OCR GCE A LEVEL 2022 COMPUTER SCIENCE MARKSCHEMES H446-1 PAPER 1-H446/01: Computer systems

Mark Scheme June 2022 MARKING INSTRUCTIONS PREPARATION FOR MARKING SCORIS 1. Make sure that you have accessed and completed the relevant training packages for on-screen marking: RM assessor Online Training; OCR Essential Guide to Marking. 2. Make sure that you have read and understood the mark scheme and the question paper for this unit. These are posted on the RM Cambridge Assessment Support Portal 3. Log-in to RM Assessor and mark the required number of practice responses (“scripts”) and the number of required standardisation responses. YOU MUST MARK 5 PRACTICE AND 10 STANDARDISATION RESPONSES BEFORE YOU CAN BE APPROVED TO MARK LIVE SCRIPTS. MARKING 1. Mark strictly to the mark scheme. 2. Marks awarded must relate directly to the marking criteria. 3. The schedule of dates is very important. It is essential that you meet the 50% and 100% deadlines. If you experience problems, you must contact your Team Leader (Supervisor) without delay. 1. If you are in any doubt about applying the mark scheme, consult your Team Leader by telephone or the RM messaging system, or by email. 2. Crossed Out Responses Where a candidate has crossed out a response and provided a clear alternative then the crossed out response is not marked. Where no alternative response has been provided, examiners may give candidates the benefit of the doubt and mark the crossed out response where legible. Rubric Error Responses – Optional Questions Where candidates have a choice of question across a whole paper or a whole section and have provided more answers than required, then all responses are marked and the highest mark allowable within the rubric is given. Enter a mark for each question answered into RM assessor, which will select the highest mark from those awarded. (The underlying assumption is that the candidate has penalised themselves by attempting more questions than necessary in the time allowed.) Contradictory Responses H446/01 Mark Scheme June 2022 When a candidate provides contradictory responses, then no mark should be awarded, even if one of the answers is correct. Short Answer Questions (requiring only a list by way of a response, usually worth only one mark per response) Where candidates are required to provide a set number of short answer responses then only the set number of responses should be marked. The response space should be marked from left to right on each line and then line by line until the required number of responses have been considered. The remaining responses should not then be marked. Examiners will have to apply judgement as to whether a ‘second response’ on a line is a development of the ‘first response’, rather than a separate, discrete response. (The underlying assumption is that the candidate is attempting to hedge their bets and therefore getting undue benefit rather than engaging with the question and giving the most relevant/correct responses.) Short Answer Questions (requiring a more developed response, worth two or more marks) If the candidates are required to provide a description of, say, three items or factors and four items or factors are provided, then mark on a similar basis – that is downwards (as it is unlikely in this situation that a candidate will provide more than one response in each section of the response space.) Longer Answer Questions (requiring a developed response) Where candidates have provided two (or more) responses to a medium or high tariff question which only required a single (developed) response and not crossed out the first response, then only the first response should be marked. Examiners will need to apply professional judgement as to whether the second (or a subsequent) response is a ‘new start’ or simply a poorly expressed continuation of the first response. 3. Always check the pages (and additional objects if present) at the end of the response in case any answers have been continued there. If the candidate has continued an answer there then add a tick to confirm that the work has been seen. 7. Award No Response (NR) if: • there is nothing written in the answer space Award Zero ‘0’ if: • anything is written in the answer space and is not worthy of credit (this includes text and symbols). Team Leaders must confirm the correct use of the NR button with their markers before live marking commences and should check this when reviewing scripts. 8. The RM comments box is used by your team leader to explain the marking of the practice responses. Please refer to these comments when checking your practice responses. Do not use the comments box for any other reason. If you have any questions or comments for your team leader, use the phone, the RM messaging system, or e-mail. 9. Assistant Examiners will send a brief report on the performance of candidates to their Team Leader (Supervisor) via email by the end of the marking period. The report should contain notes on particular strengths displayed as well as common errors or weaknesses. Constructive criticism of the question paper/mark scheme is also appreciated. H446/01 Mark Scheme June 2022 10. For answers marked by levels of response: a. To determine the level – start at the highest level and work down until you reach the level that matches the answer b. To determine the mark within the level, consider the following: Descriptor Award mark On the borderline of this level and the one below At bottom of level Just enough achievement on balance for this level Above bottom and either below middle or at middle of level (depending on number of marks available) Meets the criteria but with some slight inconsistency Above middle and either below top of level or at middle of level (depending on number of marks available) Consistently meets the criteria for this level At top of level H446/01 Mark Scheme June 2022 Annotation Meaning Omission mark Benefit of the doubt Subordinate clause / consequential error Incorrect point Expansion of a point Follow through Not answered question No benefit of doubt given Point being made Repeat Correct point Too vague H446/01 Mark Scheme June 2022 Zero (big) Blank Page – this annotation must be used on all blank pages within an answer booklet (structured or unstructured) and on each page of an additional object where there is no candidate response. Level 1 Level 2 Level 3 11. H446/01 Mark Scheme June 2022 12. Subject Specific Marking Instructions Question Answer Mark Guidance 1 (a) (i) ● Both data and instructions share the same memory ● Instructions and Data stored in same format ● A single set of buses / same bus for instructions & data (to connect CPU to Memory and I/O) ● Has a (single) control unit ● Has an ALU. ● Has ways to input and output. ● Has access to storage, ● Works sequentially through instructions // follows Fetch-execute cycle ● (Special) registers within CPU ● Based on stored program concept 2 (ii) ● Separate memory for data and instructions / Multiple memory units ● Different (sets of) buses one for instructions & one for data/ instructions and data can be accessed concurrently. 1 (b) ● Higher/faster clock speed ● More cores//dual/quad/etc core ● More cache memory. 2 Answers must refer to an improvement (more/higher/faster) not just “change the clock speed” Allow discussions of level 1/level 2 cache sizes for one mark. Accept valid features of CPUs that would improve performance e.g. Use of: Pipelining Simultaneous Multithreading Do not accept RISC/CISC. (c) (i) ● 10 ● 60 ● 200 3 1 mark per number