Introduction

Unit 1

• 01. Health & Safety in Relation to ICT Systems
• 02. Analysis
• 03. Design of Solutions
• 04. Selection and Use of Input Devices and Input Media
• 05. Selection and Use of Storage Requirements, Media and Devices
• 06. Selection and Use of Output Methods, Media and Devices
• 07. Selection and Use of Appropriate Software
• 08. Implementation of ICT Related Solutions
• 09. Testing of ICT Related Solutions
• 10. Evaluation of ICT Related Solutions

Unit 2

• 01. An ICT System and its Components
• 02. Data and Information
• 03. People and ICT Systems
• 04. Transfer of Data in ICT Systems
• 05. Safety and Security of Data in ICT Systems
• 06. Backup and Recovery
• 07. What ICT can Provide
• 08. Factors Affecting the Use of ICT
• 09. The Consequences of the Use of ICT

6. Back Up and Recovery

The need for data to be backed up is very important, but it is surprising how many people actually save a back up of their work and suffer the consequences of losing it by accidental deletion or loss of the computer etc. There are many threats to an ICT system as explained in the last section (see topic 5).

Viruses can spread on a network by internal and external e-mails, sharing data on disks, memory sticks, from the internal intranet and from clicking on and downloading files from the Internet. Virus checking software programs will prevent a virus from operating if the software is kept up-to-date. This is normally done by paying an annual subscription to the Anti-virus company. Everytime a new update of the anti-virus program is available, it is released onto the Internet for the computer with a 'live' subscription to access and to download automatically. Organisations employing staff need to have a clear plan to prevent viruses entering the ICT system, because of staff carelessness or deliberate misuse. A procedure would have been devised for the running of the system, and a policy for staff to adhere to. Some of these policies may be:

Policy for ICT staff:

• Install up-to-date anti-virus software and ensure the subscriptions don't run out
• Have an e-mail policy about sending and receiving and what to do with attachments
• Training of staff as induction and refreshers in safe use of the ICT system
• Only allowing authorised software and programs on the system
• Not allowing staff to load any personal software onto the system

Policy for employees:

• To adhere to the rules about using the ICT system safely
• No unauthorised use of the Internet and downloading of files
• Only open authorised e-mails and only attachments from a trusted source
• Do not bring in personal software and load it into the ICT system
• Only log in to their own user account, use the software that they are allowed as part of their job
• Not to leave the workstation insecure or allow their password to becopied.

Even with policies in place there are still cases where data and software can be lost as stated above or in topic 5. Therefore there is a need for data to be backed up.

Viruses may be downloaded from the internet from a variety of sources. Most viruses do something from displayingannoying messages on the computer screen to deleting programs, using up computer time slowing tasks to sending information about your files to the originator of the virus. All computers should have a virus checker installed which is able to download the latest programs created to deal with the latest virus attacks.

A virus may be downloaded when a pop up is accessed in the hope that the user will want something for nothing. Viruses spread by opening infected e-mail; using the Internet or the company's own intranet by clicking on banner and pop up advertisements on the Internet; downloading music, video and gameson the Internet; and sharing disks and usb drives.

To prevent the chances of being infected by a virus individuals and organisations should do the following:

• have virus checking software installed on all computer workstations;
• keep the software up-to-date by subscription so that new updates are downloaded to keep up with the latest threats;
• have a policy which clearly explains to staff acceptable use and unacceptable use of the organisation's computers;
• have induction and regular training sessions and newsletters to make staff aware and to keep them informed of risks;
• not allow staff to bring in their own software on portable media;
• have a policy on the use of e-mails, where they have originated from and what attachments can be safely opened;
• have a policy on the type of software that can be downloaded from the Internet, such as music, video and games.

Back Up of Data.

Data is backed up (copied) and kept somewhere safe in case anything happens to the original data. Without data an ICT system cannot work. Data is usually the most valuable part of the ICT system and in some cases is irreplacible. As individuals we should all back up our work done on computers to another folder, or a removable device should anything happen. Of course it all depends on how important we think that work or data is in value, not just in collecting but time etc. There are software programs that do all the backing up for us, they just need installing and programmed to do exactly what we require them to do.

If an organisation looses all of its data the chances are that it will never recover and could go out of business very quickly. It is very important that organisations are able to save all of their data securely so that if the unthinkable happens the data can be restored and the organisation resumes business as fast as possible.

Back ups must be taken at regular intervals and in accordance with the organisation's Back up Procedure. The procedures should include:

• the location of where the copies are kept, (a secure fireproof safe on site, or better off site - safe from total destruction);
• the type of media to store the data on, (magnetic tape for large volumes of data, or usb drives, portable hard drives);
• the option of on-line back-up using the Internet, (stored on a server and usually encrypted access for security);

    Hard Drive                        Tape Drive                          USB Drive                             Optical Drive

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Procedures

• At the end of the day or cycle, select a new disk, if disks are rotated then select the oldest data disk to copy to;
• The network manager or the responsible person should be assigned the task of doing the back up disks;
• Ensure that the disks actually work by checking at regular intervals that data can be restored from the back up ddrive;
• Ensure that everyone knows the procedures for the recovery of data from back up to the system;
• Ensure that the back up drives are stored in an appropriately safe environment.
  

Schedules

• Back ups are usually done automatically with the software programed to do the back up task weekly or daily or hourly, depending on the nature of the data. This system of a specific time is also used for manual back up of data.

Master File and the Transaction File

• Used in large ICT systems where numerous transactions take place;
• The master file holds all of the data, the transaction file hold the new transactions for that particular day, in the cycle (usually each day), the transactions are transfered to the master file;
• There is a copy of the master file in case data is lost, the system is known as 'Grandfather, Father and Son System'.
• The oldest master file is kept with its transaction file - the 'Grandfather'.
• These two files then produce the new master file - the 'father'.
• The 'father' file and its transaction file produces the latest file - the 'son'.
• This is repeated each day or each cycle creating the need for only three generations of files.

Individuals and organisations have different needs from their ICT systems and will therefore have different strategies for backing up data. The strategy for backup and recovery requires:

• What needs to be backed up; individuals or organisations small or large; importance of the data;
• When does it need to be backed up; how often - every second or every month;
• How can it be backed up; depends on the amount that has to be backed up and how fast it would be needed;
• Where can it be stored; what method is decided by the media available, see the drives above.

Three different types of file backup

• Full backup: is a copy of all the files on the system.
• Incremental backup: is a copy of all the files that have changed since the last full backup. Where this is done daily and the full backup weekly, to restore damaged files the full back up will have to be updated with the incremental backup files for each day, starting from the day full backup was done to the current day.
• Differential backup: is a more advanced form of the previous where each incremental backup is added to make a cumulative back up. If the situation arose as above there would only be the need for a single backup to the full backup.

Responsibility for backup should always be assigned to one individual in an organisation's networked system, such as the network manager, the lead technician, someone with authority. An individual will backup work as and when required but the organisation should have a system of what, when, how and where to.

Procedures are a set of rules of ways of doing things, recovery procedures are ways in which the organisation can get their system up and running as normal in the least possible time after a system data loss. Recovery procedures will consist of:

• using alternative accommodation and hardware and communication lines should the existing site or part of that site be destroyed;
• the availability of existing staff and short term contract staff to implement the recovery, including the re-installment of the underlying system and application software programs;

In some cases the nature of the organisation requires that the system is running continuously. This requires even greater cost in ensuring the backup and recovery process is efficient enough to show no noticeable sign that propbems have occured. Consider on-line booking and ordering of services and goods, where the customer simply has to access another provider.

Computer systems may contain many server processors and on-line backup drives with high speed communication between them. Transactions are recorded simultaneously on more than one drive therefore if one fails another computer will take over with no time loss. Banks, airline and rail bookings are such systems that require to be constantly in use.

RAID - Redundant Array of Inexpensive Disks. A system that uses a series of magnetic (hard) disks that store data. There are many different systems but any failure of one disk can be rectified by another which has the stored data.

RAID 1 requires two hard drives. The controller will simultaneously write all information onto both drives, which means you have full data redundancy. Should one of the drives fail, the second one will still be there. After replacing the faulty drive, the controller will recreate the RAID 1 array.

If there are more servers then any server failure can be rectified by the second server etc.

Usually with RAID there are many disks linked to the server storing transactions, when it is time for the oldest one to incremental backup it is then used as the newest disk.

Check the Backup of Data slides.