1.2 Memory and Storage Flashcards
Why do computers need primary storage?
To allow fast access to the Cpu
What is RAM?
Random access memory-Temporary volatile storage of instructions and data
What is ROM?
Read only memory-Non volatile memory that contains information for a computers start up
What is the difference between Ram and Rom?
Ram is volatile-Rom is non volatile
Ram is read and write-Rom is read only
Ram is temporary-Rom is permenant
What is Virtual memory and why is it needed?
When Ram is full instructions are transferred to the Virtual memory
What is the need for secondary storage?
Rom is read only and Ram is volatile so secondary storage is needed for:
The storage for data when the computer is switched off
Semi perminant storage of data
Back up of data files
What is optical storage and the advantages and disadvantages?
Optical storage is CD,DVD and Blu Ray
It is very cheap,lightweight and portable however is slow to access and has low storage.
What is magnetic storage and the advantages and disadvantages?
Magnetic storage is Hard disk drives and magnetic tape
It has a high storage,cheap and quick access however it has moving parts and are not durable
What is solid state and the advantages and disadvantages?
Solid State is SSDs and USBs
It have good storage,quick access,robust and reliable however it is expensive
State all the units of data storage in order and their values
Unit Symbol Binary Value
Bit b 0 or 1
nibble 4 bits
Byte B 8 bits
Kilobyte KB 1000 B
Megabyte MB 1000 KB
Gigabyte GB 1000 MB
Terabyte TB 1000 GB
Petabyte PB 1000 TB
How do you calculate sound file size?
sample rate x duration x bit depth
How do you calculate text file size?
bits per character x number per characters
How do you calculate image file size?
colour depth x image height x image width
What is 0100 1000 in Denary?
72
What is 201 in Binary?
1100 1000
What is 0110 1011 in Hex?
6B
What is D5 in Denary?
213
What happens when you do a binary shipt 2 places to the left?
You times by 4
When you move 0110 2 places to the right it becomes 0001 Why?
There is an overflow error
What are the different character sets?
ASCII and Unicode
If A is represented as 0001 in Ascii what is B?
0010
What is the difference between ASCII and extended ASCII?
ASCII is an eariler version with 7 bits however extended ASCII is a later version which is 8 bits and codes for other languages aswell
How are images represented and what affects the file size?
Images are represented through bitmaps made up of different coloured pixels and the more pixels or colours the larger the file size.
What is metadata?
Meta data is data abut data eg and image meta data would be the height, width or time taken
How is sound represented and stored in digital form?
Sound is sampled and the sample rate is measured and converted into Binary
How does the sample rate,duration and bit depth effect the sound quality and file size?
The higher the Bit depth and sample rate the better the quality howvere the longer the duration.higher the sample rate and higher the bit depth the bigger the file size.
What is Lossy compression?
Compression that can be used on images or sound to significantly decrease the amount of storage needed however some of the data is lost
What is Lossless compression?
Compression that is used on documents to slightly reduce the file size as it doesnt lose any data but encodes it differently
What is the difference between Lossy and Lossless compression?
Lossy permenantly losses data however in lossless it can be changed back to its original form. Lossy is a lot more effient than lossless
