Computer Science Paper 1
25 test answers
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Even parity check
answer
last number should be 1 to pass the check, otherwise fail.
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Odd parity check
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last number should be 0 to pass the check, otherwise fail.
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The conditions in a fish tank are being controlled using sensors and a microprocessor. To keep the fish healthy, the temperature must be at 25°C and the oxygen content needs to be 20 ppm (parts per million). The tank contains a heater and an oxygen inlet controlled by a valve. Name the two sensors used in this application.
answer
1) Temperature sensor 2) Oxygen sensor
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What safeguards are needed to stop the fish tank temperature rising too high?
answer
thermometer, alarm sound
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MAC address
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unique ID for a network interface card
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what does Internet Server do
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computer that responds to requests to provide information and services over the Internet
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http
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defines how messages are transmitted and formatted over the Internet
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Ahmed sees the message \"Set your browser to accept cookies\". Explain why some websites make this request.
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1) to enable logon information to be kept on his computer 2) to provide pages customised for Ahmed the next time he logs on
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Computer memories are measured in terms of the number of bytes. What is meant by the term byte?
answer
it is a unit of data
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The number of bytes in a Gigabyte can be written as 2x What is the value of x?
answer
30
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Flash memories and CD-RWs are used as backing media for computers. Give two differences between these two media.
answer
Flash memory plugs directly into the USB port. CD-RW is Optical Media. CD-RW has slower access speed - flash memory is faster
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Andrew sends a large document to a printer. State the name for the area of memory used to store temporarily the data being sent to the printer.
answer
RAM
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The printer runs out of paper during the printing job. A signal is sent back to the computer to stop temporarily its current task. Name this type of signal.
answer
interrupt signal
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The quick brown fox jumps over the lazy dog. Decode this cypher text message: Agbbm Pmubq
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Hello World
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What is meant by SSL?
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Secure Socket Layer
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How does SSL keep the copy of the key secret during transmission?
answer
the key itself is encrypted using strong encryption
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Give one benefit of writing code in a high-level language.
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easier to understand for programmer/closer to English
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Give one benefit of writing code in a low-level language.
answer
can be written to run faster
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High-level languages can be compiled or interpreted. Give two differences between a compiler and an interpreter.
answer
1) compiler translates whole program in one go / interpreter translates and executes line at a time 2) compiler produces list of all errors / interpreter produces error message each time an error is encountered
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The following machine code instruction is stored in a location of main memory: 1 1 1 1 1 0 1 0 1 0 0 1 0 1 1 1
answer
FA97
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Explain why a programmer would prefer to see the contents of the locations displayed as hexadecimal rather than binary, when debugging his program that reads the key presses.
answer
1) easier to identify values 2) easier to spot errors
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