Summary
Summary ALL OF COMPUTER SCIENCE NOTES 0478 (everything U NEED TK)
- Course
- Institution
Summary of 22 pages for the course Cambridge at Cambridge (ITS HELPT LOADS)
[Show more]
Seller
Follow
aahilkamran
Content preview
Computer Science Paper 1● Data representation
● Data transmission
● Hardware
● Software
● The internet and its uses
● Automated and Emerging technologies
Data representation
Any information needs to be converted into BINARY
Binary:
- Base 2 number system
- 2 values → 1 (ON) and 0 (OFF)
- Switches
- Logic gates
Denary:
- Base 10 number system
Hexadecimal:
- Base 16 number system
Programmers find hexadecimal more convenient:
❖ 1 hex represents 4 binary digits → more compact
❖ Easier to read, write and copy
❖ Less prone to errors
USES OF HEXADECIMAL (EMIH)
❖ Error codes
❖ MAC address (Media access and control)
❖ IP address (internet protocol)
❖ HTML (hypertext markup language)
,Overflow Error → extra bit → register may have a fixed size → thus extra bit is log
Logical Shift
- Left → x2 1 = x2 2 = x4 3 = x8
- Right → ÷2 1 = ÷2 2 = ÷4 3 = ÷8
- Registers often have a 8 bit limit
- Multiplying can cause bits to be lost
- Losing the most significant bit
Two's Complement
- Used to represent negative numbers
If start digit:
0 = positive
1 = negative
Text
- Every character is represented by binary code
- Character set: collection of characters and symbols that have been defined or recognised by the computer,
each character and symbol has a unique value.
ASCII
UNICODE
ASCII UNICODE
Unique 8 bit binary code Uses 16 to 32 bits
UC, LC, digits and punctuation marks Characters in different languages can be represented
Uses values 0 to 127 Emojis
128 to 256 characters Unicode has 60 thousand to 4 billion characters
1 byte for 1 character 4 bytes for 1 character
Characters used in other language can be represented
Disadvantage for using UNICODE
More bits per character can result in a larger file size and slow processing times when working with text based data
, Sound (is analogue as it varies continuously)
- Analog sound is Captured and recorded using microphone
- The sound wave is sampled at regular time intervals to measure the amplitude
- This gives an approximate representation of sound waves
- Each amplitude has a unique binary value
- The sample rate is set which is the number of samples taken per second
- The sample resolution is set which is the number of bits used for each sample
- Each sample taken is converted to binary
Sampling Resolution (Bit depth)
- Number of bits used to represent sound amplitude in digital sound recording
- Increase sampling resolution
Gives more accurate representation of sound wave
Greater quality
Increase file size
Sample Rate
- The number of sound samples taken per second
1Hz = 1 sample per second
- Increasing sample rate
Gives a more accurate representation
Greater quality
Increase file size
pros and cons of increasing sample rate/resolution
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller aahilkamran. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
76799 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now