating systems in this course.


 • Servers are powerful computers running server based operating systems

 • Clients are desktop computers, laptops and any other devices which require services from servers

 • Servers provide services to clients such as printing, email etc.

 • Operating systems are software designed to allow people to use computers

 • Clients connect to servers for various services such as email

 • 64-bit operating systems can access more memory