Sensors
Data sent to and from another device twice. Sender compares 2 sets of data, if the sets of data are different, an error has occurred.
What is echo check?
CD/DVD/DVDRAM (all optical) , blu ray disks (optical media), flash memory/memory stick/SD XD cards (solid state devices) and removable HDDs (magnetic media
What is off-line storage?
our way of telling a computer what to do, how to do it, and when to do it
What is a program?
used in many control operations involving sensors and ADC/DACs. Electromagnetic device eg. motor that outputs result of sensor operation
Additional value sent at the end of a data block. When block is about to be transmitted, additional value calculated and then transmitted. Value recalculated at the end to make sure they match. If they don't match, an error has occurred.
What is checksum?
1. Volatile/tempory
2. Stores data, programs or parts of OS currently in use
3. Can be written to or read form
4. Can be DRAM or SRAM
DRAM - needs to be constantly refreshed to retain the data, uses millions of transistors and capacitors.
SRAM - doesn't need to be constantly refreshed to retain its data, uses flip flop
What is RAM?
1. Solid state technology
2. Connect through a USB port
3. Small and lightweight so ideal for transferring files and photos between different computers
What is Flash Memory/Memory Sticks?
- more reliable and robust
- lighter and thinner
- consume less power and run much cooler
- no need for SSDs to get up to speed and faster data access rate
What advantages do SSDs hold over HDDs?
1. Blue light
2. Uses this to read-write the data
3. Wave length of blue light is 405nm (shorter than red) they can store considerably more data.
4. Single polycarbonate disk (unlike DVDs which use a sandwich of two polycarbonate disks)
5. Therefore blu-ray disks don't suffer from birefringence (light refraction into two separate beams which can cause reading errors)
What are Blu-ray disks?