CS Year 11
Exam questions
1.


Exam-Style Questions
1a. NAND gate
b. OR gate
2a. A      B      C
      0       0      

Two different kinds of loop

For Loop - is run a certain number of times
for i in range(10)

While Loop - is run while a certain condition is true
while x > 20:

Algorithm Planning and Design

Problem: Read in 10 numbers and display their total

Think about input - processing and storage - output.

We need to instruct the processor about a "Running Total"

We will start by setting the total to 0. We will set the count to zero. The count is how many numbers we have added.

Top Down Design Method

Total 10 numbers

Initialise values for running total       Input and process 10 numbers*       Display answer

                     |                                                                      |

               ________                                                             |

               |               |                                               ___________________

       Total=0       Count=0                                     |                 |                    |

                            Input a number    add number to total    add 1 to cart

*Process the numbers 10 times (repeat) enter a single number and add it to the running total.

Internet Backbone

      |       |          |      

NSP    NSP   NSP  - Network Service Provider (Govt)

|         |

ISP ISP   - Internet Service Provider (Electronic Post Office)

       |

End User

Search Engine - Google

Web Browser - Safari

FTP - File transfer protocol is used to transfer or upload files to the internet

URL - Uniform resource locator, this is the address of a webpage or website.

HTTP - Hyper Text Transfer Protocol, would be used to establish the connection.

 

Anti-virus software: There are a number of malicious software programs that can cause damage to computers. These include viruses, worms, zombies, Trojans and Spybots.

Anti-virus software is designed to detect and block attacks from malware. Some operating systems have their own inbuilt anti-virus software.

Firewall: A firewall is software that will block unexpected connections coming in to the network. Most operating systems include a firewall.

Secure passwords: When more than one person uses a network it is important to have user IDs and passwords. Only someone with a login and password can access that network. It also helps the network manager trace unusual activity to a specific user.

Access levels: In a large company or school, many people will be using computers on the same network. General users will not have the ability to download any software they want or to make changes to any part of the system, as that could affect other users.

The more people have access to sensitive parts of the network, the more likely it is that a hacker or a virus might be able to cause damage.

Encryption: Any message sent over a network can be intercepted. Encryption is a method of changing the original numbers so that they are hidden or disguised. A way of encrypting something could be by using the Caesar Cipher algorithm. In this method, each letter of the alphabet is simply replaced by another letter of the alphabet that might be one or more positions away. 

Acceptable use policy (AUP): An AUP states how the network might be used - what is and isn't acceptable.

 

Archiving: Networks often have to store a lot of data. A good archiving strategy takes old, non-essential data and puts it somewhere safe. An archiving policy helps decide when to move data, where it should be kept, and how to get it back if needed. 

 

Cyber attacks: Cyber attacks and cyber terrorism are ways of attacking companies and organisations online. There are frequent attacks on the government and organisations in the UK.

Hacking: Hackers attempt to break into networks and steal private information. IT security specialists are employed by companies to hack their own networks and find security faults or weaknesses.

 

Phishing: Getting a user to enter personal information via a fake website.

Low-level languages

A compiler program translates all the high-level source code into object code by a process known as 'compilation'. Compilation must be completed before the program can run. An analogy is translating text from English into another language and then giving the complete translated text to someone to speak.

An interpreter translates a high-level language program in a very different way. The interpreter runs directly on the target processor, usually analysing one source code statement at a time and running appropriate subroutines to give effect to, or 'execute' it.

trfgh

6   5   4  3   2  1
4   2   1  9   2  3
24 10 4 27  4  3
24+10+4+27+4+3=
72/11 = 6.54
Not Valid





6   5   4 3 2   1
8   2   0 1 5   6
48 10 0 3 10  6
48+10+0+3+10+6=
77/11 = 7
 Valid
 





6   5 4  3  2 1
5   0 2  4  1  _
30 0 8 12 2
52 + 3 = 55
Check digit = 3










1. Transposition error
2. Simply type in the wrong digit/letter





















 1. DVD-RAM can hold data for longer periods of time
2. DVD-RAM is more compatible than DVD+RW

3.

4a. 16:49
b. 0001
    0111
    0010
    1001
c. If the present time and the binary number match up to the time set (08:00) the alarm will be set to trigger.

5a. Yes
b. No
c. Errors were corrected by resending the byte back to the sender of the data

6a. Temperature and oxygen content monitor
b. The micro-processor is used to monitor the temperature and the oxygen content and if the micro-processor detects that either the temperature sensor or the oxygen content monitor detects that they do not meet the requirements then the valve will work and increase the temperature and the oxygen content of the water and once it meets the requirements preset then the valve will shut off and stop increasing the temperature and oxygen content.
c. The safeguards used by the micro-processor to stop the temperature rising to high will use the temperature sensor to monitor that once it reaches the preset time the valve will shut off and stop increasing the temperature.

7. HTML: 1
    Browser: 2
    MAC address: 6
    IP address: 4
    http: 3
    Internet Server: 5

7b. Some websites make the request to enable cookies because it stores the data of the users previous information entered into the website.

8ai. A byte is a unit of digital information in computing and telecommunications that most commonly consists of 8 bytes
ii. A gigabyte is 1,000,000 bytes and does the same job but on a much larger scale

b. 1. Flash memories can store large amounts of data while CD's can only store under a gigabyte
    2. On flash memories you can add, erase and modify the data stored by it and on a CD-RW you can only write over the data 3 or 4 times.

9a. A buffer
b. Interrupt

10ai. Hello World
ii. Vmilozgu Pnwgyng
b. So if the data is hacked, the hacker cannot access the key and then access all the data that has been hidden and sent privately.

11. Anti-spyware software - E
      Anti-virus software - C
      Back-up files - A
      Encryption - D
     Passwords and a firewall - B

12a. B is a high level language
b. It takes shorter time to code, more systems understand it and we can see what we're doing.
c. It is simpler to learn
d. 1. A compiler program runs the program and then gives an error report at the end
2. An interpreter program runs the program until an error is found, if an error is found the program stops until the error is fixed.

13ai.Location 1: 01000001
        Location 2: 01000011
ii. Location 1: 41
    Location 2: 43
b. 64147 = FA97