BVSS 2019 P1 Solution

Marking Scheme 1. A company uses spreadsheet software. Match each description to the correct spreadsheet function. [4] Description Returns number rounded up to an exact multiple of significance. Returns the future value of a loan given the interest rate, number of periods and the present value. Returns the number of non-empty cells in the given range references. Returns the interest payment in the specified period for a loan of the present value with an interest rate over the number of periods. Function Ceiling Counta Count Floor FV IPMT PPMT PV Round

2 Q2 Qn Answer 2(a) 1010 1011 (binary) =1*27 + 1*25+ 1*23 + 1*21 + 1*20 = 1*128 + 1*32 + 1*8 + 1*2 + 1*1 = 171 (denary) 2(b) AE3 (hexadecimal) = 10*162 + 14*161+ 3*160 = 278710 (denary) Alternative solution: AE3 = 1010 1110 00112 = 211 +29 +27 +26 +25 +21 +20 = 278710 2(c) 1m for working, 1m for correct answer divisor number remainder (decimal) remainder (hexadecimal) 16 123587 16 7724 3 3 16 482 12 C 16 30 2 2 16 1 14 E 16 0 1 1 123587 (denary) = 1E2C3 (hexadecimal) 2(d) 1m each (max 2m) • RGB colour code • Memory dumps • Network addresses • Unicode • URL encoding

3 Qn 3 Marking Scheme / Answer A(n) address bus transfers required memory location from processor to memory. It is uni-directional. The Control unit is part of the processor that follows instructions and decides when data should be stored, received or transmitted by different parts of the computer. Arithmetic logic unit (ALU): processes data by performing basic mathematical and logical operations Secondary storage is where large amounts of data are stored, such as in a hard disk or hard drive. RAM is where data and instructions are stored temporarily so that they can be quickly accessed by the processor when needed. Qn 4 Marking Scheme / Answer (a) Odd parity: Received byte Corrupted Not corrupted Reason 10001101 ✔ The sum of the number of “1” bit is 4 (even). It should be odd. 01101101 ✔ The sum of the number of “1” bit is 5 (odd) and is correct. (b) Re-reading the byte that was sent or request for that the byte to be resent.

4 Qn 5 Marking Scheme / Answer (a) 1m each (max 2m) • Spyware is a malware which is usually hidden and it secretly collects personal information about its users • Spyware transmits this “stolen” information to attackers without the users’ knowledge. 1m each (max 2m) • Trojan horse is a malware that pretends to be a harmless file or useful application • Once a Trojan horse is run, it does something harmful such as giving intruders unauthorised access to the computer (b) Two factor authentication is the type of authentication that uses evidence from both something the user knows and something the user owns. Example: 1m each (max 1m) user name, password, hand phone, security token, biometric access

5 Qn 6 Marking Scheme / Answer (a) 1m each (max 1m) A interpreter is a code translator program that