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OCR AS Computer science paper 1 5th June 2017

Hey everyone, the computer science exams are coming up next week on Monday and Friday and I see that no other threads have been made for this so I have decided to be the first. What do you predict to come up? do you know anyone who took it last year and if so how did they find it? How's revision going?

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Reply 1

Nada Elhannach

Original post by UsKmekwioz

I think they might ask us to let the user save the file.i am really bad at the programming bit of computer science so im just cramming everything the night before.

Reply 2

GayElf

Lets make an unofficial mark scheme.

1. Topic = Vonneuman / Registers
a)
i) What is a register? [3?]

Spoiler

ii) Name another component of von-neuman architecture [1]

Spoiler

b)
i) State an operation which causes the ACC to change [1]

Spoiler

ii) Describe what the Pc stores [2]

Spoiler

c) State two LMC operations which will cause the PC to change [2]

Spoiler

2. Topic = PC improvements
Some fool has is having poor performance.Suggests how he can make it better? [9]

Spoiler

3. Topic = JavaScript.
a) What do the following lines mean?

var total = "" : [1]

Spoiler

for (var j =0;j<200000;i++) : [2]

Spoiler

total = total + str(j) : [1]

Spoiler

4. Binary / Data representation

1.
a) Convert the following from hex to binary : 0110 1111 [1]

Spoiler

b) Convert -19 to Twos complement [1]

Spoiler

c) -19 in sign and magnitude

Spoiler

d) subtraction question

e) Express 1 + 5/8 as a floating point number with a mantissa of 5 and exponent of 3.

Spoiler

f) A company distributes parcels and takes a picture of them before and after transit.They then use this to compare if any damege has occurred using a digital camera.Explain what type of storage would be best for this flash or magnetic.

Spoiler

6. Topic = Boolean
a) Draw the symbol for an XOR gate [1]

Spoiler

b) Describe the difference between an OR and XOR gate [2]

Spoiler

c) Diagram of (A OR B) OR (C OR D) Complete the truth table [1?]

Spoiler

d) Simplify expression[1?]

Spoiler

7.
a) Descibe the TCP/IP Stack

b) Disadvantage of ASCII over UNICODE

Pseudocode :

array called words = ["word1","word2",etc]
Multipledimensional array called Display[20,4]

Write a program which will display the words onto the fridge

8. Topic = Website accessibility

How can a website developer use techniques to accommodate otherly able and mobile users [9]

Questions Unaccounted for :

Many
Lossless vs lossy compression
pseudocode
entitty diagram between parcel and customers

(edited 6 years ago)

Reply 3

GayElf

Original post by ChicGem6372

Wow, looks like I have got most of the answers wrong already :colondollar:

Post any answers you have.Most questions had more than 1 possible answer.

Reply 4

Waveyalex

6F for the hexadecimal question ?

Reply 5

GayElf

Original post by Waveyalex

6F for the hexadecimal question ?

Yup.Do you remember what question that was? 4?

Reply 6

Waveyalex

Original post by GayElf

Yup.Do you remember what question that was? 4?

Soz i dont still but the other one is also lossy compression and there was one bout flash storage,no moving parts less vulnerable to damage ?

Reply 7

chloebirdy

questions you missed out:
sign and magnitude of -19 (1)
normalisation of 1.628 (3)
entity diagram parcel and customers (2)
lossy vs loseless which is better for pictures of parcel (2)
why is flash memory is better for storing pictures than magnetic tape (1)

Reply 8

GayElf

Original post by chloebirdy

added

Reply 9

Waveyalex

one customer has many parcels right ?

(edited 6 years ago)

Reply 10

UsKmekwioz

Original post by Waveyalex

one customer has many parcels right ?

Many customers have many parcels i said

Reply 11

UsKmekwioz

Original post by Waveyalex

6F for the hexadecimal question ?

I got that

Reply 12

Waveyalex

Original post by UsKmekwioz

Many customers have many parcels i said

1 parcel cant have many customers but 1 customer cant have several parcels ?

Reply 13

UsKmekwioz

Original post by Waveyalex

1 parcel cant have many customers but 1 customer cant have several parcels ?

More than 1 customer can have more than 1 parcel

Reply 14

waveywaver123

Is this old spec or new spec ??

Reply 15

Subspace

Anyone have an idea on what the two pseudocode questions were exactly? (revising for the A-level exams in a few weeks)

Reply 16

GayElf

Original post by waveywaver123

Is this old spec or new spec ??

New Spec

Reply 17

GayElf

Original post by Subspace

Anyone have an idea on what the two pseudocode questions were exactly? (revising for the A-level exams in a few weeks)

One was a 4 marker other a 7.

The 7 marker was something along these lines.This is roughly what was asked.

A fridge can display a message with up to 20 characters per row for 4 rows.Between each word is a space.If a word is too long to be put onto a single line it is put onto the next.

words = ["Remember","to","get","milk","tommorow"]

where words is a queue.The front can be removed by the syntax words.remove() such that :

int temp = words.remove() // temp = "Remember"

The fridge text is controlled by the variable Display[20,4]

Write a procedure to update the fridge text.

Something like that.

Reply 18

Gamer_44

The truth table was 4 marks