1.1. Number systems
A subsection of Computer Science, 2210, through 1. Data representation
Listing 10 of 41 questions
Letters from the alphabet are represented in a computer by the following denary (base 10) values: A = G = 103 I = 105 L = 108 N = 110 The word “A L I G N” is stored as: 97 108 105 103 110 Convert each of the five values to binary. The first one has been done for you. Letter Denary value A (97): 0 L (108): I (105): G (103): N (110): An encryption system works by shifting the binary value for a letter one place to the left. “A” then becomes: This binary value is then converted to hexadecimal; the hexadecimal value for “A” will be: C 2 For the two letters “L” and “G”, shift the binary values one place to the left and convert these values into hexadecimal: hexadecimal L: G:
2210_s15_qp_12
THEORY
2015
Paper 1, Variant 2
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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.
2210_s16_qp_11
THEORY
2016
Paper 1, Variant 1
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Convert the following hexadecimal number into 12-bit binary: 4 A F The 2016 Olympic Games will be held in Rio de Janeiro. A timer that counts down to the opening of the Games is shown on a microprocessor-controlled display. The number of hours, minutes and seconds until the Games open are held in three 8-bit registers. The present register values are: 105 hours 32 minutes 20 seconds The timer will count down in seconds. Show the values in each 8-bit register 30 seconds after the time shown above: hours minutes seconds Write the hexadecimal value of the minutes register from part .
2210_s16_qp_12
THEORY
2016
Paper 1, Variant 2
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In the following barcode, each binary number is made up of seven bars. Each bar is black or grey. A black bar is interpreted as a “1” and a grey bar is interpreted as a “0”. Write the binary numbers that would be produced from this barcode: %LQDU\QXPEHU$ %LQDU\QXPEHU% Binary number A: Binary number B: This barcode system uses odd parity. Write the parity bit for each of the binary numbers in part : Parity bit Binary number A: Binary number B:
2210_s16_qp_12
THEORY
2016
Paper 1, Variant 2
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The three binary numbers in the registers A, B and C have been transmitted from one computer to another. Parity bit Register A Register B Register C One binary number has been transmitted incorrectly. This is identified through the use of a parity bit. Identify which register contains the binary number that has been transmitted incorrectly. Explain the reason for your choice. The binary number that has been transmitted incorrectly is in Register Explanation
2210_s18_qp_11
THEORY
2018
Paper 1, Variant 1
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A stopwatch uses six digits to display hours, minutes and seconds. The stopwatch is stopped at: 0 2 3 1 5 8 Hours Minutes Seconds An 8-bit register is used to store each pair of digits. Write the 8-bit binary numbers that are currently stored for the Hours, Minutes and Seconds. Hours Minutes Seconds The stopwatch is started again and then stopped. When the watch is stopped, the 8-bit binary registers show: Hours Minutes Seconds Write the denary values that will now be shown on the stopwatch. Hours Minutes Seconds
2210_s18_qp_12
THEORY
2018
Paper 1, Variant 2
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The three binary numbers in the registers X, Y and Z have been transmitted from one computer to another. Parity bit Register X Register Y Register Z Only one binary number has been transmitted correctly. This is identified through the use of a parity bit. Identify which register contains the binary number that has been transmitted correctly. Explain the reason for your choice. The binary number that has been transmitted correctly is in Register Explanation
2210_s18_qp_12
THEORY
2018
Paper 1, Variant 2
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Questions Discovered
41