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Introduction to Computer Technology An introduction to
databases, spreadsheets and word processing. Practical competences
The candidate must be able to do the following: Load, save and
print 200.129 Select a suitable software application for a given
task. Software:word processing, database, spreadsheet 200.130 Load
applications software. 200.131 Load a data file. 200.132 Save a
data file with an appropriate filename. 200.133 Print out all or
part of a data file. 200.134 Exit application software to return to
the operating system or graphical user interface (GUI). Word
processing 200.136 Open a new file and enter text.
200.137 Edit the contents of a document. - change or corrects
some words Edit: correct errors, insert word(s), delete word(s),
insert paragraph breaks, delete paragraph breaks 200.138 Improve
the appearance of a document. Improve the appearance: bold,
centre
Editing a database 200.139 Edit data into an existing database
file. Edit: add, delete, amend data 200.140 Define and execute a
single condition search using appropriate operators. Numerical
operators: less than (), equal to (=)
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200.141 Sort a data file into numerical or alphabetical order.
Editing a spreadsheet
200.142 Identify and move the cell pointer to any row, column
and cell within a spreadsheet using cursor keys or mouse control.
Cursor keys: up, down, left, right Mouse control: point and click,
use of scroll bars 200.143 Edit the contents of a cell in an
existing spreadsheet file. Edit: amend, replace, delete 200.144
Insert and delete columns and rows in a spreadsheet. 200.145 Insert
formulae, containing cell addresses and numbers, to add, subtract,
multiply and divide. 200.146 Use the sum function in spreadsheets
to sum rows and columns.
= sum(H3:I3) 200.147 Replicate a formulae in a row or a
column.
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Knowledge requirements Instructors must ensure that candidates
are able to: Hardware and software
200.148 Identify the four main components of a computer system.
Main components: main processor, input, output, storage A Computer
is actually a programmable, multi-use machine that accepts data-raw
facts and figures, and processes, or manipulates them into useful
information. It is constructed from 4 main components namely:
Hardware all the physical parts that we can touch that makes up
a system (in human: body, bones, heart liver, fingers, blood; in
Computers: Screen, Chips, Electronic parts, mouse, keyboard,
CPU,
Software - is all the intangible part that drives the physical
parts to operate
Operating system - is the software that is needed to give life
to all the system parts and must be added first to the hardware (in
humans: life or soul; in computers Windows, Linux, Android, etc.)
Some basic applications (utilities) come built in the operating
system
Application software - is the software that is added to a live
and working system to give it specific abilities (in humans: wisdom
knowledge, skills; in computers Spread Sheet (like Excel), Word
Processor (like MS word)
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COMPUTER STORAGE SYSTEMS
200.149 Describe the components of a microcomputer system.
Components: keyboard, mouse, CPU, monitor (VDU), disk drive,
printer
CENTRAL PROCESSING UNIT (Processor + Main board circuitry)
Secondary storage Hard Disk CD ROM DVD USB Memory
PRIMARY STORAGE SECONDARY STORAGE
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200.150 Explain that software is a set of instructions that
enables the computer to carry out operations. Software is the
general term used to describe programs, which are used on a
computer and consists of the step by step instructions that tell
the computer how to perform a task or operations. It has to be
written by a programmer. Main classes of software are shown
below:
200.151 Identify the main functions of commonly used software
applications packages. Packages/functions: spreadsheet (numerical
analysis and manipulation), word processing (document production),
database (file creation, updating, searching and sorting), computer
aided design (line drawings used for architecture and engineering)
Operating System An operating system (OS) is a set of programs that
manages all computer resources including hardware and providing
common services to other software application programs. The
operating system is the most important type of system software in a
computer system. Without an operating system, a user cannot run an
application program on their computer. Eg: Windows vista &
Windows 7, Windows XP, DOS, CP/M, UNIX, Mac OS, LINUX, Solaris,
Windows 95, 98, ME, Windows 2000, Windows CE, and Server versions
(Windows NT, Windows server 2008 R2) are some examples of operating
system software Spreadsheet (numerical analysis and manipulation),
A spreadsheet is designed to aid in doing bookkeeping, accounting,
and modeling of business problems. It can also be used in other
computational situations in which one works with a table of numbers
and formulas. A key feature is that the computer system can
automatically rework all of the computations represented in the
table whenever changes are made to any of the numbers or formulas.
Example is MS excel Graphing (for graphing data and functions)
Numerical data is easily converted to a wide range of different
types of graphs, such as bar graph, line graph, pie chart, and so
on. Mathematical functions can be represented graphically. For
example, a three-dimensional mathematical surface can be
represented on the computer screen and then rotated to allow
viewing from different perspectives. These functions are usually
included in the spreadsheet these days. Word processing (document
production), A word processor is software designed to aid in
writing documents. A modern word processor contains a number of
features, such as a spell checker, thesaurus, graphics, and
graphing, that may be of use to a writer. Example is MS word
Database (file creation, updating, searching and sorting), A
database keeps records in tables that are organized and hidden
inside it, but are easily searchable and retrievable through simple
and friendly user interfaces like forms and queries. A database is
a software that was designed to replace manual filing e.g. employee
records, bank details records, school pupils records etc. A
telephone book is a database of names, addresses, and telephone
numbers. A computerized database is much easier to edit (add
entries, make corrections, delete entries) than a printed database.
A computerized database is designed to make it easy to locate
needed information. It is also designed to make it easy to sort
information into a desired format or to prepare reports based on
parts of the
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information. For example, a customer database could be used to
produce a report on all customers located in Harare or Bulawayo or
Mutare only who spent more than $100 during the past three months.
Exam[ple is MS Access Computer aided design (line drawings used for
architecture and engineering) CAD software is used to do
architectural and engineering drawings of products that are to be
constructed. A CAD system can be used in the design of all sorts of
products. Such software is used in place of the ruler, compass,
protractor, and other tools formerly used by the draftsperson. An
example of CAD Software is AutoCAD Desktop presentation (to
accompany oral presentations). The overhead projector, filmstrip
projector, movie projector, [slide projector], tape recorder, and
video projector have gradually merged into a computer-based system.
Material to be presented is stored on computer disk in digital form
and edited using the computer. The presenter then uses the
desktop-presentation system interactively when making the oral
presentation. Example is MS PowerPoint. Desktop publication A
computer system is used to store, edit, design, and lay out the
materials that are to be published in printed form. Output may be
to a printer, to film used to make plates to go on a printing
press, or directly to a printing press. Example is MS publisher
Graphics (paint and draw programs). A paint program has some of the
characteristics of a set of painting tools, while a draw program
has some of the characteristics of a set of drawing tools. Taken
together, these tools can be used to accomplish a wide range of
graphic artist tasks. Moreover, photographs can be digitized and
then edited using computer graphics capabilities. Similarly,
individual frames of video material can be edited using computer
graphics facilities. The graphics that are produced can be used in
a word-processing document, in desktop presentation, or in other
types of computer applications. Example is Coral draw and Adobe
Photoshop Data input and output 200.152 Describe different methods
for inputting data and their applications. Methods: direct entry
(keyboard), OCR, OMR, scanner, bar code reader, electronic file,
remote data logger, electronic sensor (transducer)
Keyboard Keyboard allows users to key in data using alphanumeric
characters pads on it. The computer converts the key board signals
into binary format (data bits) that it then stores in memory
Optical Character Recognition (OCR) (OCR) is a software
technology that can convert images of text into an actual text file
that can then be edited, e.g. using word-processing software). The
result is just as if the text had been typed in by hand. OCR is
typically used after a page of a book has been scanned. The scanned
image of the page is then analyzed by the OCR software which looks
for recognizable letter shapes and generates a matching text file.
Advanced OCR software can recognize normal handwriting as well as
printed text - this is usually called handwriting recognition.
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Optical Mark Recognition (OMR) OMR is a technology that allows
the data from a multiple-choice type form to be read quickly and
accurately into a computer. Special OMR forms are used which have
spaces that can be colored in (usually using a pencil). These marks
can then be detected by an OMR scanner. Common uses of OMR are
multiple-choice exam answer sheets and lottery number forms.
Magnetic Ink Character Recognition (MICR) is a technology that
allows details from bank cheques to be read into a computer quickly
and accurately. The cheque number and bank account number are
printed at the bottom of each bank cheque in special magnetic ink
using a special font. These numbers can be detected by an MICR
reader.
Scanner In computing, an image scanneroften abbreviated to just
scanneris a device that optically scans images, printed text,
handwriting, or an object, and converts it to a digital image.
Common examples found in offices are variations of the desktop (or
flatbed) scanner where the document is placed on a glass window for
scanning. Hand-held scanners, where the device is moved by hand,
have evolved from text scanning "wands" to 3D scanners used for
industrial design, reverse engineering, test and measurement,
orthotics, gaming and other applications. Mechanically driven
scanners that move the document are typically used for large-format
documents, where a flatbed design would be impractical.
Bar code reader A barcode is simply a numeric code represented
as a series of lines. These lines can be read by a barcode
reader/scanner. The most common use of barcode readers is at
Point-of-Sale (POS) in a shop. The code for each item to be
purchased needs to be entered into the computer. Reading the
barcode is far quicker and more accurate than typing in each code
using a keypad. Barcode can be found on many other items that have
numeric codes which have to be read quickly and accurately - for
example ID cards. Corresponding details /records are stored in the
computer database.
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Electronic file, An electronic document is any electronic media
contents (other than computer programs or system files) that are
intended to be used in either an electronic form or as printed
output. Originally, any computer data were considered as something
internal the final data output was always on paper. However, the
development of computer networks has made it so that in most cases
it is much more convenient to distribute electronic documents than
printed ones. And the improvements in electronic display
technologies mean that in most cases it is possible to view
documents on screen instead of printing them (thus saving paper and
the space required to store the printed copies).
Remote data logger Data loggers are used in a variety of
industries and applications including remote water resource
monitoring, weather condition monitoring, machine monitoring, gas
and oil projects, building HVAC control, and structural vibration
monitoring in bridges and buildings. A data loggers primary purpose
is to automatically collect data points from sensors and make these
data points available for review, analysis, and decision making
processes. Many data loggers can also be programmed for other
purposes, such as alarm and control conditions. The
microprocessor-based data logger was a revolutionary data
acquisition tool that replaced most of the historical
mechanical-based paper chart and punch tape recorders, which
required either manual data input from the charts or scanned data
using special equipment that could create a digital file from the
paper record.
Electronic sensor (transducer) - here is the microphone that
converts a physical signal property into electrical form
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Analogue Sensors produce a continuous output signal or voltage
which is generally proportional to the quantity being measured.
Physical quantities such as Temperature, Speed, Pressure,
Displacement, Strain etc are all analogue quantities as they tend
to be continuous in nature
Digital Sensors produce a discrete output signal or voltage that
is a digital representation of the quantity being measured. Digital
sensors produce a Binary output signal in the form of a logic "1"
or a logic "0", ("ON" or "OFF"). This means then that a digital
signal only produces discrete (non-continuous) values which may be
outputted as a single "bit", (serial transmission) or by combining
the bits to produce a single "byte" output (parallel transmission).
ELECTRONIC SENSORs (TRANSDUCER) Transducer a device that converts a
primary form of energy into a corresponding signal with a different
energy form
signal with a different energy form Primary Energy Forms:
mechanical, thermal, electromagnetic, optical, chemical, etc. takes
the form of a sensor or actuator
Sensor (e.g., thermometer) a device that detects/measures a
signal or stimulus acquires information from the real world real
world
Actuator (e.g., heater) a device that generates a signal or
stimulus
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Quantity being Measured
Input Device (Sensor)
Output Device (Actuator)
Light Level Light Dependent Resistor (LDR), Photodiode,
Photo-transistor, Solar Cell
Lights & Lamps, LED's & Displays, Fibre Optics
Temperature Thermocouple, Thermistor, Thermostat Resistive
temperature detectors (RTD)
Heater, Fan
Force/Pressure Strain Gauge, Pressure Switch,Load Cells Lifts
& Jacks, Electromagnet, Vibration
Position Potentiometer, Encoders, Reflective/Slotted
Opto-switch, LVDT
Motor, Solenoid, Panel Meters
Speed Tacho-generator, Reflective/Slotted Opto-coupler, Doppler
Effect Sensors
AC and DC Motors, Stepper, Motor Brake
Sound Carbon Microphone,Piezo-electric Crystal Bell, Buzzer
Loudspeaker
200.153 Describe devices used to output data. Devices: screen,
printer, control devices, audio systems
Screen or Visual Display Unit (VDU) A monitor displays text and
image data passed to it by the computer. A cathode-ray tube (CRT)
monitor is the type that has been around for years and is large and
boxy. CRT monitors are heavy and they take up a lot of desk space.
They have largely been replaced by flat-screen monitors. However
some are still used in the design industry since the colour
accuracy and brightness of CRT monitors is excellent (high
resolution), and designers need to see true-to-life colours.CRT
monitors are generally cheaper than flat-screen monitors.
Flat-Screen Monitor (TFT or LCD) Over the past few years, as they
have come down in price, flat-screen displays have replaced CRT
monitors. Flat-screen monitors are light in weight and they take up
very little desk space. Modern flat-screen monitors have apicture
quality that is as good as CRT monitors. TFT and LCD are two of the
technologies used in flat-screen monitors: TFT is
Thin-Film-Transistor, and LCD is Liquid-Crystal Display. Another
technology that may replace these is OLED or Organic Light-Emitting
Diodes.
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Projector A video projector is an image projector that receives
a video signal and projects the corresponding image on a projection
screen using a lens system. All video projectors use a very bright
light to project the image, and most modern ones can correct any
curves, blurriness, and other inconsistencies through manual
settings. Video projectors are widely used for many applications
such as, conference room presentations, classroom training, home
theatre and concerts. Projectors are widely used in many schools
and other educational settings,[1] sometimes connected to an
interactive whiteboard to interactively teach pupils.
printer A printer is a peripheral which produces a
representation of an electronic document on physical media such as
paper or transparency film. Many printers are local peripherals
connected directly to a nearby personal computer.
Control devices An actuator is a type of motor for moving or
controlling a mechanism or system. It is operated by a source of
energy, usually in the form of an electric current, hydraulic fluid
pressure or pneumatic pressure, and converts that energy into some
kind of motion. An actuator is the mechanism by which a control
system acts upon an environment. The control system can be simple
(a fixed mechanical or electronic system), software-based (e.g. a
printer driver, robot control system), or a human or other
agent.
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Audio systems They convert electrical signals into sound waves.
Loudspeakers are essential for applications such as music editing,
video conferencing, watching movies, etc.
200.154 Compare printers for output in terms of speed and cost.
Printers: ink-jet printer, laser printer, impact (dot matrix, daisy
wheel)
impact (dot matrix, daisy wheel) A dot-matrix printer is named
after the pattern (a grid or matrix) of dots used when creating the
paper printout. These dots are formed by tiny pins in the printers
print head that hit an inked ribbon against the paper leaving
marks. As the print head moves along it leaves a pattern of dots
behind it which can form letters, images, etc. Dot matrix printers
often use continuous stationary: long, continuous strips of paper
(rather than separate sheets of A4 like ink-jet and laser printers
use). After printing, the printout is torn off from the long strip.
Dot-matrix print quality is poor, the printers are noisy, and there
are much better printing systems available today. However, the
dot-matrix printers are still used in certain situations: Since the
pins actually hit the paper, several carbon-copies (duplicate) can
be printed in one go. An example of this is airline tickets which
have several duplicate pages, all printed in one go The print
mechanism is very cheap, and the inked ribbons last for a long
time. So, where cheap, low-quality printouts are required,
dot-matrix printers are used. An example is shop receipts.
ink-jet printer Cheap, high-quality, full-colour printing became
available during the 1980s due to the development of ink-jet
printers. These printers have a similar print-head mechanism to a
dot-matrix printer. The print-head passes left and right across the
paper. However, instead of using pins to hit inky marks onto the
paper, the ink-jet squirts(furidza) tiny droplets of ink onto the
surface of the paper. Several coloured inks can be used to produce
full-colour printouts. The droplets of ink come from tiny holes
(the jets) which are less than the width of a human hair in size.
Each droplet creates a tiny dot on the paper. Since the dots are so
small, the quality of the printout is excellent (1200 dots-per-inch
are possible). This is perfect for photographs. Ink-jet printers
are very quiet in use. Since they have so few moving parts they are
also reasonably cheap to manufacture and thus cheap to purchase.
However, the ink is very expensive to buy (this is how the printer
companies make their profits!) so the printers are expensive to
use. Ink cartridges are expensive, high maintenance cost.
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This is a close-up of the tiny ink dots on a page. The dots
combine to form light and dark areas.
laser printer Laser printers are very complex devices, and thus
most expensive to buy. However they are very cheap to use (low
maintenance cost). This is because they produce marks on paper
using a fine dust called toner which is relatively cheap to buy. A
single toner cartridge will often last for 5,000-10,000 pages of
printing. The laser printer uses a complex system, involving a
laser, to make the toner stick to the required parts of the paper.
(This system is very different to a dot-matrix or ink-jet, and you
dont need to know the details.) The laser and toner system allows
very fast printing compared to other printers (just a few seconds
per page). Laser printers are very common in offices since they
print very quickly, are cheap to use and are reasonably quiet.
200.155 Describe typical media for storing data and programs.
Media: floppy disk, hard disk, CD-ROM, tape streamers, cassettes
Backing storage (sometimes known as secondary storage) is the name
for all other data storage devices in a computer: hard-drive, CD
ROM, DVD, Tape, Floppy Disk, cassettes etc. Backing storage is
usually non-volatile, so it is generally used to store data for a
long time. Backing storage devices are slower to access, but can
hold data permanently... Data storage Magnetic storage media and
devices store data in the form of tiny magnetised dots. These dots
are created, read and erased using magnetic fields created by very
tiny electromagnets. In the case of magnetic tape the dots are
arranged along the length of along plastic strip which has been
coated with a magnetisable layer (audio and video tapes use a
similar technology). In the case of magnetic discs (e.g. floppy
disc or hard-drive), the dots are arranged in circles on the
surface of a plastic, metal or glass disc that has a magnetisable
coating.
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A hard-drive can save/read data at a speed of 300MBps (5000
times quicker than the floppy!) Hard-drives have a very large
storage capacity (up to 1TB). They can be used to store vast
amounts of data. Hard-drives are random access devices and can be
used to store all types of films, including huge files such as
movies. Data access speeds are very fast. Data is stored inside a
hard-
drive on rotating metal or glass discs (called platters). A
removable, portable, cheap, low-capacity (1.44MB) storage medium.
Floppy discs are random access devices used for transfer small
amounts of data between computers, or to back-up small files, etc.
Access times are slow. Almost every PC used to have a floppy disc
drive. These are obsolete now, having been replaced by higher
capacity technology such as CD-ROMs, DVDs and USB memory sticks.
They are vulnerable to damage from mishandling like: magnetic
fields, flexing or bending, excessive temperature, touching the
magnetic surface, removing the disk while in use, and excessive
amounts of dust or smoke.
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CD-ROM- Optical storage devices save data as patterns of dots
that can be read using light. A laser beam is the usual light
source. The data on the storage medium is read by bouncing the
laser beam off the surface of the medium. If the beam hits a dot it
is reflected back differently to how it would be if there
was no dot. This difference can be detected, so the data can be
read. Dots can be created using the laser beam (for media that is
writable such as CD-Rs). The beam is used in a high-power mode to
actually mark the surface of the medium, making a dot. This process
is known as burning data onto a disc.
Tape Streamers Many microcomputer users use a device called a
magnetic tape streamer or a backup tape cartridge unit to make a
backup of the data found on hard disk. Typical capacities of such
tape cartridges are 120 megabytes to 5 gigabytes. Advanced forms of
backup technology known as digital audiotape (dat) drives that use
2-inch by 3-inch cassettes store 4 gigabytes or more. Although the
data on a streamer tape exists in a similar format to that of
reel-to-reel tape, it does not allow for stopping between data
blocks and passes over the inter-gaps-blocks without passing. Long
data block of up to 16,000 characters (16 Kbytes) are used to
maintain a high rate of data transfer
Cassettes Magnetic tape is a large capacity, serial access
medium. Because it is a serial access medium, accessing individual
files on a tape is slow. Tapes are used where large amounts of data
need to be stored, but where quick access to individual files is
not required. A typical use is for data back-up (lots of data, but
rarely only accessed in an emergency) Tapes are also used and in
some batch-processing applications (e.g. to hold the list of data
that will be processed).
200.156 State that computer memory (RAM) is volatile and that
any data not stored will be lost. Main memory (sometimes known as
internal memory or primary storage) is another name for RAM (and
ROM). Main memory is usually used to store data temporarily. In the
case of RAM, it is volatile (this means that when power is switched
off all of the data in the memory disappears). Main memory is used
to store data whilst it is being processed by the CPU. Data can be
put into memory, and read back from it, very quickly. Memory is
fast to access, but only holds data temporarily...when power is on
only. 200.157 State why floppy disk must be formatted before use
and the effect on previously recorded data of formatting a disk.
Formatting is the process of writing marks on the magnetic media
that are used to mark tracks and sectors. Before a disk is
formatted, its magnetic surface is a random order. When it is
formatted, some order is brought into the magnetic field alignment
by essentially drawing lines where the tracks go, and where they
are divided into sectors.
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Health and Safety It is recommended that candidates undertake a
basic first aid course and have various types of fire extinguisher
demonstrated to them. Practical competences The candidate must be
able to do the following: Practical safety in the workplace 200.158
Identify hazards and safety facilities in a workshop. Knowledge
requirements Instructors must ensure that candidates are able to:
Safety in the workplace 200.159 Describe the general requirements
for the observance of safe practice. General requirements:
alertness to danger, maintaining personal hygiene, general
tidiness, protecting self and others, a knowledge of emergency and
hazard reporting procedures 200.160 Describe the human and
environmental factors that may lead to an accident. Factors:
tiredness, carelessness, improper behaviour, lack of training,
unguarded or faulty tools and machinery, unsuitable clothing, lack
of adequate ventilation 200.161 Explain the dangers associated with
the following materials. Materials: compressed gases, cryogenic
materials, noxious fumes and liquids, explosives, combustible
materials, salt baths 200.162 State the need for eye protection in
relation to sparks, dust, chippings, liquid splashes. 200.163 State
special precautions to be observed when working with hazardous
substances. Hazardous substances: industrial chemicals, poisons,
toxic gases, petro-chemicals 200.164 State the types of fire
extinguisher generally available in an industrial environment and
their suitability for different types of fire. Fire
extinguisher:water, foam, dry powder, carbon dioxide Types of fire:
dry materials, oil and petrol, electrical 200.165 Describe the
first aid procedures required in the event of an industrial
accident. First aid procedures: dealing with electric shock,
administering mouth to mouth resuscitation, dealing with eye and
other types of physical injury 200.166 Describe the sources of
electrical danger and the methods of protection. Methods of
protection: insulation, earthing, circuit breakers, fuses, residual
current devices (RCD) 200.167 State the essential procedures for
the safe handling and storage of materials. 200.168 State the
correct procedures for lifting bulky or heavy loads including
manual lifting and the safe use of lifting equipment. 18 IVQ