Bits and Bobs Flashcards
Why do we use Hexadecimal?
- Simpler to remember than binary
- Quicker to write
- Less room for error (fewer characters)
- Easy enough to covert
Where do we see Hexadecimal?
On the firmware
Where do we see Binary?
Hardware
Where do we see Python?
Software
What does ASCII Stand for?
American Standard Code for Information Interchange
How many bits does ASCII use?
7 bits usually, to encode 128 characters
Why isn’t 8-bit ASCII still not enough?
It can encode 256 characters, but not enough for characters in other languages
How do bitmap images make up an image?
Each pixel (picture element) is given a binary value which is assigned to a colour
What would happen if you increase the number of bits in a bitmap image?
The more bits, the more colour combinations and the better the image will look
What is Bit/Colour Depth?
The number of colour combinations/amount of colours that can be seen
How to calculate image size?
Colour Depth x Resolution (Width x Height)
How many bits does UNICODE use?
16 bits, 136,755 characters
If you use more bits per sample of audio…
It means that there are more options for the height of the wave (increases sample RESOLUTION), meaning that it can be more accurately measured when converting analogue sound to digital. However, it does increase the file size of the image
What is sample rate measured in?
Hertz (Hz)
So in sample rate, what does 1Hz mean?
1 Sample per second
What is another word for Sample Rate?
Frequency
What does the frequency affect in audio?
It affects the level of detail in the digital representation
How to measure the file size for sound?
Sample resolution x Sample rate x Seconds
How to calculate the image size?
Width x Height (Pixels) - Resolution
What does lossy compression in sound mean?
- Permanently removes some data in order to compress
- Then creates a file with the remaining data and uses algorithms to guess lost data
- The uncompressed data will not be the same as the original, Quality will be removed from the upper and lower frequencies
Lossy Compression in an Image?
- Some data is permanently removed
- Bit Depth is lowered (Similarly coloured pixels will be made the same colour)
- Smaller file size, but loss of quality
Lossless Compression?
- No data is permanently removed
- Just finds a better way of saving storage, by grouping repeated data together in Run Length Encoding
Huffman trees?
- Analyses the frequency at which characters in a text are used
- Characters are placed in a binary tree, where the most frequently used are placed near the top
- It is a representation of an algorithm that compresses data without losing it
What does the Operating System manage?
- Manages how programs use RAM
- Manages Peripherals
- Manages Applications
- Provides Security
- CPU Management
Examples of OS?
Windows, IOS
RAM?
- Can be read from and written to
- Fast Access
- Contains things rnnn
ROM?
- Data that needs to be permanently held in memory
- (BIOS)
When is virtual memory used?
When RAM is filled up, it is uploaded to into secondary storage (Virtual Memory), but the access will be smm slowerrrrr
What affects CPU speed?
- Number of Cores
- Clock Speed
- Cache Size
Embedded Systems?
- Has a single microprocessor
- Carries out very specific tasks
- Bespoke operating system
- No Secondary Storage
- Program held in ROM
- RAM is used to accept user input
