IT Gr10 THEORY MEMO NOV 2014
Question 1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
B
C
C
A
A
B
B
D
B
B
(10)
Question 2
2.1 True
2.2 False, the data structure which can hold many values at once in Scratch is
called a list.
2.3 True
2.4 True
2.5 False, global variables can be used in all the procedures in the unit.
2.6 True
2.7 False, hard drives are mechanical storage devices.
(10)
Question 3
3.1
Safari, Chrome
(1)
3.2
Intel
(1)
3.3
256 GB
(1)
3.4
Any two facts:
(2)




Solid State Drives use a specific type of electronical memory that can
keep data even though the power is off.
They are faster than mechanical drives.
They are more expensive.
They have much less space than a magnetical hard drive.
3.5
Yes, it has a retinal display which would make the image much clearer. You
will, thus, see the picture in better quality.
(2)
3.6
OS X Maverick
(1)
3.7
FIVE functions of an operating system:





(5)
Provides an interface
Process and task management
Memory management
Input/Output management
Drive management
3.8.1 Thunderbolt
(1)
3.8.2 It is used for the power cable, but it works with a magnet. Therefore, the
computer cannot fall off a desk if someone falls over the power cable,
because the magnet pulls out and the computer stays in the same place. (2)
3.9
An inkjet printer, it provides the best quality for colour photos.
3.10 Any two:




(2)
(2)
It is mobile, so he can do his work wherever he is.
It is much cheaper than the iMac.
It has battery power, so if the power goes out he would still be able to work
for at most eight hours.
Any other relevant answer.
Question 4
4.1
A network is a collection of computers and/or devices that are connected
through some kind of communication medium. Mostly used for communication. (2)
4.2
Any three:







4.3
(3)
Fast, effective communication
Sharing of peripherals
Centralising of data
Transfer of files
Leisure time
Increased control and security
Variety of access
A NIC is used to connect the network cable (UTP) to the computer.
A switch is a device that is used to connect computers in a network so that
communication can take place.
(2)
4.4
Shortcomings of communication mediums:
Any two shortcomings:
(4)
Signal weakening
UTP is susceptible to
signal weakening.
Maximum length of cable
before signal weakens is
100 m.
Eavesdropping
UTP is sensitive to
eavesdropping, but the
fact that the cable is
turned helps to counteract
eavesdropping.
The magnetical fields in and around cables near to
each other can interfere with data transfer and cause
crossed lines. Data can become lost or corrupt.
UTP is sensitive to EMI,
Optical fibre cables are
but the fact that the cable not influenced by EMI or
is turned helps to
current fluctuations. They
counteract this sensitivity. can be used in places like
factories where
magnetical fields can
affect communication.
Crossed lines
Electromagnetical
interference (EMI)
4.5
Optical fibre cables is less
prone to signal weakening
than UTP cables.
Can transfer data over
long distances (measured
in km).
Optical fibre cables are
immune against
eavesdropping.
Any three differences:
Peer-to-peer
All computers are equal and perform the
same communication functions.
No server is needed.
All computers must have big storage
space, lots of memory (at least 4GB)
and powerful processors.
The software is cheaper, because it is
included with the operating system.
Only for small number of computers.
Little technical skills needed for setup.
Sometimes slow performance
Security is limited
Because there is no server, work
stations can be used as stand-alone
computers if problem with network
arises.
No network administrator needed
(6)
Client-server
A computer in the network is a client or
a server.
A server is needed.
Only the server has to be powerful. The
rest of the computers does not
necessarily have to have big storage
space and powerful processors.
Needs a network operating system.
For large number of computers.
Must be set up by a person with the
technical skills
Faster performance
Security much more sophisticated
If there is a problem with the server, no
computer will work.
Needs network administrator
4.6
Any three:





(3)
To manage a network you need a network administrator.
Strict security rules are needed and access rights to folders must be
strictly controlled.
Malware like viruses can quickly spread via a network.
If a network problem arises it may mean that none of the users can work or
use the added peripherals, like printers.
A central error on the network, like the server crashing, can lead to the
loss of data.
[20]
Question 5
5.1
Overflow
5.2
Truncing
5.3.1 101112 = (1 x 24) + (0 x 23 ) + (1 x 22 ) + (1 x 21 ) + (1 x 20 )
= (1 x 16) + (0 x 8) + (1 x 4) + (1x2) + (1x1)
= 16 + 0 + 4 + 2 + 1
= 23
(2)
5.3.2 100111012
= (1 x 27) + (0 x 26) + (0 x 25) + (1 x 24) + (1 x 23) + (1 x 22) + (0 x 21) + (1 x 20)
= (1 x 128) + (0 x 64) + (0 x 32) + (1 x 16) + (1 x 8) + (1 x 4) + (0 x 2) + (1 x 1)
= 128 + 0 + 0 + 16 + 8 + 4 + 0 + 1
= 157
(2)
5.3.3 110011112
= (1 x 27) + (1x 26) + (0 x 25) + (0 x 24) + (1 x 23) + (1 x 22) + (1 x 21) + (1 x 20)
= (1 x 128) + (1 x 64) + (0 x 32) + (0 x 16) + (1 x 8) + (1 x 4) + (1 x 2) + (1 x 1)
= 128 + 64 + 0 + 0 + 8 + 4 + 2 + 1
= 207
(2)
5.4.1 1246 = 100110111102
(2)
1246 ÷ 2 = 623
res 0
623 ÷ 2
= 311
res 1
311 ÷ 2
= 155
res 1
155 ÷ 2
= 77
res 1
77 ÷ 2
= 38
res 1
38 ÷ 2
= 19
res 0
19 ÷ 2
=9
res 1
9÷2
=4
res 1
4÷2
=2
res 0
2÷2
=1
res 0
1÷2
=0
res 1
5.4.2 1489 = 101110100012
(2)
1489 ÷ 2 = 744
res 1
744 ÷ 2
= 372
res 0
372 ÷ 2
= 186
res 0
186 ÷ 2
= 93
res 0
93 ÷ 2
= 46
res 1
46 ÷ 2
= 23
res 0
23 ÷ 2
= 11
res 1
11 ÷ 2
=5
res 1
5÷2
=2
res 1
2÷2
=1
res 0
1÷2
=0
res 1
5.5.1 486 = 1E616
(2)
486 ÷ 16 = 30 res 6
30 ÷ 16
=1
res 14
1 ÷ 16
=0
res 1
5.5.2 867 = 36316
(2)
867 ÷ 16 = 54 res 3
54 ÷ 16
=3
res 6
3 ÷ 16
=0
res 3
5.6.1 F4816
= ( F x 162) + (4 x 161) + (8 x 160)
= (15 x 256) +(4 x 16) + (8 x 1)
= 3840 + 64 + 8
= 3912
5.6.2 756DF
(2)
= (7 x 164) + (5 x 163) + (6 x 162) + (D x 161) + (Fx160)
= 458752 + 20480 + 1536 + 208 + 15
= 480991
(2)
Question 6
6.1
TASK: Calculate the percentage of the mark out of 60 and if it is a distinction.
✓
BEGIN
Ask ‘Type in the mark achieved’ ✓
Get mark ✓
Perc = Punt/60 * 100 ✓
Display “Mark: ’ , Mark ✓
Display ‘Percentage: ’ , Perc ✓
If (Perc >= 80) ✓
Display: ‘You have a distinction’ ✓
EINDE
(8 x ½ = 4)
6.2
procedure TfrmRegister.btnAnswerClick(Sender: TObject);
begin
rAmount := iNumItems * 10 ;
memCashSlip.Lines.Add('Total : ' + FloatToStrF(rAmount,ffCurrency, 8, 2)) ; ✓✓✓
end;
procedure TfrmRegister.btnShowChangeClick(Sender: TObject);
var
rPaid, rChange : real ;
begin
rPaid :=StrToFloat(edtPaid.Text); ✓✓
rChange := rPaid - rAmount ; ✓✓
memCashSlip.Lines.Add('Paid : ' + FloatToStrF(rPaid,ffCurrency, 8, 2)) ; ✓✓
memCashSlip.Lines.Add('Change : ' + FloatToStrF(rChange,ffCurrency, 8, 2)); ✓✓
end;
6.3
(10)
The file cannot be opened by any program on your computer. You may search
the internet or find a suitable program from a list of installed programs.
(1)
Question 7
7.1
ADSL is a permanent digital connection that uses a telephone line. The
telephone line has two channels: one channel is used for the telephone and
the other to connect to the internet. The line is rented through a
communication supplier like Telkom.
(3)
7.2
To connect to the internet you need an ISP. An ISP is a company that has a
fast, permanent internet connection. This company sells internet access to
individuals or organisations for a monthly fee.
(2)
7.3
Bandwidth is the rate of data transfer. It refers to the total amount of data that
can be transferred from one point to another in a given time period. It is
usually measured in Kbps or Mbps.
(2)
7.4.1 A worm is malware that spreads itself over the network – usually through
emails – without the user even knowing that he\she has executed or run the
infected program or file. A worm can reproduce itself. They can reproduce
themselves in such way to fill up your hard drive capacity. This causes the
computer to become very slow and the computer may even stop working
(crash).
(2)
7.4.2 A Trojan is a harmful program that makes itself out as a useful program. You
are tricked into opening and using it. It can be added to email attachments.
Most email programs does not allow .exe files as attachments to emails. (2)
7.4.3 Pharming is similar to phishing, but the user does not receive an email
message. This is an identity theft/fraud scheme where the user’s computer is
infiltrated in such a way that a user gets redirected to fake websites even
though he\she enters the correct URL in the browser. The criminal can then
utilise any gathered data.
(2)
7.5
See if the URL starts with HTTPS.
See if a lock appears next to the URL when the website is loaded.
(2)
7.6
Phishing
(1)
7.7
Application software and system software
(2)
7.8
Chain stores have many branches across the country. A POS system is a
Point of Sale system which manages inventory, finances and payroll systems.
It uses barcodes and scanning to process the total sales faster and more
efficiently.
(2)
7.9
It means that a computer consists of various separate parts which makes
maintenance and upgrading much easier than if it would have consisted out of
just one piece.
(2)
7.10 A Wiki is a website which can be edited and changed by users.
(1)
7.11 Ergonomics is the study of people’s working environments and the design of
these environments to work for them and be as comfortable and safe as
possible.
(2)
[25]
TOTAL: 120