Protecting against viruses

Virus: A computer program that is planted in one computer and then transferred, hidden in useful information, to one or more other computers with the intention of corrupting or wiping out information in the recipient computer.

Viruses are extremely common. Many different types of viruses exist, ranging from ones that prevent you from opening up word-processed documents through to ones that destroy the entire contents of a hard drive. Viruses can be caught in several ways, for example by exchanging floppy disks, via electronic mail messages and through downloading documents from the Web. Networks make it much easier for viruses to move around. Once a virus gets into an organisation’s computer system it can spread very quickly. New viruses appear each week, so it is essential that users have up-to-date anti-virus software to combat this problem.

If users have software that is unlicenced it could mean that it is ‘pirate’ or ‘bootleg’ software. This is software that has been illegally copied. Software of this nature sometimes contains viruses that can be extremely damaging to computers.

Mainframe computing

Mainframe computing developed at a time when computational power was an expensive and scarce resource. In order to use the expensive computer technologies efficiently, organisations had to share their resources. Many of computerised applications, such as invoicing, purchasing, payroll, accounting and so on, involved the organisation as a whole.

If the original reasons for the mainframe computing model were cost and scarcity of resources, the current reasons for sharing computer power are

• security: the protection of data from outside or unauthorised access

• integrity: the guarantee that the data is not corrupted and that repeatability is achievable using the same applications and data

 system availability: centralised facilities can be operated by teams in shifts

24 hours a day, maximising the investment in IT equipment and allowing large

data processing activities to be carried out efficiently

 data sharing: data input or created in one part of the organisation becomes

available to other parts

• applications: many modern applications, such as personnel management systems, require access to a shared pool of resources.

Today, mainframe computing is no longer an expensive resource; sharing is still a cost -effective means of providing computational power. Recent studies have shown that on a per-user basis, mainframe computing provides the least expensive form of computing.

A mainframe environment involves not just the hardware. The security, integrity and availability of the mainframe system can only be achieved if the computer centre is staffed by people with the necessary skills, operated according to a set of practices and managed with the discipline (that is, the processes and procedures) that ensures the appropriate levels of security, integrity and availability. This is the ‘mainframe environment’.