the basics of computer science

the basics of computer science

1. CPU

   • the cpu is the central processing unit
     • what the cpu does is to fetch and execute instructions from the memory
       • the fetch and execute cycle
     • the cpu is more or less the brain of the computer
   • the cpu processes data

2. the fetch and execute cycle

   • basically this cycle we speak of is carried out by the cpu
   • fetching is when the cpu finds out which instruction it needs to carry out. the nstruction comes from the memory
   • the cpu fetches the instruction from the memory and then carries it out.

3. RAM

   • stands for random access memory
   • all contents of the ram is lost when the power is switched off
   • when a program loads, the instructions are loaded unto ram

4. ROM

   • stands for read only memory
   • the rom stores data that will not need to be updated
   • when the power is switched off, the data does not go anywhere

5. ALU

   • stands for arithmetic logic unit
   • this is one part of the CPU
   • this is where all the calculations take place

6. control unit

   • retrived data from the memory and executes the instructions
     • directs the flow of insructions and co-ordinates parts of the cpu

7. different types of memory

   • cloud storage
     • e.g: icloud
     • refers to when data is stored away from the computer
     • and can be accesed at different points over the internet
   • magnetic storage
     • include the actual hard disk that the memory is stored on
   • optical storage
     • e.g: cd's, dvd's etc.
     • are written and read using lasers
   • solid state storage
     • e.g: flash drives and usb's
     • use electronic circuits to store data
   • These are all secondary storage

8. HDD

   • stands for hard disk drive
     • can store large amounts of data

9. flash memory

   • operates in a similar way to ROM
     • uses electronic chips as storage
       • is portable

10. cache memory

    • stores copies of instructions from the ram

11. internal memory

    • provides fast access storage to data that is being used by the cpu

12. controller