Unit 3 & 4 IP&M
With special acknowledgement of Mark Kelly and the McKinnon site
"I'm In IPM and I Don't Know
Anything About What's Inside
Ahhhhhhhh theory again!
Talking about the insides of
What's a bus doing in a
computer? If that kid there
mentions floppies again, I'm
going to complain to the
Selection one of the following ,,,,,,,,,,,,,,,,,,,,,,,,,,10 points for each correct answer………….
Information systems are made up of
is any part of a
computer system that you can
touch, pick up, drop, or kick.
What is a mouse?
the pointing device invented to make GUI
(Graphical User Interfaces) possible.
The mouse ball drives two rollers, one rolling horizontally, the other
vertically. The speed, direction and distance of mouse moves along
with any clicks on the buttons is sent to the operating system for
interpretation and action. Typical mice (mouses?) with balls suffer
from getting gunk on the rollers and must be cleaned occasionally
for smooth operation. Some more recent mice do away with the
mouse ball and use tiny lasers to read movement under the mouse.
What is a pixel?
Each "dot" on a screen is called a "pixel" (shortened
from "picture element".) Each pixel is made up of
three coloured dots (one red, one green, one blue).
This is where the "RGB" (red/green/blue) stuff come
into discussions of video display. By varying the
strength of the glow of each coloured dot, a pixel can
show an enormous range of colours.
but it must be stored on
hardware (disks, memory chips, tape
What is a hard disk?
A hard disk, also called a hard disk drive, consists of several
inflexible, circular platters that store items electronically.
A magnetic disk stores the 'on' and 'off' bits of binary data as
microscopic magnetized needles on the surface of the disk. This
data can be recorded and erased any number of times. When
computer power is turned off, the data remains stored on the
(cont’d next slide)
: seriously primitive but amazingly reliable and accurate. Using one is like
tossing a coin and hoping you get a million heads in a row
but it works! Imagine an
aluminium disk about 3.5" (9 cm) in diameter and 2mm thick. Imagine it is on a
spindle with maybe 10 or 20 similar disks on the same spindle spinning at 7,200
revolutions per minute (a racing motor bike would be screaming to change gear at
Imagine each disk had a tiny read/write head on a metal stick hovering above its
upper and lower surfaces
how high is the head hovering? Considerably lower than
the height of human hair or a speck of grease left by a finger print. The only thing
keeping the head off the surface of the disk is the few atoms of air holding the head
up. Imagine this flying head trying to magnetise a part of the disk, or read the
magnetic information already stored on the disk. It has to pack a few million ones and
zeros into a few millimetres of disk. It has to do it with 100% accuracy. It's like trying
to drop a tennis ball into a bucket from a jet fighter doing 1000 km/h at 10,000 feet.
Then you have to circle the fighter and pluck the ball from the bucket 600 times
making a mistake.
Yet, that's what we expect our hard disks to do every day and swear like sailors when
they fail. Personally, I would give hard disk makers medals for magic. The whole
concept is mind
boggling, but it's happening even as you read this.
Your average hard disk today stores between 10 and 40 GIGABYTES
million ones and zeroes. How would you like writing the complete works of
Shakespeare a million times on a credit card? More than that, you'd have to read it
back perfectly every time you were asked. Amazingly amazing.
Most of the time I prefer not to think about how amazing it is that my hard disk works
as well as it does. Most of you probably didn't even need to know it was important
that you shouldn't think about it. What
important is to back up your data so when
the magic of the hard disk inevitably stumbles, you are not surprised. It
some time, it
to. You just need to be prepared when it does: and give
thanks that it lasted as long as it did.
What is the motherboard?
This is the main circuit board of the PC. It contains all the basic, core
components of the computer. It usually contains:
(Basic Input Output System)
Real time Clock (RTC)
so the computer knows the time and date.
to control basic devices such as hard disks, floppy disks,
serial/parallel ports etc.
What is a joystick?
are game devices to input
movement data. They are easier to use than
mice for games such as flight simulators and
racing simulators. Yes, they are named after
the controls in planes.
What is RAM?
RAM (Random Access Memory)
: Chips that store
data and programs. RAM loses its memory when power
is turned off, which means you will need to save your
data and information to a permanent medium (like hard
the power goes off. RAM is rated by its
density and speed of retrieval.
What does (monitor) resolution mean?
The amount of detail a monitor can show is
. The standard minimum
resulution nowadays is 800 by 600 pixels.
Many people use higher resolution (e.g. 1024 x
What is a trackball?
are like upside down mice: the big
ball is rolled with the palm of the hand and the
fingers. Since trackballs sit still on the desk,
they are handy if space is limited, and the big
ball makes precise mouse movement a bit
What is a graphics tablet?
have a surface like a large
touchpad with a pen (stylus) attached. You use the
stylus on the tablet to move the mouse pointer.
Graphics tablets are commonly used in graphics,
art, handwriting input and data plotting. For
freehand drawing, a graphics tablet's pen can be
much easier to use than a mouse.
What is ROM?
Only Memory (and PROM, EPROM,
EEPROM, Flash RAM) are different to RAM mainly
because they can keep their memory after the power
goes off. Once ROM has had its data burned into it,
it can never be changed
What is the function of
Central Processor Unit. The heart of a personal
computer (PC). It is the central brain of the whole computer
system. In the old days, the CPU was the only processor in a
PC. It did
and it showed.
Nowadays, most 'peripheral' devices have their own
processors, and the CPU acts like an office General
Manager who delegates work. Rather than trying to do
everything, the CPU often sends commands to other
What is a USB memory key?
USB memory keys (or sometimes called memory
sticks) are small devices that plug into a USB port and
appear as large removeable disk drives. You can copy
files to them as if they were a disk, remove the
memory key and carry the data away on your key
chain! They are exceptionally useful little beasties. The
death of the floppy disk is imminent.
What is BIOS?
Basic Input/Output System (BIOS)
is a set of program
instructions that provide startup information for a computer, and
acts as a go
between between an operating system and the
hardware in a computer. The BIOS is usually located in flash
memory (EEPROM) on the motherboard. When a PC is started,
the BIOS runs a power
test (POST). It then tests the
system and prepares the computer for operation by searching for
other BIOSs on expansion boards (e.g. video card, hard disk
controller) and remembering where they are, so the computer can
use the plug
in devices later. It then loads the operating system
and passes control to it.
What is a keyboard?
What is the most common type?
lets you input data into an info system. The most common
key layout is called QWERTY (named after the first keys on the top
alphabetic row of the keyboard.) QWERTY is a standard, but is very
inefficient: it was in fact
designed to slow down fast typists in
the early days of mechanical typewriters which tended to jam if the user
typed too quickly.
The alternative key layout is Dvorak which places the most commonly
used keys on the middle "home" row so the typist would not need to
move around the keyboard nearly as much. Alas, Dvorak came too late
and QWERTY, as horrible as it was, became the standard and still is.
Explain the term ‘cache’.
Cache is a storage place (buffer or bucket) that
exists between two subsystems in order for data to
be accessed more quickly to increase performance.
Performance is increased because the cache
subsystem usually has faster access technology
and does not have to cross an additional bus.
What is an expansion slot?
are sockets that expansion cards like network
cards, sound cards, graphics cards can be plugged into. There
have been various types of slots over the years to cater for
increasingly complex expansion cards. The earliest cards were
ISA, then came EISA, then PCI and AGP (which have special
priority access to the CPU
AGP is used by fast graphic
All expansions slots connect to a bus so data can travel
between subsystems and the CPU.
What is the purpose of the power supply?
provides the electricity needed by the
motherboard and different components in the computer. It
usually provides a series of power leads carrying 12 volts or 5
volts. A special lead feeds the motherboard and other leads
power the disk drives. The power supply is a sealed cube about
12cm on each side and has a fan in it to cool itself down.
What is a ‘bit’?
A bit is a binary 1 or 0
Binary numbers and arithmetic let you represent any amount you
want using just two digits: 0 and 1. Here are some examples:
Decimal 1 is binary 0001
Decimal 3 is binary 0011
Decimal 6 is binary 0110
Decimal 9 is binary 1001
What are communication ports?
Computers need a way to connect to external
devices, such as mice, monitors, printers, scanners
etc. The sockets on the back (and front) of computers
and are designed to allow peripheral
(external) devices to be attached to a system to
enhance its abilities. There are several different types
What is a touchpad?
are common on laptop computers. A
little smaller than a credit card, they respond to
finger touches. Dragging a finger across the pad
is like moving the mouse. Tapping the touchpad
acts like the mouse buttons. They are
surprisingly accurate and intuitive to use and
they are virtually indestructible.
What is a computer network?
are no more than computers
that are linked together so they can communicate.
Network size is in describing a network: there are local area
networks (LAN) , metropolitan area networks (MAN) and wide
area networks (WAN). When WANs get interconnected, you
have the Internet.
What is a NIC?
To connect a computer to a network, you need a
network interface card (NIC) in it. This is what the
network cable gets plugged in to. Computers can
be linked together with cables or the connection
can be wireless (through radio communication).
What is a device driver?
are the go
between: a "handler" that accepted generic
commands from the operating system and translated the generic
command into the specific language spoken by the device. This handler
is a small program, and is known as a driver: all hardware devices need
drivers (which is why you nearly always get a disk with each hardware
gadget you buy; the driver for the device is on the disk.) Devices such as
printers, modems, scanners, video cards all do their work in their own
way; they have their own set of commands they understand. However,
regardless of how they work internally, they must all connect to the same
operating system and work properly. The commands sent from the
operating system to the driver are "universal" commands: the OS does
not care what language the printer speaks. It just tells the driver what it
What is the purpose of switches and hubs?
Networks need to connect cables together. They use
to do this.
A hub is a device that lets a single network cable to split into multiple cables
(network devices such as computers, printers, other
Hubs and switches do essentially the same job. A PC's network card is
connected by cable to a hub or switch. The hub/switch is in turn connected
to the file server. Switches are rather more intelligent and efficient than hubs
and reduce the amount of network traffic.
When the file server transmits a message to a PC via a hub, the hub sends
the message to
PC connected to it. A switch, however, knows which
PC the message is meant for and directs the message just to that PC.
The other PCs on the network aren't flooded with irrelevant traffic.
Complete the following:
Bits in a byte
Bytes in a Kilobyte
Kilobytes in a Megabyte
What is a protocol?
The rules used by the network for sending data is called a
. Protocols are to computers what language is to
humans. For two devices on a network to successfully
communicate, they must both understand the same protocols.
A combination of two packet
switching protocols (Transport
Communications Protocol and Internet Protocol) that forms the
basis of all Internet communications.
TCP is the protocol used to break messages into packets in the
sending computer, and also to reassemble them in the
What is a printer?
Name more than one type of printer.
. They are an output device.
There are four main types of printer:
expensive to buy, cheap to run, fast, high resolution, quiet(ish), page
cheap to buy, expensive to run, slow, medium to high resolution, quiet,
: medium expense to buy, medium expense to run, LOUD, low
cheap to buy, expensive to run (paper cost), medium speed, low
resolution, silent, character