Time allowed: 1 hour 30 minutes
Please write clearly in black ink. Do not write in the barcodes.
Computers use binary to represent different types of data.
(a) Complete the sentences about sound sampling using the words from the list below.
Not all words will be used.
| Analogue | Amplitude | Binary | Digital |
| Frequency | Hertz | Pitch | Sample Rate |
Sound is recorded as an wave. To be processed by a computer, it must be converted into a signal.
The is the number of samples taken per second. This is measured in .
(b) Complete the table by converting the numbers between 8-bit Binary, Denary, and Hexadecimal.
| Denary | 8-bit Binary | Hexadecimal |
|---|---|---|
| 43 | 2B | |
| 170 | 10101010 | |
| FF |
(c) Add the following two 8-bit binary numbers. Show your working.
(d) Perform a binary shift of 2 places to the left on the binary number 00001100.
Binary result:
State the effect this shift has on the denary value of the number.
(e) Explain one difference between the ASCII and Unicode character sets.
A small estate agent business is setting up a Local Area Network (LAN) for its office.
(a) The office has 10 computers that need to connect to the internet.
Identify two pieces of hardware, other than cables, that are required to create this LAN and connect it to the internet.
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(b) The manager is deciding between a wired or wireless network.
Give two benefits of using a wired connection instead of a wireless connection.
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(c) The network uses the TCP/IP protocol stack.
Tick (✓) one box in each row to match the protocol to its description.
| Description | HTTP | IMAP | SMTP |
|---|---|---|---|
| Retrieves emails from a server. | |||
| Sends emails to a mail server. | |||
| Transmits web pages to the client. |
(d) When a user types a URL (e.g., www.ocr.org.uk) into a browser, the DNS is used.
Describe the steps taken by the Domain Name Server (DNS) to display the website.
Wearable technology, such as smartwatches and fitness trackers, collects large amounts of personal health data (e.g., heart rate, location, sleep patterns).
Some health insurance companies are offering reduced prices to customers who share this data with them.
Discuss the impacts of this technology and data sharing.
You should consider:
Computers are vulnerable to various security threats.
(a) Identify the threat described in each box below.
| Description | Threat Name |
|---|---|
| Software that records every keystroke made by a user to steal passwords. | |
| A trial-and-error method used to guess a password by trying all possible combinations. | |
| Malicious code inserted into a website’s input box to modify the underlying database. |
(b) Explain how a Firewall helps to prevent unauthorised access to a network.
(c) The operating system uses a User Interface to allow humans to interact with the computer.
Tick (✓) one box to identify the type of interface that uses windows, icons, menus, and pointers.
(d) Most modern operating systems support multitasking.
Describe how the operating system manages memory and the CPU to allow multitasking to occur.
(e) Defragmentation is a type of utility software.
Explain why a computer's performance might improve after defragmentation is run.
A computer uses the Von Neumann architecture.
(a) The CPU contains several registers.
Describe the purpose of the Memory Address Register (MAR) and the Memory Data Register (MDR) during the Fetch-Execute cycle.
MAR:
MDR:
(b) A washing machine uses an embedded system to control the wash cycle.
(i) Identify two characteristics of an embedded system that make it different from a general-purpose computer.
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(ii) Explain why the washing machine uses ROM (Read Only Memory) as part of its embedded system.
(c) Explain how increasing the cache size affects the performance of the CPU.
A professional video editor creates and stores high-definition video files.
(a) The editor needs to buy a new secondary storage device to archive completed projects for long-term storage (10+ years).
They are choosing between a Magnetic Hard Disk Drive (HDD) and a Solid State Drive (SSD).
Identify the most appropriate device for this scenario and justify your choice. You should refer to the specific requirements of archiving.
Device:
Justification
(b) A sound recording is 100 seconds long. It is sampled at 20,000 Hz with a bit depth of 16 bits.
Calculate the file size in megabytes (MB). You must show your working.
(Hint: 1 byte = 8 bits, 1 megabyte = 1,000,000 bytes)
Answer: MB
(c) The video editor considers using Cloud Storage to share files with clients.
Describe two drawbacks of using Cloud Storage for large video files.
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A university computer lab has 50 computers connected in a network.
(a) The computers sometimes run slowly when students have many programs open at once.
Explain how Virtual Memory is used when the RAM is full and how this affects the performance of the computer.
(b) Students store their coursework on a central server.
Identify the type of network model used in this lab.
Justify your choice.
(c) The university needs to reduce the file size of the student data.
Describe the difference between Lossy and Lossless compression.
If you need extra space use this lined page. You must write the question numbers clearly in the margin.