Traditional PCs however commanded a great audience from enterprises to private institutions to personal users. They could store any type of data in any format and order. But, desktop PC hard drives had a limited lifespan of 5-8 years. The hard drives also had a limited storage space. They promised low data security and required high maintenance. But, they constituted great manufacturing rates. Desktop PCs constituted personal freedom to store data on the computer hard disks or even on removable data storage media.



These included floppy disks, DVD and CDs. The user could input these devices in any desktop PC to store data and then later retrieve the data on personal desktop PC. Even the transfer of data seemingly easy was marred with problems. Usually data stored on the PC hard drive had difficulty being copied onto another storage medium. Usually the data format and sequencing changed. This caused many users great stress. In addition, the traditional desktop PC was linked to a common server. This constituted the network neighbourhood. It meant that the failure of the server corrupted the entire neighbourhood of PCs. Thus, continuous uninterrupted data generation on traditional desktop PCs was questionable.

In the 1990s, IBM launched a new offshoot of the traditional desktop PC. This modification countered all the drawbacks and highlighted the strengths of a traditional PC. Seagate Technologies and Hitachi also followed modifying the structure and usability status of the PCD. Today, desktop PCs are no longer ungainly structures emitting great heat. Desktop PCs work on batteries and are portable. They are as thin as blades. They do not consume much electricity and are high on data security.

There are four classes of desktop virtualization today:

Single Remote Desktop -- This is a single desktop PC that is accessed remotely across a network connection using remote PC access software -- GoToMyPC, WebEx, PCAnywhere, Windows Remote Desktop, VNC and other similar methods.

Shared Desktops -- This model can be described as a multi-user server PC environment such as the Citrix, Ericom Software and Terminal Services. They are used to host many users who all "share" a common PC desktop environment on a server machine.

Virtual Machine Desktops -- These desktops use virtual machine technology to host multiple instances of a standard, single-user desktop PC operating system on a server machine.

Physical PC blade Desktops -- This is an individual "client blade" PC. It is used to host multiple independent user sessions, each one running on its own physical PC blade.

All these virtualized desktop models have their advantages and limitations. They are popular as they enable a user who simply needs direct access to a single PC machine's desktop from a remote location through a network, usually the Internet. Shared, VM and Physical desktops are generally used by organisations to host and manage numerous user desktops centrally. Desktop Virtualization is a rapidly spiralling industry driven by many different factors. This includes people's needs to work remotely i.e. tele-working, mobile sales, outsourcing, propelling companies to maintain control over their computing assets and intellectual property available on business desktops.

Running user desktops and applications provides significant value and benefits over the traditional local PC desktop model. These include improved security by keeping desktops in secure data centers, reducing management costs through centralisation and the ability to effectively share PC compute power across many users. In short, virtualised desktop computing consists of a keyboard and display. Most of the hardware resources and software programs would be centralized on servers in a secure data center. Virtual desktops guarantee greater control, better security, lower cost of ownership, less power consumption, enforced compliance with organisation policies.

The Blade desktop PC and the terminal desktop PC also boast of a high level of data security. In these PCs, one server has the capacity to host multiple virtual PCs. A virtual PC's screen image is sent to a user's desktop machine. The virtual desktop also has the ability to refresh the screen by checking desktop functions and typed data.