3.10 Introducing large ict systems into organisations

Introducing large ICT systems into
organisations
Part 1

organisations

In the next lesson we are
learning…
how Distributed Systems can be used
OBJECTIVES: OUTCOMES:
ALL WILL EVIDENCE
Read/listen/contribute to the Your teacher has noted your
discussion on Distributed Systems contribution, handout notes have been
read.
MOST SHOULD
Answer the sample questions EVIDENCE
Questions have been attempted
SOME COULD
Complete the homework task during EVIDENCE
the lesson Case Studies have been summarized,
text book questions answered.

At the end ask yourself: Do I understand the
advantages and disadvantages of Distributed
Systems, and therefore why they are used or not?

Distributed Systems
 Large companies usually have their own custom built IT systems
(British Airways, NHS, IKEA, DELL, HP)
 Smaller companies (customers) can be invited to use these systems,
to perhaps make orders, track inventory, send data, make
bookings/reservations, etc (Travel agents, doctor surgeries, web
users, etc)
Advantages for smaller companies Disadvantages for smaller companies
•Cheaper system since costs are •Little control over the system
shared •Less likely to look for other
•Guaranteed to work since the solutions, especially is a long term
larger company built it, and contract has been signed
perhaps other smaller companies
are already using it
•There is usually a forum/support
Advantages for larger companies
group of other users of the system Disadvantages for larger companies

•Lock customers into contracts •Increased cost of support
•Control over the system •Increased load on
servers/networks
•If the system goes down, then
customers will be unhappy, and
organisations
loss of revenue

Examples
The hospital has a system for reserving beds, operation
scheduling, testing, drug distribution, ordering of supplies,
timetables for companies can access this system to conduct
Many smaller nurses, etc
business, make reservations, order drugs, check timetables
etc
I can log in to book
a bed for a patient
of my surgery

I can access the system
I can log in to see if
to request a test to be I can log in to see what
the hospital has
conducted on a blood drugs the hospital needs,
room for my
Introducing large ICT systems into I can send them (and
sample so
emergency patient
organisations invoice them)

Examples

Newsagents will use the New
York Times Distributed System
to:
•Change the number of
newspapers they want to order in
the coming days
•Enter the number of newspapers
they have not sold (they do not
pay for these)
•Look up how much money they
owe the NYT
•Check delivery schedules
•Arrange for non sold
newspapers to ICT systems into
Introducing large be collected
•Manage subscriptions
organisations

Sample Questions
 1. You are starting up a new computer shop. You have a
choice of suppliers for the hardware you will sell. Only one
uses a Distributed System that they will provide for your use.
 A) What advantages for your shop does this Distributed System
offer? (4 marks)
 B) If you use this system, what are some disadvantages? (4
marks)
 List some of the things you would expect you could do with such
Answer A:
a distributed system. (4 marks)
•Cheaper to set up than creating your own system (1), so the computer shop can
spend cash elsewhere (1)
•The system would have been tried and tested by other computer shops (1), so from
day one of use the new computer shop will know it works (1)
Answer B:
•The supplier can control the system (1), so if there are issues, you will depend on the
supplier to fix them (1)
•The system is cheap and easy to get started, so the new computer company is less
likely to bother to hunt out better/cheaper/faster suppliers (1), which means the new
computer company may not be getting the best deals/hardware/service (1)
Answer C:
•Order hardware, review past orders, check prices, look up invoicing, make payments,
apply to return faulty goods, track orders, lookup technical specifications of hardware,
gain access to the latest hardware, download updates/patches (max 4 marks)
organisations

Homework
Read “AQA ICT for A2 Level pages 147 – 150 (top)
1. There are 3 case studies. Summarise the first two,
including:
 Name of organisation/s
 What the distributed systems does
 Answer all questions on each case study.

organisations

 Name of organisation
 Smith‟s News PLC
 Allows Smith‟s to deliver 60 million newspapers and magazines a week to
customers.
 The system allows for the tracking of newspapers/magazines from the
publishers to the warehouse and then to the retailers.
 It also assists in the repackaging of stock for distribution to retailers
 Allows wholesalers, publishers, and retailers to log in and use tracking
and/or ordering systems (run by NewsWorks – a part of Smith‟s)
 Generally the system allows for a more efficient method of
tracking/ordering publications
 “Why is it an advantage for a newspaper publisher to use NewsWorks‟
order processing and tracking system rather than to develop one of their
own?”
 There are a few reasons:
 The system is already set up (1) and so probably has been tried and
tested for a long time (1)
 It will be a lot cheaper (even free!) to use the system that is provided
(1), rather than build a bespoke system (1)
 There should already be Support Desk/Forum/Online help on the
organisations

 Name of organisation
 The NHS
 Allows authorised medical personnel to access patient clinical data and
general statistical information
 Patients can use the Choose and Book system to select the place and
time of their next appointment
 An electronic prescription system allows drugs to be sent from prescribing
doctor to pharmacy of choice so patient can easily collect it
 1. Some people feel that the new systems could cause a threat to
patient privacy. Can you justify their concerns?
o The system is accessed all of the country. It depends on staff
keeping their personal login and password details secure (1), so all
it takes is for one authorised user to leave their details lying around
for someone to see, or to not log off/lock computer when not using it
(1)
o The personal health data of patients in stored in electronic format,
so it can be copied, backup media lost, intercepted in transit from
server to pc, or even maliciously deleted/tampered with. (1)
o (Imagine if health insurance companies got hold of the data!)
Introducing large ICT statistics used in the system, is all identification of individuals
o In the systems into
organisationsremoved? (1)

o Discuss the advantages of the Choose and Book system to the
patient.
• Hospitals/clinics closer to home can be selected (1). Therefore the
patient does not have to travel so far (1), which can save them time,
money, distress, effort (1)
• A convenient time can be selected (1), which fits into the schedule of
the patient (1)
o What are the benefits of the electronic prescription system to:
• The GP Surgery
• Electronic orders = less paperwork (1), so more time can be spent
treating patients (1)
• Orders are transmitted instantly (1), so patients are treated quicker
(1) which reduces the number of return visits, and increases
reputation of surgery (1)
• The pharmacy
• Orders are delivered electronically (1), so there is less paperwork
and more time can be spent dispensing prescriptions (1)
• Higher likelihood of repeat orders since the their business is
available in the NHS system (1), which increases profits (1)
• The patient
• Can elect a pharmacy where the prescription will be collected (1)
Introducing large ICT systems into convenient (1)
so it is more
organisations

In the next lesson we are:
researching the NHS and the features of the Large
Scale System it introduced
ALL WILL EVIDENCE
Select one of 2 topics to research A topic has been selected

MOST SHOULD EVIDENCE
Use the Internet to research the stated At least 3 Internet sources have been
topic, and collect information on it identified, and the information
(bullet pointed) contained summarised

SOME COULD EVIDENCE
Convert the bullet pointed notes into Essay has been written and submitted
an essay worth 10 marks

At the end ask yourself: Could I produce 5
paragraphs of work on my chosen topic?

Systems
Since 2005 the NHS in the UK began working to introduce a Large Scale
System to maintain all health data on patients, and make it available to those
that need it. There are valid reasons for attempting such a large scale project,
however it has not been as successful as it could have been. Select one of
Whytopics below, and performLarge research on it.
the the NHS needed a new some Problems the NHS has faced in
Scale System attempting to introduce a new Large
Scale System
For each reason: For each problem identified:
•Original Problem •Original Problem
•How new NHS system would improve •How new system tried to solve it
this •Problems faced
•Who benefits from this improvement? •Criticisms
•URL where you found this information •URL where you found this information
•Date of article •Date of article
•Your opinion •Your opinion
(start at www.connectingfor (start at http://www.computerweekly.com)
health.nhs.uk)
This is an excellent exam question/essay worth 20 marks. Plenty of opportunities to earn
marks for stating :
•Reasons why a Large Scale System would be introduced (5 marks)
•Examples (from NHSNHS) (5 marks)
•Problems faced when introducing a Large Scale System (5 marks)
•Examples (from NHS) (5 marks)
organisations

Links to articles about NHS IT
 Article 1 – Information System Failures and the NHS http://goo.gl/8bILr
 Article 2 - Six reasons why the NHS National Programme for IT failed http://goo.gl/y4jZB
 Article 3 - Three reasons why NHS privacy and data-handling should be an election issue
http://goo.gl/A3Jxh
 Article 4 – Wikipedia article on “NHS Connecting for Health” http://goo.gl/H8WvQ

Links to articles about General IT
projects in UK
 Article 1 – UK wasting billions on IT projects http://goo.gl/MLdC1

organisations

When testing is incomplete, a real
disaster can occur!

organisations

organisations

Sometimes implementations of Large Scale
Systems are not successful. This can be for
many reasons. design of these are:
Poor analysis Poor Some Incomplete
testing
Lack of training Lack of staff Incompatible
components
Hardware changes before the project is completed

Links to articles on software failures
 20-famous-software-disasters -
http://goo.gl/ZSEMm
 Top-10-it-disasters-of-all-time - http://goo.gl/0QIb2

organisations

System What was it supposed to Cause of the problem Cost?
do?
What went wrong?

UK Bring the Passport Agency 1. Staff not trained •Millions of
Passport into the modern age, 2. Lack of testing Pounds
system speed up issue of 3. New law introduced that •Reputation
1999 passports increased demand for
BUT passports

Airbus Assist in the building of the
A380 new Airbus A380 plan
Design BUT
Software
issues
2006
Mars Travel to Mars and land on
Climate the planet
Observer BUT
1998

organisations

learning about the types of testing required for large
scale systems
ALL WILL EVIDENCE
Read the notes on Testing Notes are read

MOST SHOULD EVIDENCE
Create bullet point summary notes A word document of notes has been
generated
SOME COULD
Create a Power Point Flow Chart EVIDENCE
summarising the testing of large scale Document is created and printed
systems

At the end ask yourself: Could I produce 5
paragraphs of work on my chosen topic?

Reliability and Testing
Whenever a new system is developed extensive testing must be planned and
carried out. Often teams of people are involved. This can be the most
expensive phase in the development of software!
This chapter is about Large Scale Systems, however do not forget the following
for all systems:
TYPE OF TESTING
•Module testing Both small
•Functional Testing (or Black Box systems and
testing) Large Scale
•System Testing (or Alpha testing) Systems need
•User Testing (or Beta testing) these tests
•Operational Testing
However in Large Scale Systems more attention needs to be paid to certain test
types, and there are even a few extra tests to perform! These are mostly to do
with :
•Testing the system works on a network
•Testing the network still works with the system on it
•Testing the system works with many users at once
There are companies who will actually test software for developers. This can
work out cheaper than doing it in house. Utest is a company that tests Mobile
Phone Apps for developers. Click HERE for more info.
organisations

Reliability and Testing task
From Nelson Thomas AQA A2 text book :
•Read pages 72-75 on 7.2 Reliability and Testing
•Create summary (bullet pointed) notes on:

 To ensure large scales systems always operate as expected, the
following 4 categories of tests are completed:
 Functional tests:
 Performance tests:
 Usability tests:
 Security tests:
 Designing testing to ensure reliable operation
 Requirements based testing
 Program testing
 System testing
 Regression testing
 Change control
 Alpha testing
 Beta testing
 Testing network based systems
organisations

Reliability and Testing task
From Hodder AQA A2 text book :
•Read pages 150 - 153 on Reliability and Testing
•Create summary (bullet pointed) notes on:

 Developer testing
 Code walkthrough
 Functional testing
 Automated testing
 Surviving unusual events
 Compatibility testing
 User Acceptance Testing
 Testing network systems

organisations

Testing Systems

Functional Testing System Testing
Module Testing (aka Black Box (aka Alpha
testing) testing)

User Testing Operational
(aka User testing) Testing

organisations

learning about the types of testing required for large
scale systems
ALL WILL EVIDENCE
Identify reasons for why a large ICT I can state at least 5 reasons why a
System development might fail development might fail

Identify 4 areas that should be looked I can state the 4 areas
at when testing to ensure the system
operates as expected

Research and understand the different A concise definition of each type of
types of testing carried out on large testing is presented and remembered
scale ICT systems by all (testing required)

Why might a large ICT System
fail?
 Poor analysis of the initial problem
 Poor design of the intended solution
 Lack of training offered before implementation
 Lack of support provided during the
implementation stage
 Lack of staff
 Incomplete components
 Hardware changes before the project is
completed
 Poor testing (e.g. incomplete testing, getting the
wrong people to test it)
organisations

List at least three corporate
consequences of system failure

 Any business that loses its computer data will face
financial loss
 If the computer system is not working, they will not
be able to process transactions which are at the
heart of the business (loss of trade)
 Repeated failure is likely to lead to a company being
forced to stop trading
 Customers may lose confidence
 May lead to a poor reputation

Testing of Large Scale Systems

organisations

Testing
This chapter is about Large Scale Systems, however do not forget the following
for all systems:

TYPE OF TESTING
•Module testing Both small
•Integration systems and
•Functional Testing (or Black Box Large Scale
testing) Systems need
•System Testing (or Alpha testing) these tests
•User Testing (or Beta testing)
•Operational Testing

organisations

Task 1
 You have 15 minutes
 In groups you must:
 Create 1 slide per test type (there are 6 types)
 On that 1 slide you must
 Put a title which should be the name of the type of
test
 Write a short definition of that type of test
 Deligate in your groups however you like BUT
you must ALL know the definitions of each (you
will be tested)

organisations

Task 1
 The testing types are:
 Module Testing
 Integration Testing
 Functional Testing
 Systems Testing
 User Testing
 Operational Testing

organisations

Tell me about Module Testing

 Also known as unit or component testing
 Involves testing each individual section of the
software
 Written from a programmers perspective
 An example of white box testing

Tell me about integration Testing
 Where modules are combined one at a time and
debugged

Tell me about functional Testing

 Tests the operation of the system
 Written from a users perspective
 Example of Black Box testing (does a given input
produce the correct output?)

Tell me about System Testing

 Tests the complete integrated solution
 Tests that transactions are processed correctly from
beginning to end

Tell me about User Testing

 Where actual users test the system
 User documentation must also be tested at this
stage

Tell me about Operational Testing

 Conducted in the environment in which the solution
will be working or a simulated version

Testing large ICT Systems is a complex task what 4 areas will be looked at
when testing to ensure the system operates as expected?

 Functional defects – errors in the system that effect
the accuracy of the output

 Performance defects - errors in the system that
effect the speed of input, process and output

 Usability defects – Errors in the aesthetics/
structure/layout/navigation of the system which
means the user can‟t used it effectively

 Security defects – errors in the system which means
users can intentionally/accidently gain access to
restricted areas/data

Task 2
 You have 25 minutes
 In groups you must:
 Create 1 slide per test type (there are 9 types)
 On that 1 slide you must
 Put a title which should be the name of the type of
test
 Write a short definition of that type of test
 Deligate in your groups however you like BUT
you must ALL know the definitions of each (you
will be tested)

organisations

9 Types of Testing

 Client requirements – based testing
 Program testing (similar to code walkthrough)
 System testing
 Change Control
 Alpha Testing
 Beta Testing
 White Box Testing
 Black Box Testing

What testing techniques can be used when testing large ICT
systems and what people are involved in each technique?
 Testing team should be involved in writing the requirements to ensure that each can be tested

 Program testing (similar to code walkthrough)
 In development teams the code is read through against a checklist of common problems (Debugging programs could also
be used)

 System testing
 Following the test plan and using normal, erroneous and extreme data to test the whole system processes the input and
provides the correct output

 Re-running earlier tests once changes have been made (making sure the change in code hasn‟t had a knock on effect
and broke something else)

 Change Control
 Making sure that any changes happen in a controlled and coordinated way and well documented (must assess the
impact on all parts of the system)

 Alpha Testing
 Carried out by the software house, based on the test plan (users may have input). Results may require modifications until
the system is reliable enough to be tested by a wider audience

 Beta Testing
 Software being tested by a selected group of real users who use the system under normal conditions. Will report back
with any problems, which will then be resolved before final release

 Whit Box Testing
 Testing of the program by people familiar with programming (programmers). Checks the program code is written correctly

 Black Box Testing
 A technique used by people who never look at the programming code. They look at the output produced and check if the

Tell me about Client requirements – based
testing

 Testing the system against the client requirements
 A type of Black Box testing
 Testing team should be involved in writing the
requirements to ensure that each can be tested

Tell me about Program Testing

 Where the code of the program is read through and
tested
 A type of White Box testing
 Often done in teams
 Also referred to as a „Walkthrough‟

Tell me about System Testing

 Tests the system against the specification
 Uses normal, erroneous and extreme data to test the
whole system processes the input and provides the
correct output

Tell me about Regression Testing

 Re-running earlier tests once changes have been
made, making sure the change in code hasn‟t had a
knock on effect and broke something else.

Tell me about Change Control

 Making sure that any changes happen in a controlled
and coordinated way and well documented (must
assess the impact on all parts of the system)

Tell me about Alpha Testing

 Carried out by the software house
 It is based on the test plan (users may have input).
 Results may require modifications until the system is
reliable enough to be tested by a wider audience

Tell me about Beta Testing

 Software being tested by a selected group of real
users who use the system under normal conditions.
 Will report back with any problems, which will then
be resolved before final release

Tell me about White Box Testing

 Testing of the program by people familiar with
programming (programmers).
 Checks the program code is written correctly

Tell me about Black Box Testing

 A technique used by people who never look at the
programming code.
 They look at the output produced and check if the
requirements are met

Testing network based systems (which most large scale
systems are) is vital.

 You must test:
 The effect of the new system on the running of the
network
 The effect of the network structure on running the
new system

 If testing a WAN it might be better to simulate this
so as not to cause disruption within the company

 Testing a network based system requires
specialist skills and facilities

Installation of Large Scale
Systems

organisations

There are 4 different methods for installing a new
system into a workplace, what are they?

 Direct Changeover
 Phased Changeover
 Pilot Running
 Parallel Running

10.12 Explain the concept of a Direct Changeover and
identify the advantages and disadvantages of this
method

 Direct Changeover
 Old system stops, new system starts

Advantages of Direct Changeover Disadvantages of Direct Changeover
•The quickest of all the methods (As long •Difficult to train staff as the new system is
as it works) not available beforehand
•Less risk of staff being confused between •Stressful for users if not trained
the old system and the new one •Stressful for system developers (small
window to implement this changeover,
transfer data etc.)
•Very risky method, if new system doesn‟t
work, nothing to fall back on

10.13 Explain the concept of a Phased Changeover and
method

 Phased Changeover
 New system is brought in stages, each stage replacing part of the old system e.g. of a new
school management system introduce just the attendance par of the system, then maybe the
reports, then monitoring etc.

Advantages of Phased Changeover Disadvantages of Phased
Changeover
•Very structured, allows for each phase to •Slower than direct changeover
be fully evaluated before introducing the •Complete system can not be evaluated
next one until all phases are implemented
•Less risky than direct changeover •Integrating each phase of the new system
•Staff can be trained as each phased is with the old can be complex
introduced rather than everything all at
once

10.14 Explain the concept of a Pilot Running and
method

 Pilot Running
 New system replacing the old one but only on a small scale e.g. a single branch might use it, or
a particular department before being introduced and used by everyone

Advantages of Pilot Running Disadvantages of Pilot Running
•Much easier to control as a pilot can be •Slow to roll out
halted at any time •Pilot may not show problems that exist in
•Easy to monitor and evaluate (can full scale
compare to old system still running) •Organisation will be running two systems
•Easy to train staff by using pilot system at one time
as a training system
•Low risk if fails

10.15 Explain the concept of a Parallel Running and
method

 Parallel Running
 Old system and new system running alongside each other but working independently

Advantages of Parallel Running Disadvantages of Parallel Running
•Easy to compare to old system (is the •Very expensive method (duplication of
new system out performing?) staff and hardware)
•Lowest risk as old system can still be •Staff may get confused by having to
used if new system fails remember two sets of different procedures
•Staff can be trained gradually

We‟re developing a large system, we know documentation is
required. What documentation is required and who requires it?
 System documentation
 For the programmers who will maintain the system

 User Documentation
 For the users so they can operate the system

 When any new system is installed new users will
need to be trained!

 Change Logs
 Used to document the changes in versions
 E.g. Twitter and Facebook use them for their API
development to document when changes were made
and the versions

When handling the installation of a new system it is very
important to consider the resources you have available
to you, why?

 Existing infrastructures might support or negatively
effect the installation

 Existing hardware might be of use or need replacing

 Existing software might support the planning process
or hinder the compatibility

 Financial issues might restrict installation choices or
training

 The people you have available might have the
technical expertise to carry out the installation
themselves

Backup and Recovery involved with
implementing large scale systems

organisations

What are the potential threats to data in a
large scale system

 Inappropriate usage of devices
 Network data breaches
 Laptop Loss/Theft
 Lack of Education
 Natural disasters
 Sabotage/Terrorism

What is the purpose of producing file
backups?

 To make sure that if data from a computer system
is lost or corrupted for any reason, the files can
be recovered and the computer system restored.

What strategy do companies put in
place to avoid data loss?

 A disaster recovery strategy / backup and
recovery strategy

What factors should be considered when
devising a disaster recovery strategy ?

 The best time to backup
 How often to back up
 The type of backup to use
 Whose responsibility it is to backup
 The media that will be used
 Where the backup media will be kept
 A log of backups taken
 Testing the recovery of backed up data

What is the first stage in setting up a
disaster recovery strategy?

 Risk Analysis

What is the purpose of risk analysis and
what does it involve?
 Used to identify the main elements of the information
system

 A value to the business of each element is assigned

 Any threats to that element are then identified

 The likelihood (probability) of such threats occurring are
then established

 The speed with which that piece of data needs to be
recovered

 The severity of each element is then clearly established

What are the contents of a disaster
recovery plan?
 Alternative computer hardware
 If hardware is damaged what alternative is in place?

 Backup procedures
 What type of backup method and media will be used?

 Recovery Procedures
 What is the plan/order for restoring data?

 Staff responsibilities
 Who is responsible for doing what?

 Alternative working location
 If the building is damaged what is the solution?

Full, differential and incremental backups are methods which can
be used to backup data, explain each of these

 Full backup
 All data stored is saved

 Differential backup
 Saves only data that is different from the last full backup is
saved

 Incremental backup
 Saves all of the files that have changed since the
last backup whether that be full, differential or
incremental

There are alternative backup options available
for large scale systems.
 Your homework is to find out about these 6
alternative methods:

 Failover systems
 Replicated systems
 Regular snapshots
 Periodic backup
 Tape Backup
 Archiving

for large scale systems:
 Failover systems
 If a server fails it is setup to automatically switch over to an alternative server
 The server will pickup the service from the point at which it failed
 Users a „heartbeat‟ cable (If the heartbeat dies the changeover occurs)
 Vital for e-commerce

 Replicated systems
 Used on databases
 As data changes in the database a replica is automatically created in case of failure
 Provides quick recovery

 Regular snapshots
 Frozen image of a file system at a given instant of time
 Backup several times a day
 Does not require large amounts of storage
 Short backup windows

 Periodic backup
 Backup to a separate hard disk at intervals
 Can be full, incremental, differential

for large scale systems:
 Tape Backup
 Still regularly used
 Uses data tape drives and disks to backup
 Tapes can be taken off site

 Archiving
 Useful for backing up data
 The data that is achieved may not be needed
immediately
 Data that has not changed for a long time is still
accessible

Procedures for recovery of large scale systems is essential, they provide
guidance and actions for restoring the system. What procedures / steps
should be followed when restoring a large scale system?

 Step 1 – Estimate the situation
 Evaluate the extent of the problem, the likely case of failure and the amount of data lost
 Identify the state of the backup copies

 Step 2 – Evaluate available resources
 Human and hardware
 Make sure expertise is available
 Make sure there is sufficient hardware

 Step 3 – Set up
 Install „good‟ hard disks into functioning hardware, check power supplies and cabling

 Step 4 – Recovery run
 Install data recovery software and run it

 Step 5 – Evaluate the results
 Undertake a manual review of most important files

 Step 6 – Clean up
 Remove any corrupt files

For each element of data in an information system that needs to be
recovered an RTO is established, what is this?

 RTO stands for Recovery Time Objective.

 It defines the maximum time allowed to reload
recovered data and get the system fully
operational again.

For each element of data in an information system a Data
Recovery Point needs to be established, what is this?

 A Data Recovery Point is the last point at which
data can be recovered i.e. the time lapsed
between backups

 E.g. If the data is backed up overnight, the Data
Recovery Point is last night and there is the
potential to lose 24 hours worth of data.

 Reducing the RTO is expensive so it is important
to balance the importance of the data against
potential cost

Rearrange this diagram to show appropriate backup methods and
RTO‟s (Recovery Time Objectives)

C
o
Need Protecting
(Records)
• Periodic back up to disk s
R t
e
• Failover systems that pick up
c Near Critical O
o
operation instantly and
(Databases) f
v automatically
e P
r Important • Archive r
y (File systems) • Back up to tape o
T t
i • Replicated systems for quick e
Mission Critical
m recovery c
(E-Commerce, Email)
e • Regular data snapshots t
i
o
n

Rearrange this diagram to show appropriate backup methods and
RTO‟s (Recovery Time Objectives)

C
o
• Failover systems that pick up s
Mission Critical
(E-Commerce, Email)
operation instantly and t
R
e
automatically
c
• Replicated systems for quick O
Near Critical
o (Databases)
recovery f
v • Regular data snapshots
e Important P
r (File systems) • Periodic back up to disk
r
y
o
Need Protecting • Archive t
T
(Records) • Back up to tape e
i
m c
e t
i
o
n

There are 5 possible accommodation solutions
for large scale disasters i.e. fires, what are
these solutions?
 Use existing accommodation (if equipment is destroyed but the
building isn‟t, replace the equipment)

 Alternative accommodation (If the disaster has destroyed the building
and the system, alternative accommodation is required)

 Reciprocal site (Arrangements may have been made with a similar
organisation that have a similar system)

 Standby site (Is dealing with sensitive data a company might have a
complete and up-to-date second system installed at a different
location *See next slide)

 Contract with specialist disaster recovery company (Provide
accommodation and equipment if and when necessary, still can be
expensive)
The appropriate option should be
considered and included in the disaster

There are two types of standby sites,
what are they?

 Cold Standby site
 Duplicate system
 Tested on a regular basis
 Not used unless there is a disaster

 Hot Standby site
 The duplicate system is up and running as a „mirror‟
site
 Processes the same live data as the main site(s) at
the same time

Maintenance of large scale systems

organisations

It is important to carry out maintenance once a system
has been installed. What 3 types of maintenance are
there?

 Corrective maintenance
 Putting right any reported errors once the system is
operational

 Adaptive maintenance
 Altering the system to meet new organisation,
legislation or security requirements

 Perfective maintenance
 Where any inefficiencies are tweaked i.e. make the
system even better

Name two types of models that can be followed
when providing maintenance
 Quick fix
 Identify the problem and fix it as quick as possible
 No consideration to the long term effect
 Not ideal for large scale systems

 Iterative enhancement
 Has 3 stages
 System is analysed
 Proposed modifications classified
 Changes implemented

3.10 Introducing large ict systems into organisations

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3.10 Introducing large ict systems into organisations