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WJEC A2 Computing CG3 - Tuesday 23rd June 2015 [Exam Discussion Thread]

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Reply 140
Original post by Tyche
Thank you! Yeah I guess that's what it means. I'm trying to piece stuff together because we just focused on coursework for the majority of the year and our teachers rushed through theory. Sorry I couldn't help.

I found an online copy of "theteacher" whilst looking for what it may mean, it contains notes based on the wjec spec: http://theteacher99.host22.com/


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Reply 141
Reply 142
Original post by Tyche
Thank you!


No worries! Only exception I take to that is that "translation" implies the use of a compiler OR an interpreter surely? Because an error whilst the program is compiled is surely a translation error just as much as a program being executed using an interpreter finding an error?

It should really be "linkage error, compiler error, execution error" imo.

Do I make sense? 😂


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Original post by Enrico2285
This is my last exam, just going through the revision guide that I've got and past papers


I think "Langages, visual, 4th gen, OOP, packages" may arise again, If it did I suspect that it would catch loads of people out.. In all fairness I think it's harder than most of the spec


Yeah i would say if something from the past is going to come up it will probably be languages, which would be horrible, just need to practise it i suppose, I'm not a fan of the languages questions, nor the sequential, indexed sequential and random, hate indexed sequential!!!!

I guess we will see come Tuesday!
I think another thing to point out with the exam, especially for the last longer mark question, is that you should have a go at everything they ask you too, even if you completely blag it

I say this because in mark schemes i see "Max 6 marks if 1 area attempted, Max 8 marks if 2 areas attempted" or similar, so have a go at everything and your marks can't get capped, i would guess :smile: obviously i don't know
Reply 145
Original post by jamietopp21
Yeah i would say if something from the past is going to come up it will probably be languages, which would be horrible, just need to practise it i suppose, I'm not a fan of the languages questions, nor the sequential, indexed sequential and random, hate indexed sequential!!!!

I guess we will see come Tuesday!


I've been revising off of past mark schemes but I just hope they don't ask for obscure parts of the spec :/


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Original post by CD223
I've been revising off of past mark schemes but I just hope they don't ask for obscure parts of the spec :/


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Yeah thats exactly what I've been doing but the problem is I'm pretty sure they're changing the spec next year (or so i was told) so i think they'll try and test things that haven't really come up before, which is annoying as I've been doing really well in past papers aha!
Reply 147
Original post by jamietopp21
Yeah thats exactly what I've been doing but the problem is I'm pretty sure they're changing the spec next year (or so i was told) so i think they'll try and test things that haven't really come up before, which is annoying as I've been doing really well in past papers aha!


You think so? There's been so many similar questions each year though! I feel like they have to come up again! Is this the last year?


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Original post by CD223
You think so? There's been so many similar questions each year though! I feel like they have to come up again! Is this the last year?


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I was told by my teacher that they were changing the spec next year so, but i do agree they seem to have similar things each year, i just hope they do the same.

Things I've noticed that almost always come up are (in my experience) :

serial/parallel transmission
Why are network protocols necessary
recursive algorithms (Fibonacci or factorial)
Logical operations, truth tables, etc
Backus Naur Form/syntax diagram
Creating a 3rd normal form solution
Pseudo code algorithm
Reply 149
Pseudo code is always a killer, since the mark scheme is very specific
Original post by Enrico2285
Pseudo code is always a killer, since the mark scheme is very specific


Yeah however I've noticed on the mark scheme it does say that efficiency/elegance doesn't gain or lose marks - and it usually says "other solutions are possible" so as long as the code would work you should be okay, normally you get marks for 1) inputs 2) calculations (usually mean/ finding out max or min) 3) loops 4) If statements 5) outputs, so its fairly easy to at least pick up a few marks!
Reply 151
Original post by jamietopp21
Yeah however I've noticed on the mark scheme it does say that efficiency/elegance doesn't gain or lose marks - and it usually says "other solutions are possible" so as long as the code would work you should be okay, normally you get marks for 1) inputs 2) calculations (usually mean/ finding out max or min) 3) loops 4) If statements 5) outputs, so its fairly easy to at least pick up a few marks!


Backus Naur definition is always a beauty of a question.


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Original post by CD223
Backus Naur definition is always a beauty of a question.


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Yes! however i always seem to define too many things, i was doing a past paper and it said money could be represented as an integer, with a decimal point and 2 digits afterwards, and if it was in brackets it was a negative number... so

12.66, 145.00, (23.00) ... being some examples

the mark scheme had this:

<digit> ::= 0|1|....|8|9
<integer> ::= <digit> | <digit> <integer>

<money> ::= <integer>.<digit><digit> | ( <integer>.<digit><digit> )

or something similar, but i also defined

<fullstop> ::= .
<bracket> ::= ( | )

can someone tell me whether i would lose marks and what i don't need to define in these kinds of questions, id hate to miss out on marks for missing out something i needed to define
Reply 153
Original post by jamietopp21
Yes! however i always seem to define too many things, i was doing a past paper and it said money could be represented as an integer, with a decimal point and 2 digits afterwards, and if it was in brackets it was a negative number... so

12.66, 145.00, (23.00) ... being some examples

the mark scheme had this:

<digit> ::= 0|1|....|8|9
<integer> ::= <digit> | <digit> <integer>

<money> ::= <integer>.<digit><digit> | ( <integer>.<digit><digit> )

or something similar, but i also defined

<fullstop> ::= .
<bracket> ::= ( | )

can someone tell me whether i would lose marks and what i don't need to define in these kinds of questions, id hate to miss out on marks for missing out something i needed to define


You won't lose marks at all. Don't worry :smile:


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I'm confused why is it on some papers for some years they call it multiprogramming and other years it's multitasking? Are they two different things or the same?
Reply 155
Original post by Amberfernandes
I'm confused why is it on some papers for some years they call it multiprogramming and other years it's multitasking? Are they two different things or the same?


Multi programming is essentially the same as multitasking. If you look at the mark scheme they refer to the same concepts. It's frustrating, I agree.

"both multiprogramming and multitasking operating systems are (CPU) time sharing systems. However, while in multiprogramming (older OSs) one program as a whole keeps running until it blocks, in multitasking (modern OSs) time sharing is best manifested because each running process takes only a fair quantum of the CPU time."


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Reply 156
"Describe the principles of high level scheduling: processor allocation, allocation of devices and the significance of job priorities".

What comes under this point of the spec?

Also, what are the techniques to manage overflow?


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Original post by CD223
"Describe the principles of high level scheduling: processor allocation, allocation of devices and the significance of job priorities".

What comes under this point of the spec?

Also, what are the techniques to manage overflow?


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"High level scheduling is when a computer system chooses which jobs, tasks or requests to process"

The different scheduling processes I've seen are FIFO (first in first out i.e. no priority), round robin (where all processes get a time slice, all processes are started but still no priority) and Fixed Priority Scheduling (where each process is given a priority based on a) how many recourses it will use b) how important it is to process (e.g. power failure) and c) how long it has been waiting to process

Overflow in regards to overflow/underflow, or overflow in regards to random files?
(edited 8 years ago)
Reply 158
Original post by jamietopp21
"High level scheduling is when a computer system chooses which jobs, tasks or requests to process"

The different scheduling processes I've seen are FIFO (first in first out i.e. no priority), round robin (where all processes get a time slice, all processes are started but still no priority) and Fixed Priority Scheduling (where each process is given a priority based on a) how many recourses it will use b) how important it is to process (e.g. power failure) and c) how long it has been waiting to process

Overflow in regards to overflow/underflow, or overflow in regards to random files?


Oh great thanks! I'd learnt of the types of processor (round robin) but wasn't sure if that's what the bulletpoint meant!

Overflow with regards to number systems I believe.

Overflow management in random files would just be to use a new hashing algorithm or a larger file right?


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Original post by CD223
Oh great thanks! I'd learnt of the types of processor (round robin) but wasn't sure if that's what the bulletpoint meant!

Overflow with regards to number systems I believe.

Overflow management in random files would just be to use a new hashing algorithm or a larger file right?


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Yeah those are the ways processes can be scheduled!

And to manage overflow you should allocate more storage space to store a number, to manage underflow you should round or truncate the number being stored! :smile:

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