0478_s16_qp_13
A paper of Computer Science, 0478
Questions:
12
Year:
2016
Paper:
1
Variant:
3
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1
Some software can be described as free, freeware or shareware. Tick (✓) the appropriate boxes in the table below to show which features apply to these three types of software. Software feature Free Freeware Shareware Software source code can be freely accessed and modified as required All the features of the full version of the software are not made available; the full version needs to be purchased first The original software is subject to all copyright laws It is possible to distribute modified versions or copies of the software to friends and family
4. Software  →  4.1. Types of software and interrupts
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3
Five sensors and five applications are shown below. Draw a line to link each sensor to its most appropriate application. Sensor Application Light sensor Monitor the pollution levels in a river Moisture sensor Control the switching off and on of street lights Gas sensor Detect intruders breaking into a building pH sensor Monitor the amount of water left in clothes in a dryer Pressure sensor Monitor acidity levels in the soil in a greenhouse Automatic doors in a building are controlled by the use of infrared sensors and a microprocessor. Describe how the sensors and the microprocessor are used to automatically open a door as a person approaches.
3. Hardware  →  3.2. Input and output devices
6. Automated and emerging technologies  →  6.1. Automated systems
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4
Nikita wishes to print out some documents and connects her printer to the computer using one of the USB ports. Identify what type of data transmission is being used. Give three reasons for using a USB port. The printer runs out of paper while it is printing the documents. A signal is sent to the processor to request that the problem is dealt with. Name this type of signal. State one suitable application for each printer below. A different application must be given for each printer. Inkjet printer 3D printer Name another type of printer and describe one way in which it is different from the printers named in part . Give an application for this printer. Type of printer Description Application
3. Hardware  →  3.2. Input and output devices
2. Data transmission  →  2.1. Types and methods of data transmission
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5
A computer-controlled machine produces plastic sheets. The thickness of each sheet must be within a certain tolerance. The sheets are kept below 50 °C as they move over rollers at 10 metres per second. Three parameters need to be monitored all the time. Parameter Description Binary value Conditions D sheet thickness thickness of sheet in tolerance thickness of sheet out of tolerance S roller speed roller speed = 10 metres/second roller speed <> 10 metres/second T temperature temperature = 50 °C An alarm, X, will sound if: thickness is in tolerance AND (roller speed <> 10 metres/second OR temperature >= 50 °C) OR roller speed = 10 metres/second AND temperature >= 50 °C Draw a logic circuit to represent the above monitoring system. D S X T Complete the truth table for the monitoring system. D S T Working Space X
10. Boolean logic  →  10. Boolean logic
7. Algorithm design and problem-solving  →  7. Algorithm design and problem-solving
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7
Each seat on a flight is uniquely identified on an LCD above the seat. For example, seat 035C is shown as: The first three characters are digits that represent the row. The fourth character is the seat position in that row. This is a single letter, A to F, that is stored as a hexadecimal value. Each of the four display characters can be stored in a 4-bit register. For example, 0 and C would be represented as: C: 0: Show how the 4-bit registers would store the remaining two characters, 3 and 5. Identify which seat is stored in the following 4-bit registers.
1. Data representation  →  1.1. Number systems
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8
A bank offers an online service to its customers. The bank has developed a “SafeToUse” system that asks each customer to enter four randomly chosen characters from their password each time they log in. The customer selects these four characters from drop-down boxes. For example: Please select the 2nd character 5th character 6th character 8th character Explain why it is more secure to use drop-down boxes rather than entering characters using a keyboard. Give a reason why the system asks for four characters chosen at random. Biometrics is an additional form of security. Give two examples of biometrics.
5. The internet and its uses  →  5.3. Cyber security
6. Automated and emerging technologies  →  6.1. Automated systems
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9
Check digits are used to ensure the accuracy of entered data. A 7-digit number has an extra digit on the right, called the check digit. digit position: digit: – – – – – – – – check digit The check digit is calculated as follows: • each digit in the number is multiplied by its digit position • the seven results are then added together • this total is divided by 11 • the remainder gives the check digit (if the remainder = 10, the check digit is Calculate the check digit for the following number. Show all your working. 4 2 4 1 5 0 8 … Check digit An operator has just keyed in the following number: 3 2 4 0 0 4 5 X Circle below correct if the check digit is correct OR incorrect if the check digit is incorrect. correct incorrect Explain your answer.
2. Data transmission  →  2.2. Methods of error detection
7. Algorithm design and problem-solving  →  7. Algorithm design and problem-solving
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10
Six security issues and six descriptions are shown below. Draw a line to link each security issue to its correct description. Security issue Description illegal access to a computer system without the owner’s consent or knowledge software that gathers information by monitoring key presses on a user’s keyboard; the data is sent back to the originator of the software malicious code installed on the hard drive of a user’s computer or on a web server; this code will re-direct the user to a fake website without the user’s knowledge creator of code sends out a legitimate-looking email in the hope of gathering personal and financial information from the recipient; it requires the user to click on the link in the email or attachment a message given to a web browser by a web server; it is stored in a text file; the message is then sent back to the server each time the browser requests a page from the server program or code that replicates itself; designed to amend, delete or copy data or files on a user’s computer; often causes the computer to crash or run slowly Pharming Phishing Viruses Hacking Spyware Cookies
5. The internet and its uses  →  5.3. Cyber security
5. The internet and its uses  →  5.1. The internet and the world wide web
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11
Four examples of optical storage media are: • DVD-RW • DVD-RAM • CD-ROM • Blu-ray disc The table below shows four features of optical storage media. Tick (✓) the appropriate boxes in the table to indicate which of the features apply to each example of optical storage media. Single track Many concentric tracks Blue laser used to read/ write data Red laser used to read/ write data DVD-RW DVD-RAM CD-ROM Blu-ray disc Solid state drives (SSD) are replacing hard disc drives (HDD) in some computers. Give three reasons why this is happening. Explain why many web servers still use hard disc drive (HDD) technology.
3. Hardware  →  3.3. Data storage
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