## General advice - Be explicit when showing your workings. ## 1 Please write 0s. It costs you nothing. Make sure you draw all the boxes around the groups. ## 2 ### i Good. ### ii Remember that the sign flips. ## 3 ### a Always convert the exponent to denary (it's a free mark). RTQ: it clearly states the mantissa and exponent are written in two's complement (so the MSB is negative). If you got 78.5, it's because you missed this. ### b I would also encourage you to write and annotate your workings explicitly, e.g., $ \begin{align*} \text{Given:}\quad & 00001011\ 0111 \\ & \text{Mantissa} = 0.0001011, \quad \text{Exponent} = 0111_2 = 7_{10} \\[6pt] \text{Shift binary point:}\quad & 0.0001011 \;\to\; 0000.1011 \quad (\text{point moves 3 places right}) \\ & \text{Renormalise to } 0.1011000 \;\Rightarrow\; 01011000 \\[6pt] \text{Adjust exponent:}\quad & 7 - 3 = 4_{10} = 0100_2 \\[6pt] \text{Answer:}\quad & \boxed{\text{Mantissa} = 01011000, \quad \text{Exponent} = 0100} \end{align*} $ This is a bit extra, but it helps to be as explicit as possible in your workings (even if doing so doesn't necessarily gain marks). ## 4 Be careful with your verbs. ## 5 Poor. This question wants specific details of what happens: contents of **registers** get copied to the stack, etc. Answers generally lacked detail (check the mark scheme and update your notes)—including priorities. ## 6 Responses were often vague and skipped over lots of details. This is a 5 mark question which means you should be saying about 5 different things. 'Wrap around' is too vague a description: how does the wrapping around work? Check the mark scheme! ## 7 ### a The formal names for the methods of dealing with collisions that we studied are *chaining* and *linear probing*. Please make sure to use these names when referring to them. ### b RTQ. The question clearly says you should refer to the example—so refer to the example! ## 8 ### a Good. I agree with the examiner comments about precision of language. ### b Good. ### c Good. ### d This question is about the implementation described in question 8. The wording of the question indicates this by saying "A new item needs to be added to **the** linked list". In this implementation, you do not traverse to find 'Null' to check for free space: `freeListPointer` indicates the next free space. Most responses failed to use the implementation given in the question.