You are Here: Home

# AQA AS Computing - COMP2 - June 3rd 2015 - Exam Discussion Thread watch

1. Hey, we have lots of COMP1 discussions but I couldn't find a COMP2 thread (if there is then I don't it's been posted on in weeks). We have 9 days to go! If anyone has any questions then feel free to ask and I'll try to answer!

- AQA Wikibooks
- COMP2 Notes (Blogspot)

Question Predictions:
- Previous Hardware And Possible Hardware - Principle Of Operation

Machine Level Architecture:
- Simplifying Boolean Equations

Computer Systems:
- Pros And Cons Of Compilers And Interpreters
- List Of Hardware
- Previous Hardware And Possible Hardware - Principle Of Operation

The Internet:
- Web Page Design
- DNS And Internet Registry

Legal And Ethical Issues:
- Law Notes
2. Let's start this schnitzel off with getting people's prediction for questions:
3. (Original post by Normal.Person)
Let's start this schnitzel off with getting people's prediction for questions:
COMP2? It could be anything. I guess they will ask us how a hardware device works (for 4 or 6 marks), as they almost always do. I have no idea.
4. Anyone got any idea of the Hardware this year?
5. I can't get my head around simplifying boolean expressions, is there an easy way to do it? They have come up in the last two papers so AQA love them
6. (Original post by arjunlotay)
Anyone got any idea of the Hardware this year?
What do you mean?

(Original post by ItsIzzy)
I can't get my head around simplifying boolean expressions, is there an easy way to do it? They have come up in the last two papers so AQA love them
People who have done Electronics A-Level will find this so easy. One thing you can do is say the equation to yourself.
For example:
B . (A + A^)
Would be:
(A OR NOT A) AND B
And when you see that you should logically think, A OR NOT A is always true. So you are left with B AND TRUE. Then if you think logically about that the answer will just be B. Not sure if that made any sense to you, but it is a good way to do it.

-----

There are also a load of small rules you can remember:
A . A^ = 0
A + A^ = 1
A . 0 = 0
A . 1 = A
A + 0 = A
A + 1 = 1

So for the equation you used above you could replace the A + A^ with 1, leaving you with:
B . 1, but then you can replace that with just B using those rules.

----

Also remember De Morgans theorem. Make a bar and change the sign, or break the bar and change the sign. That's a simple way to remember it.

-----

Hopefully that made sense, if not just ask. Keep practicing and you will get it eventually.
7. Can someone explain to me the pros and cons of interpreters and compilers? Thanks!
8. (Original post by CheetahCurtis)
What do you mean?

People who have done Electronics A-Level will find this so easy. One thing you can do is say the equation to yourself.
For example:
B . (A + A^)
Would be:
(A OR NOT A) AND B
And when you see that you should logically think, A OR NOT A is always true. So you are left with B AND TRUE. Then if you think logically about that the answer will just be B. Not sure if that made any sense to you, but it is a good way to do it.

-----

There are also a load of small rules you can remember:
A . A^ = 0
A + A^ = 1
A . 0 = 0
A . 1 = A
A + 0 = A
A + 1 = 1

So for the equation you used above you could replace the A + A^ with 1, leaving you with:
B . 1, but then you can replace that with just B using those rules.

----

Also remember De Morgans theorem. Make a bar and change the sign, or break the bar and change the sign. That's a simple way to remember it.

-----

Hopefully that made sense, if not just ask. Keep practicing and you will get it eventually.
Thank you! That was very useful
9. (Original post by jamesgates1)
Can someone explain to me the pros and cons of interpreters and compilers? Thanks!
No offence, but did you even bother to look for an answer yourself. The answer can be found in a textbook or on the internet pretty quickly, and it's not complicated.

Pro's of using a compiler for a program:
- No need to distribute the source code (and the user wont need a compiler)
- Program runs faster than an interpreted one

Pro's of using an interpreter for a program:
- Program can be executed immediately (no waiting for it to compile)
- Helpful for finding errors when building the program, instead of the program crashing
10. (Original post by CheetahCurtis)
No offence, but did you even bother to look for an answer yourself. The answer can be found in a textbook or on the internet pretty quickly, and it's not complicated.

Pro's of using a compiler for a program:
- No need to distribute the source code (and the user wont need a compiler)
- Program runs faster than an interpreted one

Pro's of using an interpreter for a program:
- Program can be executed immediately (no waiting for it to compile)
- Helpful for finding errors when building the program, instead of the program crashing
Thanks. I had looked at wikibooks first and also do not prefer the book.
11. (Original post by jamesgates1)
Thanks. I had looked at wikibooks first and also do not prefer the book.
There are even more points on the wikibook
http://en.wikibooks.org/wiki/A-level...ram_translator
12. Any idea for which hardware device they will ask us the principles of operation of ? I assume they wont be repeating previous papers but I suppose that they could.
13. (Original post by ItsIzzy)
I can't get my head around simplifying boolean expressions, is there an easy way to do it? They have come up in the last two papers so AQA love them
I take a very math-y approach to it.

E.g. B.A^ + B.A, You see a "common factor" B so take out B leaving (A^ + A) whereby one can easily guess that if a is 0, then 1 OR 0 gives 1 and if A is 1, 0 OR 1 gives 1 hence B.1 = B
(Obviously that's one of many examples, like expanding a factorised polynomial)

EDIT (cuz I got bored): if it's (A^ + B) . (A.B^)^ = (De Morganise (A^ + B) . (A^ + B)
Multiply out brackets: A^.A^ + B.A^ + A^.B + B.B = A^ + A^.B + B = A^.(1 + B) + B = A^ + B
14. (Original post by Normal.Person)
I take a very math-y approach to it.

E.g. B.A^ + B.A, You see a "common factor" B so take out B leaving (A^ + A) whereby one can easily guess that if a is 0, then 1 OR 0 gives 1 and if A is 1, 0 OR 1 gives 1 hence B.1 = B
(Obviously that's one of many examples, like expanding a factorised polynomial)
I'd probably do similar for that question.

And if you get confused, you can always draw a truth table for the question and your answer to compare the results.

If anyone doesn't understand simplifying then it might be worth looking at karnaugh maps:
http://www.ee.surrey.ac.uk/Projects/.../karrules.html
But you aren't expected to know them in the exam and if the question asks for your working then you probably wont get the marks, but it always gives you the right answer. For the simple equations in AS computing, you don't really need it.
15. (Original post by CheetahCurtis)
I'd probably do similar for that question.

And if you get confused, you can always draw a truth table for the question and your answer to compare the results.
Make sure you write some bull sheiz for the working out as some questions reject truth tables as working out
16. I think you guys should expect either a Fetch-Execute Cycle (long marker) or a comparison between the Internet, Intranet and WWW (long marker).
17. Also, generations of programming languages hasn't come up in a while. Make sure you revise that

They will ask like a 1 marker on logic errors. Why? (I'm not even sure if it's called a logic error, don't judge).
The following:

Spoiler:
Show

Yes, I've a mac whilst programming in C#, don't judge :P
19. (Original post by Normal.Person)

They will ask like a 1 marker on logic errors. Why? (I'm not even sure if it's called a logic error, don't judge).
The following:

Spoiler:
Show

Yes, I've a mac whilst programming in C#, don't judge :P
Mac + C# =
And this is the COMP2 thread, you want COMP1
20. Does anyone have any good revision materials? (other than wikibooks)

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: June 10, 2015
Today on TSR

### Edexcel C4 Maths Unofficial Markscheme

Find out how you've done here

### 1,788

students online now

Exam discussions

### Find your exam discussion here

Poll
Useful resources

Can you help? Study Help unanswered threadsStudy Help rules and posting guidelines

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE