Topic 1— Systems in organizations (10 hours) - COMPUTER SCIENCE Middle & High School

An embedded system This is a system where the software controls a hardware device and is embedded in that device. Issues in embedded systems typically include physical size, responsiveness, power management, etc. The example software system to control a medical device
An information system This is a system whose primary purpose is to manage and provide access to a database of information. Issues in information systems include security, usability, privacy, and maintaining data integrity. The example a medical records system.
A sensor-based data collection system This is a system whose primary purpose is to collect data from a set of sensors and process that data in some way. The key requirements of such systems are reliability, even in hostile environmental conditions, and maintainability. The example a data collection system at a wilderness weather station.
Systems for modeling and simulation These are systems that are developed byscientists and engineers to model physical processes or situations, which nclude many, separate, interacting objects. These are often computationally
intensive and require high-performance parallel systems for execution
Interactive transaction-based applications These are applications that execute on a remote computer and that are accessed by users from their own PCs orterminals. Obviously, these include web applications such as e-commerce applications where you can interact with a remote system to buy goods and services.This class of application also includes business systems, where a businessprovides access to its systems through a web browser or special-purpose clientprogram and cloud-based services, such as mail and photo sharing. Interactive applications often incorporate a large data store that is accessed and updated in each transaction
Batch processing systems These are business systems that are designed to process data in large batches. They process large numbers of individual inputs to create corresponding outputs. Examples of batch systems include periodic billing systems, such as phone billing systems, and salary payment systems
Data collection systems These are systems that collect data from their environment using a set of sensors and send that data to other systems for processing. The software has to interact with sensors and often is installed in a hostile environment such as inside an engine or in a remote location

1.1.1 Identify the context for which a new system is planned

Teacher Notes

Before a system is designed, it needs to be identified what the system should do. To do this is the job of the systems analyst. He looks at the existing system and tries to observe how it works. This can be done using surveys, interviewing users, observing them or by tracing how information is handled by looking at the documents produced by it.

For this, the systems analyst has to factor in a number of things: what existing infrastructure from the existing system can be used? What requirements on hardware and software will the new system have? Are there any ethical issues resulting, for example will the new system make people unnecessary, leading to loss of jobs?

Data Collection

Questionnaires
Interviews
Observation
Current system documentation
User manuals

1.1.2 Describe need for change management

Teacher Notes

Without a proper plan on how the new system will be implemented once it is designed the change from the old system to the new one will not be successful. Many factors will need to be regarded:

End user training
User's reluctance to change
User acceptance testing
Type of change over ?

1.1.3 Outline compatibility issues resulting from situations including legacy systems or business mergers

Without a proper plan on how the new system will be implemented once it is designed the change from the old system to the new one will not be successful. Many factors will need to be regarded:

1
Legacy System – In computing, a legacy system is a technology, computer system, or application program, that may or may not be supported or available for purchase any more.
2
Merger – A combination of two things, especially companies, into one

Language differences
Part of business operating in a different country than host using an older version of a system
If an american and an European businesses merge, their unit systems need to be merged (one uses SI units, one doesn’t)
Businesses not using same software environment (Microsoft Exchange vs. IBM Lotus Notes)

1.1.4 Compare the implementation of systems using a client’s hardware with hosting systems remotely.

Software as a Service (SaaS): The client does not run its own computer system to handle operations, but lends servers from the software manufacturer that are managed and maintained by the software manufacturer. A great example is SAP.

Advantages

No cost in employing personnel to maintain system
Software manufacturer can provide help in cases of malfunction
Maintenance and updating managed by software manufacturer → they have staff that fully understand the system
Client enjoys the professional know-how of the software manufacturer

Disadvantages

Data security issues resulting from trusting your information to someone else (loss of control)
Host may be in a different time zone, so maintenance can happen at uncomfortable times
Because host is not the user itself, user feedback is harder to get

1.1.5 Evaluate alternative installation processes.

Teacher Notes

Direct changeover / Big Bang
Parallel running
Phased Changeover
Pilot running

1.1.6 Discuss problems that may arise as a part of data migration

Teacher Notes

File formats are another worry when concerning the issue of data migration and compatibility. Having the ability to read and write data in the same manner as before, following an improvement or change in a system, is almost certainly the fundamental aspect which is taken into consideration.

Incompatible file formats

Incompatible data structures

Changed units leading to misinterpretation (new system interprets temperature in °C instead of °F)

1.1.7 Suggest various types of testing.

Teacher Notes

esting is very important in developing a computerized system, as it tries to ensure that the system works as expected. A system that does not work as expected (it is buggy) greatly reduces productivity and end user satisfaction.

Testing is usually done in two stages: before the system is delivered and after it has been set up.
Testing in the first stage is often referred to as Alpha testing, while testing in the second stage is often referred to as Beta testing.

Alpha testing involves the engineers who develop the system testing it with data similar to real data while beta testing involves testing by real users with real data.

Unit Testing
Alpha Testing
Beta Testings
Integration testing
user Acceptance Testing

1-1-7_testing

User focus

1.1.8 Describe the importance of user documentation.

Teacher Notes

User documentation is a crucial part of a system as it is the document that explains the working of the system to the user. A well-made user documentation guides the user through using the system and thus increases productivity. If the user documentation is simple, system implementation can happen faster because users require less training to learn how to use the new system.

Users are non-technical people, they only need to know how to use the system. Therefore, the user documentation does not involve detailed explanations of how the system works.

User documentation supports computer system users, including both hardware and software. Good user documentation can ensure that users are quickly able to adapt to a new system. Documentation is an important part of software engineering. Types of documentation include:

Different Types

Requirements - Statements that identify attributes, capabilities, characteristics, or qualities of a system. This is the foundation for all that is implemented.
Architecture/Design - Overview of software. Includes relations to an environment and construction principles to be used in design of software components.
Technical - Documentation of code, algorithms, interfaces, and APIs.
End User - Manuals for the end-user, system administrators, and support staff.

1.1.9 Evaluate different methods of providing user documentation.

Teacher Notes

Help files: Files supplied together with the system. They can usually be called up with a button in the system.

Advantages

Accessible at any time when using the program
Give general instructions on how to use the system
Give general instructions on how to solve some major errors

Disadvantages

They can only be used after system has been installed. They don’t give any help when installing the solution
They often only deal with very general errors
They often lack a search capability, you have to look to find help for your problem

Online support: Special web service hosted by the system’s developer to provide user documentation.

Printed manuals: manuals printed on paper and supplied together with the system.

1.1.10 Evaluate different methods of delivering user training.

Training staff in using a new system is very important as productivity greatly depend on how familiar users are with a system. Therefore good user training is an essential part of introducing a new system.

Self-instruction: users reading a manual or watching a tutorial, or randomly doing something in the system to figure out how it works. This type of training is only suitable for experienced computer users as they are more confident to start using an unfamiliar system alone to figure out how it works.

Formal classes: users sitting in a classroom listening to an instructor who shows and explains how to use the system. This type of training is useful to train large amounts of staff as it is effective and relatively cheap, but if the size of the classes is too big, there is little time to deal with individual problems and questions.

Remote/online/personal training: an instructor training a single user either by being in the same room or by some kind of remote connection (Skype, chat). This is the most effective way of training as training can be suited to user’s needs and abilities, but is very expensive compared to other types of training.

System Backup

1.1.11 Outline the consequences of data loss in a specified situation.

Common Causes of Data Loss

Human Error
Viruses & Malware
Power Outages
Software Corruption

Computer Theft
Liquid Damage
Software Corruption
Hackers and Insiders

1.1.12 Outline the consequences of data loss in a specified situation.

Data Loss in Hotel Booking System

Example: A hotel recently implemented a computerized system to manage room reservations. Reservations can be made through the web-page of the hotel or via phone. All the reservations with customer, room and reservation details are stored in a database. After a while, one of the hard disks in the system fail

Had the hotel relied on storing reservation details only on that hard disk, all the reservations would be gone now and the hotel would have no way of knowing who had a reservation or how much each of their customers owed. They would also be unable to make more reservations until a new hard drive is acquired.

1.1.13 Describe a range of methods that can be used to prevent data loss

Regular back ups: By copying all sensitive information on to a different medium than the one used in the system, like a second hard disk or CDs, chance or information loss can be reduced significantly. By storing these media physically separated from the system, data loss due to malicious activities can be prevented as well. In the case of very sensitive information of large companies like Google, information is often duplicated on servers separated by large distances and in different climates to reduce the chance of data loss due to environmental causes such as tornado or earthquake.

Making hard copies: In some cases, information can also be printed out to be archived, like books, texts, important contracts or scientific papers. However, creating hard copies can be expensive and take up a large amount space. Hard copies are also liable to data loss, as in the case of print-outs getting burned in a fire.

Software Depolyment

1.1.13 Describe strategies for managing releases and updates

Students should be aware of a variety of ways in which updates and patches are made available and deployed. This includes automatic updates received on a regular basis online

1.1.14 Describe strategies for managing releases and updates

Automatic updates: the system checks automatically for updates over the internet from time to time. If updates are available, they are downloaded and installed automatically.

Advantages:

Updates get installed automatically. Inexperienced users have an easy chance to get the updates.
No need for software manufacturer to contact every user about the new update

Disadvantages:

Users miss updates if they are not connected to the internet.
If updates bring a major change of system functions, users might not be informed about it

Manual updates: the software manufacturer contacts every user about the new update and supplies the installation package to him to be installed.

Advantages:

Users have more control what updates they want to install
Users get to know if an update brings major changes to how the system works

Disadvantages:

Users might miss an update fixing security issues
Users might not know how to install the update
Users might harm system by wrongly installing update
Users might lose the medium containing the update

Lesson 5 ( User Focus Documentation and Training )

Learning Objectives

Describe the importance of user documentation
Evaluate different methods of providing user documentation
Evaluate different methods of giving user Training

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Information Technology in a Global Society IB

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Legacy System Definition

A legacy system is a computer system that is no longer available for purchase or is no longer supported by the manufacturer. A legacy system might be just a few years old, or it could be decades old. Some legacy systems may operate on (and even require), certain very old hardware which is no longer available. Others may only run on older operating systems and not be compatible with modern versions. Sometimes the manufacturer of a legacy system no longer exists, and in other cases the manufacturer has dropped support in favour of more recent products. This usually means updates and security fixes will not be available for the system, which can be a significant problem for organisations.

SDLC-case-examples

IB DP Computer Science Notes by Madeline