2018 SRSS P1 Answers

1 Serangoon Secondary Computing Sec 4E 2018 Preliminary Exams (Answers) Q1) Description Function Q2) a) = 18110 b) F16 = 1510 = 11112 816 = 810 = 10002 = 1111 1000 c) Denary Quotient Remainder 250 ÷ 16 15 1010 = A16 15 ÷ 16 0 1510 = F16 = FA16 128 64 32 16 8 4 2 1 1 0 1 1 0 1 0 1 Returns number rounded up to a given multiple MODE SMALL ROUND Returns the most repeated number in a set of numbers Use to retrieve the nth lowest number from a set of numbers CEILING

2 Q3) Cause of error Description (any one point) Prevention (any one point) Integrity of data (any one point) Authentication • process of verifying the identity of a user • password • security tokens • Two-factor authentication / OTP • biometrics • someone other than the user can have access to personal data and • perform unauthorised transactions without the user knowledge Access control • Permissions to control ability to view or make changes to the contents of folder or files • Set permissions to members only based on types of user / group of users • Privacy settings • Firewall • Encryption • Data not meant for certain users to view / modify can be compromised accidentally Privacy policy • Rules and practices that govern how the data can be accessed • Implement a Data Protection Act • Read and understand the privacy policy of the organisation providing the service • Unauthorised access can also occur indirectly due to the actions of third-party users or services.

3 Q4) Q5) A bus is used to transfer bits of data between the different components found on the motherboard One such component is the ROM which stores the instructions to the start-up the computer. Q6) a) Device: - Network Interface Card (NIC) Function: - Provides the hardware interface to .. - enable the transfer of data between a device and a network b) Device: - Bridge / Switch Function - Device that constructs a single network by connecting two similar networks together - Has more intelligence, send packets only to intended recipients thus avoiding less data congestion (data travelling at any point in the network c) Device: - Router / Getway Function: - Device that forwards paclets between separate networks - Chose the best route to transfer to destination network - Uses IP address to transfer data Statement Interpreter Compiler takes one statement at a time and executes it ü generate an error report at the end of translation of the whole program ü stops the translation process as soon as the first error is encountered ü slow speed of execution of program loops ü translates the entire program in one go ü

4 Q7) a) Any three from • IP address – Used by Internet Protocol to o identify the network and host address of the devices o Logical address (may change / not fixed) o IPv4 address take the form of a 4 bytes or group (IPv4 32-bits) • MAC address – Media Access Control to o Identify the computer in the local network o Phy