Please enable JavaScript.

Coggle requires JavaScript to display documents.

Processing ( ( , , ), Hardware (Central Processing Unit (Made up of two…

- - - - Control unit
        
        Directs the entire computer system
        
        Selects and retrieves instructions from storage in sequence, interprets them and starts the required operation
      - Arithmetic Logic Unit (ALU)
        
        Carries out all arithmetical and logical calculations
        
        Arithmetical calculations are calculations like addition, subtraction, multiplication and division
        
        Logical calculations are true or false answers
        
        Contains register
        
        Register is a temporary storage area for small amounts of data that are needed to process
  - - - ROM
        
        Holds data and instructions that are fixed at the time of production and cant be changed by the user or computer
        
        It is permanent memory that only lets the data be read
        
        Instructions in the ROM are called firmware as they are between the software and hardware
        
        Data inside of the ROM is protected from being damaged or changed
        
        Instructions that allow the computer to communicate with input and output devices are called ROM BIOS
        
        Programmable ROM chips let data and instructions to be entered once and after that cant be reprogrammed
        
        The difference between Programmable ROM and ROM is that Programmable ROM is manufactured as blank memory while ROM is firmware which is entered during the manufacturing process
        
        Erasable programmable ROM chips are allowed to be erased and reprogrammed by the manufacturer
        
        If exposed to ultraviolet light, the memory clears
        
        Cache
        
        Temporary storage area used to store frequently requested data and instructions
        
        Two types of caching
        
        Cache memory
        
        High speed memory located between the CPU and RAM
        
        Improves performance by using Static RAM and reducing the need for CPU to access the slower Dynamic RAM
        
        Disk Cache
        
        Stores the most recent data from the hard disk in RAM
        
        Improves the computers performance as accessing data from RAM is a thousand times faster than accessing a disk
        
        Allows the computer to operate faster, the bigger the cache the faster the computer will operate
        
        The effectiveness of the cache depends on the number of times the CPU finds the data in the cache, this is called the hit rate
        
        RAM
        
        Random access memory (RAM) holds data and instructions temporarily
        
        It is volatile memory and the data in RAM can be accessed randomly
        
        There are two main types of RAM
        
        Dynamic RAM
        
        This is memory that has to be constantly refreshed
        
        Its content has to be updated a thousand times a second because the capacitors used to store data can quickly lose their electrical charge
        
        A type of Dynamic RAM that has synchronized with the CPU is called the Synchronous Dynamic RAM and is faster than a normal Dynamic RAM
        
        Inexpensive and small
        
        Static RAM
        
        This memory doesn't have to be updated
        
        Static RAM has a faster access time compared to Dynamic RAM
        
        Expensive
- - - - The arithmetic logic unit does the operation on the data
        
        The control unit puts the results of this operation into either the memory or register
- - - - This requires a special software that has to be able to recognize how to divide the problem up and bring the end results back together