[jtanna]

(Original post by exam2k10)
Just out of interest, "How does a Universal Turing Machine's output differ to a standard Turing Machine?"

(Original post by joenye)
I would very much like to know this also.

There is no difference, as a UTM executes the TM's instructions faithfully. The only real difference that could be said is that it executes a little slower, but that's it

[PreciseUrination]

What do we have to know for the Simulation topic?

Do we have to be aware of the full process involved in creating a simulation of a problem?

[joenye]

(Original post by jtanna)
There is no difference, as a UTM executes the TM's instructions faithfully. The only real difference that could be said is that it executes a little slower, but that's it

Thank you for the clarification, I didn't think there was any difference in output either.

For anyone interested, a UTM takes a longer amount of time to complete its operation because it is an interpreter, so has to fetch each instruction (from the description <M> of any arbitrary turing machine M) before it can execute it.

An interpreter simply works its way through a set of instructions, fetching the next instruction and then executing it.

With that ramble out the way, I want to wish good luck upon everyone, I hope it goes well for you all!

[exe]

how would the output of a UTM be different if it "executes the instructions faithfully"?

[sax100]

can someone quickly explain the mod function to me...
e.g 33 mod 5 what does it = ?

i believe its 6 but it dont know.

[ldvico]

(Original post by sax100)
can someone quickly explain the mod function to me...
e.g 33 mod 5 what does it = ?

i believe its 6 but it dont know.

it's the remainder. say you had 33 sweets between 5 people, each person would get 6 sweets each. There's 3 left that you can't share equally between the 5 people. so 33 mod 5 is 3

[Jarred]

I know it's sort of late now but does anyone have any good resources explaining hashing. It's not in the book and I haven't been taught it. Do I actually need to know how to run the algorithm, explain it or just know when it will be used? I'm scared one of the big QoL questions will be "Explain hashing, BOOM 6 marks down the crapper"

Also, as for graph/tree traversal diagrams, I've not been taught those for a very, very long time and I don't seem to recall seeing them in the book, again I must ask; how much do I need to know on them?

Any help will be appreciated. I'm not looking forward to this exam, think it will go horribly wrong but I hope the right stuff comes up, if it's like past papers it'll be ok, need to get an A in this. Problem is that with such a new spec, I can't be certain what I need to know if y'all catch my drift? Our paper could contain something the past papers didn't. I'm used to maths, where the specification dates back to 2004, I can practise pretty much everything with that but not with computing.

[FredrickTrott]

(Original post by Edwin Okli)
I'm just checking out the WJEC specification right now, it seems to actually be quite a big larger than our COMP3 specification, with some things from our AS modules in there.

On another note. I kind of made a revision guide (from the textbook and other notes). I'll attach it here and people can tell me if there are any mistakes or content that needs to be added.

(Too large to be attached.)

Not sure if i'm wrong (Probably am) But on the Real numbers section (Pg32) of your Revision Guide, you have a worked example for converting -23.375, and you give the answer as 1.01000101 (Mantissa) 000111 (Exponent), i get the same Mantissa, but my Exponent to be 5 (000101). If i am wrong, can someone explain why please.

Thanks

[BalletDystopia]

Ok right we don't have to know about system development do we? Analysis and testing? e.g Acceptance testing. I don't see it in the spec I have but there's q's on the aqa exam style q's sheet.

[ldvico]

(Original post by Jarred)
I know it's sort of late now but does anyone have any good resources explaining hashing. It's not in the book and I haven't been taught it. Do I actually need to know how to run the algorithm, explain it or just know when it will be used? I'm scared one of the big QoL questions will be "Explain hashing, BOOM 6 marks down the crapper"

Also, as for graph/tree traversal diagrams, I've not been taught those for a very, very long time and I don't seem to recall seeing them in the book, again I must ask; how much do I need to know on them?

Any help will be appreciated. I'm not looking forward to this exam, think it will go horribly wrong but I hope the right stuff comes up, if it's like past papers it'll be ok, need to get an A in this. Problem is that with such a new spec, I can't be certain what I need to know if y'all catch my drift? Our paper could contain something the past papers didn't. I'm used to maths, where the specification dates back to 2004, I can practise pretty much everything with that but not with computing.

Go to Page 6 of this thread, scroll to ngnav's post and click the link in the quote. Then find the hashing section in the word document

[ldvico]

(Original post by BalletDystopia)
Ok right we don't have to know about system development do we? Analysis and testing? e.g Acceptance testing. I don't see it in the spec I have but there's q's on the aqa exam style q's sheet.

That's coursework...haha xD

[Jarred]

(Original post by ldvico)
Go to Page 6 of this thread, scroll to ngnav's post and click the link in the quote. Then find the hashing section in the word document

Thankyou

[Amirrryy]

is open hashing and closed hashing part of the syllabus cos the syllabus is very vague on this topic..stupid aqa :/

[SecondHand]

(Original post by Amirrryy)
is open hashing and closed hashing part of the syllabus cos the syllabus is very vague on this topic..stupid aqa :/

No idea lol, but open hashing is where you find the next free memory location and closed hashing is where you used a linked list.

[fluteflute]

(Original post by Jarred)
I know it's sort of late now but does anyone have any good resources explaining hashing. It's not in the book and I haven't been taught it. Do I actually need to know how to run the algorithm, explain it or just know when it will be used? I'm scared one of the big QoL questions will be "Explain hashing, BOOM 6 marks down the crapper"

Also, as for graph/tree traversal diagrams, I've not been taught those for a very, very long time and I don't seem to recall seeing them in the book, again I must ask; how much do I need to know on them?

AQA has published on their website what is effectively the missing textbook chapters.

Go to http://web.aqa.org.uk/qual/gce/ict/c..._materials.php -> Teacher Resource Bank -> Unit Support Materials

[BalletDystopia]

And yet another question that will probably help everyone. Abstraction by generalization and by representation. I really don't understand the book on these 2 parts. Could someone explain it simply like i'm 5 please?

[Edwin Okli]

(Original post by FredrickTrott)
Not sure if i'm wrong (Probably am) But on the Real numbers section (Pg32) of your Revision Guide, you have a worked example for converting -23.375, and you give the answer as 1.01000101 (Mantissa) 000111 (Exponent), i get the same Mantissa, but my Exponent to be 5 (000101). If i am wrong, can someone explain why please.

Thanks

You're right. Thanks for pointing it out.

[FredrickTrott]

(Original post by Amirrryy)
is open hashing and closed hashing part of the syllabus cos the syllabus is very vague on this topic..stupid aqa :/

Yes it is.

This is copied right out of Edwins Revision Guide


Open hashing - a method in which a collision is resolved by storing the record in the "next available" location.

Closed hashing - all other locations in the table are closed off therefore a pointer column is added and a linked list of records with the same hash key is created.

These are the most succinct definitions i have seen so far.

[ldvico]

(Original post by Edwin Okli)
You're right. Thanks for pointing it out.

Oh, and on page 28 for binary searching, I think it should have said:

"Cow" < "Dave" so we reject items 1-3.

[Amirrryy]

(Original post by FredrickTrott)
Yes it is.

This is copied right out of Edwins Revision Guide


Open hashing - a method in which a collision is resolved by storing the record in the "next available" location.

Closed hashing - all other locations in the table are closed off therefore a pointer column is added and a linked list of records with the same hash key is created.

These are the most succinct definitions i have seen so far.

yea i know all the definitions for hashing but i mean will they for example give us a table and tell us to hash it using open hashing/closed hashing ? i doubt it i think?