Topic 6

• computer/hardware faliure
• deliberate damage
• accidental damage
• theft
• fire
• hacking
• terrorist attack
• natural distasters
• viruses
• software bugs
• power cuts

malprcatice is improper , careless or unprofessional conduct. this means that someone who forgets to log off the network allowing others to see and use their computer would be guilty of malpractice but not crime.

 a crime is an illegal act. when a crime is committed the person is punishable by law normally by a fine or imprisionment exapmle of crime are

• passing on sesitive data  - data protection act 1998
• hacking into a network - computer misue act 1990
• illegally copying software - copyright act 1988
• spreading computer viruses

malicious damage can arise from inside or outside the organisation and can involve altering a program so it does not work properly, or a person deliberltey introducing a virus. 

viriues pose a main threat under malicious damage. a virus is a program that replicates itself automatically and carries with itsome payload which causes damage.  once a computer has a virus it is said to be infected 

virsues can 

• display annoying messages on the screen
• delete prgrams or data
• use up resources

way viruses can be spread

• external email/ internal
• shared disk
• downloads from untrustes sites
• clicking on banners and advertisments

• installvirus checking software
• do not open emails from unknown sources
• keep virus checking software up to date
• train staff to be aware
• do not open file attachments unless from trusted source

back up means making copies of software and data so that the data can be recovered should there be a total loss of the ICT system.

backup  involve the creation of data and programs so that if the data or programs are damaged or lost they can be recreated from the abckup copies.

backups should be taken regularly an on a routine basis and copie should be kept off site. or in a fireproof safe to protect from psooible damage 

there are a number of online back up service where you can back up your files online using the internet and you can pay for extra storage space. e.g the cloud. 

procedures for backup 

• use a different tape or disk each day 
• make one person responable
• keep backups safe 
• reherse backup recovery.  - manually scheduled. 

this is a plan for taking backups  and also recovers the recovery of data 

the strategy depends on 

• what - what needs to be abcked up 
• when - how often 
• how - how it is backed up
• staorage.

full backup

making a copy of all the files on the system

Incremental Backup

this type of back up backs up the files which have changed snce the last full back up. if the files corrupt four days after the back up there will be four different set with the changes on them. 

Differential Bakcup

a Differential backup is a cumulative backup of changes made since the last full backup. the system adds further data that has changes since the last full backup 

• storage capaicty needed
• portability
• speed of data transfer
• speed of access
• ability to connect to different computers or other deivices

Recovery Procedures are those that are put in place order to get the ICT system working again. there must be a tried and tested plan to get everything working again: here are things to be considered:

• alternative building
• availabilty of staff at a short notice
• abitity of hardware 
• training staff
• aletrnative communication line. 

RAID

many network systems use raid ( redundant array of inexpensive disk) system for the backup of data, basically they use a series of magnetic disk on which to store data . there are different raid systems and in one type the system will tskr over if orginal data is damages ot destroyed.

Clustering

to improve network security a texhnique called clustering is used, here file servers and storage devices are networed together so that the depenece of one file serve anf  one storage device is eliminated 

Fast Repetative Processing 

processare so fast that there are not many task that challenges them. fast repetitive processing is required in mny applications such as biling systems.

Vast Storage Capacity

the storage offered by ICT systems is almost limitless,storage is not very cheap and available in different forms e.g. ROM & RAM

Searching & Combine Data

the interent allows data to be recived quickly from different sources and combined together 

Improved Presentation Of Software

it is now very easy to obtain images using digital cameras, this means documents can be incororated into material such as documents and presentations 

Improves Accessibility to Information And Services

Ability to shop for groceries online is helpful for the old, using the internet you have a globallibrary and can access a range of information including news, maps

Improved Security Of Data And Processes

with a network security is centralised by 

• someone being given the responibility for taking backups, a single back up to back up all files. biometric securit can be used to check that only authorised people have access to ICT systems

Hardware Limitations

• Speed of Processor 
• Amount of main memory 
• large amounts of memory needed for multi tasking 
• limitations of peripherals
• reliabilty - not completely reliable

Commuication Limitations

• network Topology  - certain topologys can only contain a certain number of terminals
• Bandwidth - moe needed to run more programs
• Network has grown too big - run slow

Software Limitations

• Ability to transfer data - if one piece cannot be read it is a limitation
• Bugs - causes system to crash
• Compatability - you may not have an operation system able to run applications
• Poor software designs - causes fustration and stress

Inappropriate System Design

there are many projects that have been created that do not do what they were set out to do this is usally caused by

• inexperienced development teams
• lack of project managemnent
• lack of project control

Operations Procedures 

when a new ICT system is developed the developer has the choice of fitting in with the existing way of doing thing in the existing way or completely different. 

if the owner decides the ICT system will work around the same procedures thi will limi the new systems effectiveness

inappropriate Data Contril Mechanisms

Data control mechanism should be put in place by induvisulas or organisations to protect the data  here are some inaequate ways.

• No proper verification of validation
• no backup procedures
• no proper limits to acss

Batch Processing - the information is bathced together, the main features are no human intervention and batching of data, no gap between processing, large volumes of data, control/ hash totals are used e.g multiple choce test papers

Transaction Processing - processes each transaction as it arises exapmles are.

• an order being taken
• a customer making a payment
•  a flight being booke

there is constant interaction wioth person and computer, transaction is dealt with as soon as it occours, each transaction is completed before the next, ideal for booking systems

Real time Processing - the data is recieved by the system is processed immediately without any delay , real time is mainly used for control , examples are 

• games - where an immediate response is needed. 
• flight control - auto matic pilot where the computer takes of=ver using the input from the computer.