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WJEC Computer Science A-level

Hi, so I just finished writing my as level unit 1 exam for computer science and it went pretty well, it was actually surprisingly easy. But on the last question on Manitissa and Exponent. We were basically asked to represent the smallest positive (denary value) with a 5 bit normalised manitissa and a 3 bit exponent, then again for a 4 bit mantissa and 4 bit exponent??

I got 0.0625 and 0.125, can anyone tell me if it's right or wrong??
Reply 1
I got 0.5 for both answers as the 1 in the mantissa has to be to the right hand side of the most significant bit(?)
0.1000 000 -> 0.5 * 2^0 = 0.5
0.100 0000 -> 0.5 * 2^0 = 0.5
Not sure if it is right though :smile:
Reply 2
Original post by OnyxKitten
I got 0.5 for both answers as the 1 in the mantissa has to be to the right hand side of the most significant bit(?)
0.1000 000 -> 0.5 * 2^0 = 0.5
0.100 0000 -> 0.5 * 2^0 = 0.5
Not sure if it is right though :smile:


No yeah you're definetly right. That's what I wrote at first but then I thought that it wasn't normalised and changed it. I'm really hoping it does not carry a lot of marks but I got the rest. The exam was pretty simple to be fair. How did you find yours?
Reply 3
Original post by iamour
No yeah you're definetly right. That's what I wrote at first but then I thought that it wasn't normalised and changed it. I'm really hoping it does not carry a lot of marks but I got the rest. The exam was pretty simple to be fair. How did you find yours?


I found the exam pretty simple too. The advanced info did not lie! The only questions that I struggled with was the compression algorithms (our teacher didn’t cover it), and also boolean algebra. For the last question, I wrote down 2 ranges, one assuming a signed exponent, and one assuming an unsigned exponent just to be safe.
Reply 4
Original post by OnyxKitten
I found the exam pretty simple too. The advanced info did not lie! The only questions that I struggled with was the compression algorithms (our teacher didn’t cover it), and also boolean algebra. For the last question, I wrote down 2 ranges, one assuming a signed exponent, and one assuming an unsigned exponent just to be safe.


How was your unit 2 exam and how was your entity relationship diagram looking like?
Reply 5
Original post by iamour
How was your unit 2 exam and how was your entity relationship diagram looking like?

The unit 2 exam wasn’t too bad and much nicer than I thought (didn’t have to write your own algorithm!). For section B I just copied and pasted most of the program the exam board gave us because I can’t code :smile:
my diagram looked like this:
Trips —= Bookings =— Customers
Reply 6
Original post by OnyxKitten
The unit 2 exam wasn’t too bad and much nicer than I thought (didn’t have to write your own algorithm!). For section B I just copied and pasted most of the program the exam board gave us because I can’t code :smile:
my diagram looked like this:
Trips —= Bookings =— Customers


Awn then I might not get full marks in that question cause I did a many to many relationship diagram between trips and passengers(trips=------=Passengers). I had no idea bookings was even in the question. Luckily I can code pretty well so that aspect was covered lol.
Reply 7
Original post by iamour
Hi, so I just finished writing my as level unit 1 exam for computer science and it went pretty well, it was actually surprisingly easy. But on the last question on Manitissa and Exponent. We were basically asked to represent the smallest positive (denary value) with a 5 bit normalised manitissa and a 3 bit exponent, then again for a 4 bit mantissa and 4 bit exponent??

I got 0.0625 and 0.125, can anyone tell me if it's right or wrong??

were there any topics that stood out in the Unit 1 Paper?
Reply 8
Original post by alrobo
were there any topics that stood out in the Unit 1 Paper?

Hi, if I recall correctly the the highest marking topics apart from the QER (mantissa and exponent) were Computer Networking, Hardwares and Algorithms
Reply 9
Original post by OnyxKitten
Hi, if I recall correctly the the highest marking topics apart from the QER (mantissa and exponent) were Computer Networking, Hardwares and Algorithms

Thank you very much

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