What is a client machine or device?
A client machine or device is simply a machine that connects to a server or service, examples include:
  • PC/Laptop
  • Apple Mac/Notebook
  • Linux machine
  • Thin client
  • PDA
  • SmartPhone
  • etc

From a software perspective there are different considerations depending on the nature of the device.

PC/Laptop - These are 'desktop' or laptop computers that run the Microsoft operating system Windows.  The operating system is the base layer of software that enables the hardware components to work together and communicate with software applications.

Windows compatible software applications (e.g. Microsoft Word, Adobe Acrobat etc) are then installed onto the machine, effectively on top of the operating system.

Apple Mac/Notebook - Apple license their software in pretty much the same way as Microsoft, except that when you purchase an Apple machine, the operating system comes as part of that machine.  Only when you upgrade an Apple to a later version of the OS do you have to purchase a new licence.

Applications sit on Apple machines in exactly the same way as Windows machines.

If a purchased licence is required for the application, then the licence must match the edition and version of the application that is installed.

Linux machines - Linux is the third main client machine operating system you might come across.  The OS is free to install as are many of the applications that have been developed for the linux environment.

Please note - Every piece of software on the planet that we are aware of can only be operated under licence, but you might not have to pay for that licence.  The Linux OS and most applications are released under the GPL2 or more recently GPL3 licences.

Some Linux applications will require licences to be purchased, so it is worth checking the licensing requirements whenever installation takes place.

More than one client machine
When organisations have more than one client machine usually a network is created so that machines can receive services, such as an internet connection or email.

These services are provided by servers.

We go into more detail on the next page - Servers - a similar model is used by Microsoft and Apple.

Microsoft provide software that is used to run servers, whereas Apple provide their own servers running Apple server software.

Please note - Each client machine of any of the above types that connects to a server that is running Microsoft software will require a licence for the connection (Client access licence - CAL) - Connections to servers - whatever the OS it is running, i.e Windows, Apple or Linux.

Thin client - Thin clients (or dumb terminals) are stripped down PC's.  They usually run a version of the Microsoft Windows operating system, but you cannot install applications onto them in the same way that you can a PC.

To use an application such as Microsoft Word, the user logs into the thin client and is given access to the application that is actually running on the server.

The idea is that they connect to a server (over the network).  The main point of thin clients is that the hardware is cheaper and easier to manage remotely.

You should always assume that all software accessed through thin client machines requires a licence in exactly the same way as if the software was installed on the machine.

Summary of where licence purchases are required
  • Microsoft PC/Laptop - Operating System, applications, connection to Microsoft servers
  • Apple Mac/Notebook - Operating System, applications, connection to Microsoft servers
  • Linux machines - Some applications, connection to Microsoft servers
  • Thin clients - Operating System, applications accessed, connection to Microsoft servers.
  • PDA/SmartPhones - Operating System (usually comes with the device), connection to Microsoft servers
Now we look at Servers...