OCR A2 Computing F453 Official Thread 22/06/2016 Exam Discussion

I didn't sit F452 yesterday but it might be worth emailing OCR if you feel there were any problems. I emailed them last year about that 'FreeMeals' variable error and they responded with a pretty lengthy letter that did mention complaints are taken into account during the awarding process (ie setting grade boundaries).

whats there email?

I've gotten this back from them....
....


Dear Mohamed

OCR AssessmentsThank you for your emails earlier today.We have a formal procedure for dealing with all such feedback. We are progressing the issues you have raised through that route and we will be in contact with you again shortly.

Yours sincerely
Customer Service Team

I've gotten this back from them....
....


Dear Mohamed

OCR AssessmentsThank you for your emails earlier today.We have a formal procedure for dealing with all such feedback. We are progressing the issues you have raised through that route and we will be in contact with you again shortly.

Yours sincerely
Customer Service Team

Has anyone seen any questions on MFQ(Multi-level feedback queues) in past papers?

It's one of the scheduling algorithms(3.1.2)


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Never heard of it either. Is it from one of them funny textbooks? Some are too detailed and go into greater detail than the specification requires.

OCR grade boundaries were really low last year. You could lose approximately 40 marks and still get an A.
Btw, what did you get for the question where you had to calculate the size of the file? It was in question 1,

It was 67 for an A last year... I got 66

I have a question in relation to RISC & CISC. Here is my understanding of the terms, roughly:

RISC- Relatively small instruction set, complete given task in 1 clock cycle, each instruction performs a relatively simple operation. 1 CISC instruction = many RISC instructions

CISC - 100's variable format instructions - many include low-level operations to complete a single instruction. There are a wide variety of addressing modes which can include array processing instructions. Complex & can take dozens of clock cycles to complete. More than 1 register sets may be used.


However, there are some inconsistencies in the mark schemes which I have attached and I am a bit confused. Thoughts?

2011-06-F453: 3) b) i) State 3 features of CISC architecture & ii) Disadvantage of CISC compared to RISC, other than cost

2010-01-F453: 3) b) i) Complete the table & ii) Compare the number of machine cycles used by RISC & CISC to complete a single instruction.

Just a prime example of OCR's inadequacies. If a question comes up on it this year, I'm going to stick with the fact RISC singular instructions can be executed in a single cycle, but in order to perform tasks, may need to be joined together. However, one CISC instruction may perform a full task but can take multiple cycles to do so. I think the mark scheme messed up on that one...

To be safe, if the question did come up, it might be best we email OCR with those screenshots to confirm if either would be accepted given they clearly don't even know what's right!

Just a prime example of OCR's inadequacies. If a question comes up on it this year, I'm going to stick with the fact RISC singular instructions can be executed in a single cycle, but in order to perform tasks, may need to be joined together. However, one CISC instruction may perform a full task but can take multiple cycles to do so. I think the mark scheme messed up on that one...

To be safe, if the question did come up, it might be best we email OCR with those screenshots to confirm if either would be accepted given they clearly don't even know what's right!

Yeah I also get confused on those questions I think each "instruction" takes a single cycle in each processor, however a "task" may be made of multiple instructions in RISC. OCR seems to use the terms interchangeably (stupid I know).