Hardware and communication Flashcards
Cache
Cache is a small sized type of volatile computer memory that provides high-speed data access to a processor and stores frequently/recently used programs and data.
Parallelisation
Parallelisation is technique used to break down large tasks into smaller sub-task to be executed simultaneously on multiple processors or cores
Control unit
coordinates all activities of the CPU
Clock
synchronises related components by generating pulses at a constant rate
ALU
performs arithmetic and logical operations on data (calculations)
Program counter
holds the address of the next instruction to be executed
MAR
holds the address of the memory location from which data or an instruction is to be fetched or to which data is to be written
MDA
used to temporarily store the data which is read from or written to memory
CIR
holds the current instruction being executed
Fetch process
the address of the next instruction is copied from PC to MAR and is then sent through the address bus to RAM. The instruction/data is copied to the MDR and the PC in incremented.
Decode process
the contents of MDR are copied into the CIR and the instruction/data is decoded
Execute process
the instruction is carried out, if it is calculation or logical operation the ALU will process the instruction, the results are stored in the accumulator.
Magnetic storage
Magnetic storage devices store data using magnetic fields which include magnetic tapes, floppy disks and hard drives with magnetic storage.
Advantages: it is one of the cheapest forms of storage and the capacity is very large
Disadvantages: access times can be slow because they are very delicate.
Optical storage
Optical storage devices store data using markers which can be read and written by a laser, it is the best option for music, films and games.
Advantages: it is quite cheap to make and is very lightweight, portable and resilient.
Disadvantages: it tends to have slower access times than most modern magnetic and solid-state hard drives.
Solid state drives
SSD stores data directly onto the silicon microchips electrically rather than magnetically which includes USB, SD cards and portable hard drives.
Advantages: no moving parts so it is much more durable than magnetic hard drives which makes it great for mobile devices and tablets, the access times on SSD drives are a lot faster.
Disadvantages: storage is a lot more expensive than the magnetic and optical alternatives. SSD can only be
written to a limited number of times, they have a limited lifespan.
