9618/13 · May/June 2023
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Write the logic expression for this truth table:
| A | B | C | X |
|---|---|---|---|
| 0 | 0 | 0 | 1 |
| 0 | 0 | 1 | 1 |
| 0 | 1 | 0 | 0 |
| 0 | 1 | 1 | 0 |
| 1 | 0 | 0 | 1 |
| 1 | 0 | 1 | 1 |
| 1 | 1 | 0 | 0 |
| 1 | 1 | 1 | 0 |
Complete the truth table for this logic circuit:
| A | B | C | Working space | X |
|---|---|---|---|---|
| 0 | 0 | 0 | ||
| 0 | 0 | 1 | ||
| 0 | 1 | 0 | ||
| 0 | 1 | 1 | ||
| 1 | 0 | 0 | ||
| 1 | 0 | 1 | ||
| 1 | 1 | 0 | ||
| 1 | 1 | 1 |
A university has two sites. Each site has several computer rooms. The computers are all connected as a WAN (wide area network).
Identify two differences between a WAN and a LAN (local area network). 1 ................................................................................................................................................ ................................................................................................................................................... 2 ................................................................................................................................................ ...................................................................................................................................................
The network uses different topologies in different areas of the sites. In one building there are five computers connected in a mesh topology. Describe what is meant by a mesh topology.
Give two advantages of using a mesh topology instead of a bus topology. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ...........................................................................................................................................
The computers in one room are set up as thin-clients in a client-server model. Describe the role of the different computers in this model.
Students can connect their devices to the university network using cables or a wireless connection. Explain the benefits to the students of allowing them to use both wired and wireless connections.
One site has split the network into several subnetworks. An IP address in a subnetwork is divided into two parts. Identify and describe the two parts of an IP address in a subnetwork.
A mobile telephone is used to record a video.
The mobile telephone has a touchscreen. There are different types of touchscreen. Complete the description of the principal operation of touchscreens. A .............................................................. touchscreen has two layers. When the user touches the screen, the layers touch and a .............................................................. is completed. A .............................................................. touchscreen has several layers. When the top layer is touched, there is a .............................................................. in the electric current. A microprocessor identifies the .............................................................. of the touch.
The mobile telephone uses a built-in digital camera to record the video. The digital camera automatically focuses on the faces of people. Explain how Artificial Intelligence (AI) is used by the camera to automatically focus on the faces of people.
The video includes a sound recording. Describe how sound is represented in a computer.
A second video is recorded. The sound in the second video needs to be more precise. Explain the reasons why increasing the sampling rate and the sampling resolution will improve the precision of the second recording. Sampling rate .................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... Sampling resolution ........................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...........................................................................................................................................
A shop rents cars to customers. The shop uses a relational database to store information about the rentals.
Describe two ways in which a relational database addresses the limitations of a file-based approach. 1 ................................................................................................................................................ ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... 2 ................................................................................................................................................ ................................................................................................................................................... ................................................................................................................................................... ...................................................................................................................................................
Complete the table by writing the missing term or description for each database feature.
| Term | Description |
|---|---|
| ........................................ | |
| ........................................ | |
| Tuple | |
| Secondary key | |
| ........................................ | A field in one table that is linked to a primary key in another |
| ........................................ | table. |
The car rental database is not normalised. The current database design is: Write a normalised database design for this database. All tables must be in Third Normal Form (3NF). Use the field names given and underline the primary key fields.
The data is validated and verified when it is entered into the database. The car registration number must be: 1 letter, followed by 3 numbers, followed by 2 letters. For example, A123AA is valid but A12AA is invalid. One way that a registration number can be validated is by using a presence check to make sure the registration number has been entered. Describe two other ways that the car registration number can be validated. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ...........................................................................................................................................
Describe two ways that the car registration number can be verified when it is entered into the database. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ...........................................................................................................................................
State why the car registration number might be incorrect even after it has been validated and verified.
A programmer is developing a computer game in a high-level language to sell to the public.
The programmer uses both an interpreter and a compiler at different stages of the development of the program. Explain the reasons why the programmer uses an interpreter while writing the program code.
Explain the reasons why the programmer uses a compiler when the program has been written.
The programmer needs to publish the game under a software licence so that it can be sold to the public. Identify the most appropriate type of software licence for the game and justify your choice. Licence ..................................................................................................................................... Justification ............................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...................................................................................................................................................
Data needs to be kept secure when stored on a computer and during transmission over a network.
Explain how a digital signature is used to authenticate a digital document during transmission over a network.
Complete the table by identifying and describing two types of software that can be installed on a computer to prevent threats over a network.
| Type of software | Description |
|---|---|
| ……………………….. | ........................................................................................................ |
| ……………………….. | ........................................................................................................ |
| ........................................................................................................ | |
| ……………………….. | ........................................................................................................ |
| ……………………….. | ........................................................................................................ |
| ........................................................................................................ |
A computer stores data in binary form.
Draw one line from each description to its matching denary value.
| Description | Denary value |
|---|---|
| The smallest integer that can be represented in 8-bit two's complement. | -127 |
| 127 | |
| -255 | |
| The largest integer that can be represented in 8-bit two's complement. | -128 |
| -256 | |
| 256 | |
| The largest unsigned integer that can be represented in 8 bits. | 128 |
| 255 |
The computer has a Control Unit (CU), system clock and control bus. Explain how the CU, system clock and control bus operate to transfer data between the components of the computer system.
Complete the table by writing the register transfer notation for each stage of the Fetch-Execute (F-E) cycle given in the table.
| Stage description | Register transfer notation |
|---|---|
| The Program Counter (PC) is incremented | ....................................................................... |
| The data in the address stored in the | |
| Memory Address Register (MAR) is copied | |
| to the Memory Data Register (MDR) | ....................................................................... |