Saturday, October 16, 2010

Storage characteristics and trends

Questions

1. What does 'random access' mean?
Random access means that any storage location can be directly read or written. It is also called 'direct' access.

2. What does 'sequential access' mean?
Sequential access means that the storage locations have to be read or written in their correct order, starting with the first location.

3. What does 'volatile' mean?
Volatile refers to storage devices that will lose all thier data if the power is switched off.

4. Why is RAM the only volatile storage device?
RAM is the only storage device that can described as volatile as it needs a contant power supply to keep its data.

5. Why are sequential access devices better suited for storing backup data?
They work at a slow speed. Although access times may be poor, the rate of continuously writing or reading data can actually be very fast.

Thursday, October 14, 2010

Storing and Retrieving hardware

RAM and ROM

RAM (Random Access Memory)- is needed in any system that needs to store new instructions and new data, or to change those instructions or data. RAM chips are primary storage devices found in every computer system.

The most common forms of RAM include:


  • DRAM (Dynamic RAM)- cheapest and the slowest, uses transistor and capacitor, needs regualr refreshing [used in main system memory]
  • SRAM (Static RAM)- faster but more expensive than DRAM, does not use capacitor [built in CPU]
  • EDO (Extended Data-Out) RAM- allows more than one memory location to be accessed at the same time, speeds up data access [Main system memory]
  • SDRAM (Synchronous DRAM)- most common RAM in desktop PCs [Main system memory]
  • RDRAM (Rambus DRAM)- uses a high speed data bus to access memory locations, needs a specially designed motherboard [Main system memory]
  • VRAM (Video RAM)- High speed RAM used to hold graphics data including 3D models and textures [3D accelerator graphics cards]
  • Flash RAM

ROM (Read Only Memory)- memory whose content can be accessed and read but cannot be altered. Used for BIOS (on the ROM chip)- helps load the system

Varieties of ROM:

  • ROM- Permanent data storage [can be found in singing birthday candles and musical greeting cards]
  • PROM (Programmable ROM) - Permanent data storage. Data is added on to the blank ROM chips by a 'burning in' process. Easily damaged by static electric charges [used in security systems that need to prevent any alteration of data e.e. smart ID cards]
  • EPROM (Erasable Programmable ROM)- Data can be erased by exposing the chip to ultraviolet light. New data can then be added
  • EEPROM (Electronically Erasable Programmable ROM)- Data can easily altered without the need for special equipment or to remove the chip [used in cash registers, computer BIOS]
  • Flash memory

Magnetic Storage Devices

  • Common magnetic storage devices are tapes, hard disks and floppy disks.
  • Magnetic tape is still commonly used for storing backup data
  • Disks are organised into tracks and sectors that hold the data
  • Saving a file involves filling up a disk sector and recording the location of each sector used
  • Disk formatting prepares the surface to receive data

Optical storage devices

  • The term 'disc' is commonly used for optical storage devicws while 'disk' is used for magnetic devices
  • 'CD' stands for Compact Disc
  • CD-R technology uses a coloured dye that can be changed by heating to permanently record data
  • CD-RW technology uses a dye that can be swtiched between cloudy and transparent
  • DVDs (Digital Versatile Discs) can store data on two separate laters on both surfaces of the disc

Assess optical storage as a possible replacement for magnetic storage devices.
Optical storage devices can store a large quantity of data and cost very little to manufacture. If low portable storage is needed, then CD-Rws are probably better value than floppy disks. However, the do not match a hard disk for speed and storage capacity. If high capacity, high speed storage is needed, then hard disks are still a better choice than optical storage devices.

Questions
1. What is the most common type of RAM used in computers?
SDRAM (Synchronous Dynamic RAM)


  • uses bursts of higher speed to read the individual data bits once it has located the memory address
2. What makes EEPROM the most useful of the ROM type of memories?
The data on EEPROM can be easily altered without the need for special equipment or to remove the chip. It provides a convenient way to allow permanently stored instructions to be upgraded.

3. Optical storage devices store data as light- true or false?
False.

4. Why would PROM be an ideal storage device for security data?
Security data would usually require prevention of any alteration to the data. Having blank chips where security data can be added to and not altered makes PROM an ideal storage device for this type of data.

5. Give examples of situations where CD-R is a better choice for data storage than CD-RW


  • When handing in a final assignment to a teacher, having data that cannot be altered by anyone on the disc
  • When storing textbook information on a disc

6. 3.5 inch floppy disks have changed very little since they were first introduced in the mid 1980s- that makes them old technology. Give some reasons for their continued popularity.

  • compact
  • light
  • portable
  • removable data

7. Assess the advantages and disadvantages of flash storage devices as replacements for floppy disks.

Advantages

  • has a higher storage capacity
  • fast and does not require any power to keep data in storage
  • portable (small size)

Disadvantages

  • requires a small electric current to 'remember' its stored data

SSD- Solid State Drives: Instead of using a hard disk drive, it uses flash memory; permanently located inside the computer, secondary storage. Advs: fast, no moving parts to crash,

Sunday, August 22, 2010

Manipulating Video and Audio Data



Project File: A file created by Xcode that organizes source code, resources and settings used to build a product
  • Is saved with a .wlmp file name extension
  • Contains information about the arrangement and timing of photos, videos, text, muic, transitions, and effects that are used in the current project and appear on the storyboard. The original video, photo, and music files are linked to the project and aren't changed when editing in Movie Maker
  • Can be opened and edited in Movie Maker from where it was last saved
  • You can only open and view projects in Windows Live Movie Maker

Digital- A method of storing, processing and transmitting information through the use of distinct electronic or optical pulses that represent the binary digits 0 and 1.

Advantages and Disadvantages of digital data

Advantages
  • The system does not have noise (random unwanted variation)
  • Digital data doesn't degrade
  • Less expensive
  • More reliable
  • Easy to manipulate
  • Flexible
  • Compatible with other digital systems

Disadvantages

  • Sampling error
  • Require greater bandwith than analogue to transmit the same information
  • The detection of digital signals requires the communications system to be sycnhronised



Monday, May 10, 2010

Surveys and Interviews

Survey: a series of predetermined questions given to users of or participants in a system.

Purpose/ Advantage:
  • When responses are multiple choice or ranked numerically on strength of feeling the results can be collated in a database or spreadsheet and the trends observed.
  • Open questions provide an opportunity for users to respond freely and can reveal unanticipated needs.
Anonymous/Identifiable:
  • Responders to a survey can be anonymous; anonymity could generate honest responses or conversely, dishonest or non-serious responses
Closed questions: a question with a suggested limited number of responses which should be selected by the responder

Advantages:
  • trends can be can observed
  • anonymity

Disadvantages:
  • does little to encourage the responder to open up
  • not many people volunteer to complete surveys, often some sort of incentives are given to encourage responders
Open question: questions that do not suggest an answer and requires the responder to provide the answer

Advantages:
  • answers are of the responder's personal opinion and is not limited
Disadvantages:
  • trends cannot be easily observed
  • accurate analysis cannot easily be made to find a relation between numerous surveys

Interview: discuss formally with (somebody) for the purpose of evaluation

Purpose/Advantage:
  • open questions are normally employed, therefore they can probe more deeply than a survey
  • may suggest surprising new directions
Focus groups: a group activity where you gather users or participants with similar interests in the system; brings together a no. of people for a group discussion or interview were all can contribute their ideas.

Monday, May 3, 2010

Understanding the problem

Closed questions: have a fixed number of answers
Ex. Which of the following is your favourite colour?

Open questions: does not require a tick box or anything of the sort.
Ex. 'What did you do today?'

Interview: more in depth, unexpected resp0nses,

Survey: time-efficient, requires enticement, can it be analysed?
A good survey has a combination of closed and open questions, mostly closed perhaps ONE open question where you can invite an uninvited response

Survey: URL, McAuley students fill
McAuley network information system is accessed using a computer or laptop
In the near future, students will be able to carry these laptops around with them

Q. Issuing laptops to students
(be unbiased; give staff the survey; hand survey out to different focus groups; make a list for focus group to choose eg. 1. Parents 2.Staff 3.Students)

Q. Bringing your own laptop
Stakeholders: students, staff, parents

Issues: laptop being stolen, lost, virus
Rate this issue according to its importance

Sunday, May 2, 2010

System Development Cycle

Problems and Plans p.244

System Development Cycle (UMDIT)

  1. Understand the problem- Interview participants, survery participants, what are the inputs? what are the outputs? what are the processes? who is involved with the system?
  2. Making a decision- what type of solution? an IT solution? online or web-based?
  3. Designing a solution- (making it happen), decide what software and hardware are required e.g. make a spreadsheet and put it up on sharepoint for a bus duty roster
  4. Implementing the solution- preliminary testing. putting it on sharepoint, e-mailing everyone a set of instructions, installing hardware and software, training
  5. Testing & Evaluating-Maintaining a solution- experiment (get someone to try it out), getting feedback, sample data (data that represents the day-to-day; typical data) and test data (checking for pan unusual or unexpected value)

Using Excel

  • Formula; b7+c7+d7
  • Function; =SUM (b7:d7)

Sunday, March 14, 2010

Text book work- Systems Analyst & Ergonomics

p.309

A systems analyst researches problems, plans solutions, recommends software and systems, and coordinates development to meet business or other requirement. They work out what the needs of the users are and convey these needs to the designer of a system. (System analysts are the liaisons between vendors and IT professionals)

1. Name six ethical issues a systems analyst should consider.

  • giving an honest evaluation of user needs to IT professionals
  • ensuring that private information is not disclosed to unauthorised people
  • ensuring equity in the workplace
  • accuracy of analysis
  • awareness of the impact the information system may have on the participants
  • considering security of company information

2. Name four social issues a systems analyst must consider.

  • deciding whether the information system should be machine-centred or people-centred
  • ensuring an ergonomic work environment
  • considering the psychological factors of the information system,
  • ensuring the new information system makes participants' work more efficient

3. State the characteristics of people-centred systems.

  • focus is on the problem, not the tool
  • are easily understood
  • provide templates and assistants
  • work reliably
  • are user-friendly and intuitive
  • are placed in a suitable environment
  • are safe
  • are ergonomically sound
  • take advantage of the users' skills
  • look appealing
  • are efficient
  • reliever users of repetitive and boring tasks
  • enhance relationships and interaction with fellow workers
  • provide equitable access for all

eg. mobile phone, ATM machine, Google search engine, Laptops , Windows 7

4. In what ways are people like machines and in what ways are they different?

Similarities

  • are required to get work done
  • can understand the big picture as well as the detail
  • handle data

Differences

  • machines never get tired
  • machines do not forget
  • machines required programmed instructions to operate consistently
  • machines not do act intuitively
  • machines are incapable to think about the nature of work
  • machines do not create new any new ideas or associations
  • machines do not require training and retraining (need programming once only)
  • machines cannot recognise nonsensical output

5. List the major advances in the desktop computer since the earliest models.

  • Less bulky
  • Require less space
  • Flat VUDs
  • comfortable keyboard
  • aesthetically pleasing
  • compact, wireless mouse and keyboards are available
  • from CRT 15" monitors - LCD 22" monitors
  • Use of DVDs, CDs and USB instead of floppy disks
  • USB ports in front of PC, and not behind
  • Use of broadband instead of dial-up connections
  • Speeds have increased exponentially since then
  • RAM on a machine today is 4GB (4 000 000 KB) in contrast to 32 KB or 1MB
    RAM- everything that a computer is working on at one time
  • Multiple programs can run simultaneously (multitasking)

6. What do you predict the home computer system will be like in a decade's time?

- touch screen
-retina scan log-in
-voice operated

7. Identify the major social impacts that IT has had on our society in the past 20 years.

  • machines have replaced people in workplaces
  • machines make people's work less tedious and more efficient
  • with the introduction of IT, there is also the issue of ergonomics and health and safety
  • convenient
  • communication between children (Digital natives)
  • ways of storing photos, files has changed

8. Research details on RSI, both carpal tunnel syndrome and tenosynovitis (management on its causes, treatment and system design features that would reduce its impact on operators)

Repetitive strain injury (RSI) is an injury of the musculoskeletal and nervous systems that may be caused by repetitive tasks, forceful exertions, vibrations, mechanical compression (pressing against hard surfaces), or sustained or awkward positions. Treatment: ergonomics, break timers, keyboard alternatives and exercise.

Carpal tunnel syndrome is a painful disorder of the hand caused by pressure on the main nerve that runs through the wrist. Symptoms include numbness, pins and needles, and pain (particularly at night). Anything that causes swelling inside the wrist can cause carpal tunnel syndrome, including repetitive hand movements, pregnancy and arthritis. Treatment options include rest, splinting, cortisone injections and surgery.

Tenosynovitis is the inflammation of the fluid-filled sheath (called the synovium) that surrounds a tendon. Symptoms of tenosynovitis include pain, swelling and difficulty moving the particular joint where the inflammation occurs. Causes of tenosynovitis are unknown. Repeated use of hand tools can precede the condition, as well as arthritis or injury. Tenosynovitis sometimes runs in families and is generally seen more often in males than in females. Treatments for tenosynovitis depend on the severity of the inflammation and location. Mild tenosynovitis causing small scale swelling can be treated with non-steroidal anti-inflammatory drugs (NSAID) such as diclofenac (marketed as Voltaren and other trade names), taken to reduce inflammation and as an analgesic.

Treatments for tenosynovitis depend on the severity of the inflammation and location. Mild tenosynovitis causing small scale swelling can be treated with non-steroidal anti-inflammatory drugs (NSAID) such as diclofenac (marketed as Voltaren and other trade names), taken to reduce inflammation and as an analgesic.

Thursday, March 11, 2010

Machine centred & People centred

http://www.bettscomputers.com/

pages 303-309

People centred systems are designed so that the system fits the users' needs.
[tries to work out what your needs are, and meet your needs]

eg. Google search engine - allows for error and suggests the right input
ATM machine- bank comes to you, friendly user interface (least inconvenience)

Machine-centred system requires the user to serve the needs of the sytem.
-data might have to be in a particular format
-words would have to be spelt correctly
-formatting data and time it has to be entered
-prove identification; retina scan, thumb scanner
-particular location (eg. bank)
[performs a service for you, but may put you at an inconvenience]
eg.Graphics Calculator




Ergonomics is the science of designing the job, equipment and workplace to meet the needs of the worker.




Tuesday, March 9, 2010

Information Privacy Principles (IPPs)

Privacy Act 1988 regulates 'information privacy'

Information Privacy Principles

The IPPs regulate how Australian and ACT government agencies manage personal information.
They cover how and when personal information can be collected, how it should br used and disclosed, and storage and security. They also allow individuals to acess that information and have it corrected if it is wrong.

IPP 1: manner and purpose of collection
The information must be necessary for the agency's work, and collected fairly and lawfully.

IPP 2: collecting information directly from invididuals
An agency must tell individuals why they are collecting personal information, what laws give them authority to collect it, and to whom they usually disclose it.

IPP 3: collecting information generally
An agency must ensure the personal information it collects is relevant, up-to-date and complete and not collected in an unreasonably intrusive way.

IPP 4: storage and security
Personal information must be stored securely to prevent its loss or misuse.

IPP 5-7: access and amendment
These principles require agencies to take steps to record the type of personal information that they hold and give individuals access to personal info about them. Personal info can be amended or corrected if it is wrong.

IPP 8-10: information use
These principles outline the rules about keeping accurate, complete and up-to-date personal information; using info for a relevant purpose; and only using the info for another purpose in special circumstances, such as with the individual's consent or for some health and safety or law enforcement reasons.

IPP 11: disclosure
This principle sets out when an agency may disclose personal info to someone else, for ex. another agency. This can only be done in special circumstances, such as with the individual's consent or for some health and safety or law enforcement reasons.

Monday, March 8, 2010

Social & Ethical Issues; Presentations

FACEBOOK


Privacy
  • you can choose in your account settings who can see what

  • some applications require you to to 'Allow' your information to be leaked into foreign systems

  • instructs users how to change new privacy settings; update all settings

Security

  • Only you can alter the information on you profile and your settings

Data Quality

  • Companies have facebook sites, which can used a way of getting feedback from users and advertise products

Health & Safety

  • Cyber bullying
  • Peer Pressure

Copyright Laws

  • refer to the copying of images, videos and music
  • facebook policy on intellectual property; breaches of copyright can be reported to facebook

YOUTUBE

Privacy

  • If it's on youtube anyone can see it; more than likely it is exposed to the whole world
  • You can hide certain personal information

Security of data and info

  • People could pretend to be you and upload videos that breach the terms of Youtube, thereby putting the blame on you for THEIR wrongdoing

Accuracy of data and info

  • It is not an open system, you can decide what content is judged as inappropriate and it can be removed
  • breaching copyright

Changing nature of work

  • People become recognised because of hits on videos uploaded on youtube; youtube allows for promotion
  • Bypassing the process of connections and meeting people to become famous, by straight away facing the audience via youtube

Copyright Laws

  • Videos that don't show any copyright authority are removed immediately
  • Copyright organisations are involved in monitoring videos

Thursday, February 25, 2010

Ethical Issues- Google Executives & Facebook defaced

If an organisation of info. system is hosting information, are they responsible for the content?

Google Executives jailed in Italy

In Italy, three Google executives have been found guilty and given six month suspended sentences because of a video that shows the mistreatment of a boy with Down Syndrome.

[Reasons and arguments why prosecutors thought google was liable]

Prosecutors argued that Google execs were negligent; not responding to requests to take down the video
Google hosts YouTube, therefore there is a question to are they responsible for the content/

Google's defence- that the execs had nothing to do with the video and that it is almost imopossible to review every single frame in a video to permit it to be uploaded online

Facebook urged to act after memorial sites defaced

Premier of QLD, Anna Bligh, has written a letter to Facebook to review memorial pages on its site after a case of a young girl's memorial page being defaced by certain people.

Tuesday, February 23, 2010

Tools for transmitting and receiving

Binary digits- 0s and 1s



Serial data transmission- a form of data transmission in which the bits of each character are sent one at a time along a single communication path [one path] eg. mouse, USB- Universal Serial Bus, Internet



Parallel transmission data- a form of data transmission in which the bits of each character are all sent simultaneously, resulting in extrememly fast communication but requiring a communication path for each bit.


[8 paths] eg. some printers with parallel port
  • faster, but over longer distances the data goes out of sync and takes a longer time to arrive, therefore serial is preferred over longer distances


Signal Direction



Simplex- data links that allow the data to move in one direction. In a simplex link there is no need for a return data signal [one way communication] eg. radio, traditional free-to-air television



Half Duplex- data links that allow the data to move in both directions, but not at the same time [one way at a time] eg. UHF radio



Full Duplex- (also known as duplex) data links allow the data to move simultaneously in both directions. [Both devices in the link must be able to send and receive at the same time] eg. mobile phones, landline telephones

Synchronous- communication links use agreed times for data to be transmitted and received [happen at the same time- real time] eg. phone calls, skype, text chat, dedicated video conference

Asynchronous- no set time for the data to be transmitted or received [out of time-delayed] eg. text message, e-mails, blogs, forums, podcasts, videoblogs


Useful links: http://learningwithcomputers.pnworks.com/Synchronous-Communication
Google 'examples of synchronous communications csu hsc edu' and open powerpoint

Data Signals

Bandwith- the number of bits moving at any given time

Baud- transmission cycle; every transmission occurs in a cycle or transmissions per cycle; how times per second data(bits) is transmitted

Saturday, February 20, 2010

Diagrams of an information systems


A context diagram of an information system shows the situation or environment where it is used, the sources of its inputs and the destinations of its outputs.


A data flow diagram (DFD) shows how data move through an information system; movement of data.
4 components


Example 1



Example 2





Mastery Test Ch.1

Multiple Choice

1. A system is (c) a collection of parts that work together

2. An information system system (a) turns data into information

3. A person who attributes data to an info. system but is not involved in its operation and does not use any info. or data it produces is (c) in the system environment

4. The environment of an information systems (d) describes where it used

5. The info. technology of an information systems is (b) its equipment and instructions

6. A personal info.system (c) is designed for use by individuals

7. Which part of an info. systems will end users find most useful?
(a) data and information

8. Which list contains all the categories that would be needed to adequately describe the role of an info. system?
(c) data/information, purpose. info. processes

9. The participants [eg.web designers, software engineers, data entry operators] in an information system (a) are responsible for its operation

10. A home PC is an example of (d) a generalized info. system

Fill in the blanks

11. A system is a collection of parts that work together to achieve a particular purpose or result

12. All systems have inputs, processes and outputs [IPO diagrams]

13. An information system accepts data as an input and produces information or processed data as an output

14. Every system has a purpose that describes why it is needed and an environment where it is used

15. Information technology is the equipment (hardware) used by an info system and the instructions (software) that control the equipment

16. A participant is anyone who is involved in the operation or running of an info system

17. Info. systems depend on their environment for data

18. An end user is the person who receives the info. produced by an info system

19. The environment is where an info system is used by many different participants

20. A group information systems is used by many different participants
Match the terms

1. G
2. D

3. A

4. F

5. C

6. J

7. A

8. B

9. E

10. H

22. Identify the info technology and participants in a computerised library catalogue/ circulation info system.
-
Computer, barcode scanner, books, barcodes, data-entry operator, librarian

23. Explain how new developments in technology have influenced info. systems
-
Has caused higher expecation ad greater needs by many individuals
[eg. iPod- music can be accessed anywhere and downloaded at any place provided there is Wi Fi
Netbooks - quick and easy access to internet
Web 2.0- placing applications online, only need of browser to access applications, not necessarily online]

24. Describe how computer-based IT has altered the roles of participants in info. systems
-
eliminated tedious tasks
- machines replace humans
- end users become data-entry operators

25. Justify that computer-based info. systems have become a vital point of our lifestyles
-
used for various tasks inclding online banking, online shopping, means of communcation and research etc.

26. Contrast the roles of end users in personal and group info. systems
-
full control over limited control
- not shared over shared information

Sunday, February 14, 2010

Social and Ethical Issues

Privacy and security- data can be shared quickly between large no. of different information systems. At each system any no. of users may have access to the data. This puts private and confidential information at risk of being misusesd and abused. Data must be protected against accidental or deliberate damage.

Access and control- without communication systems, such as the Internet and telephone network, there would be little or no flow of info. to users. Controllers of systems, control the information. Linked with equity; for eg. students in regional area who do not have broadband access may be disadvantaged in terms of preparing for HSC OR pensioners who have to pay bills online because a surplus fee is added for

Employment and the changing nature of work- those with lack of information skills and cannot use new technology become at risk of unemployment. In an effort to compete in the global market, industries may be forced to downsize their workers and automate their manufacturing operations. Even workers in high-technology jobs will have to constantly retrain to keep their skills and jobs.
-Telecommuting- working at home; miss out on social interaction, more distractions, like looking after children

Data Type; Text











Sunday, February 7, 2010

Data and Information

1. For each of the scenarios in the table below, locate an informtion system and then complete the table;


Information System in context