Topic 2.1.1

Topic 2.1.1

1. CU: Control Unit

   • Two functions of the CU
     • Handles the loading of new commands into the CPU (and the decoding of these commands)
     • Directs the data flow and the operation of the ALU

2. MAR

   • Contians RAM address of the instructions the CPU wants next

3. MDR

   • Holds data that will be written to the RAM or that was written from the RAM
   • The MAR gives the adress the data of the MDR will be read from or written to

4. Busses

   • Connecting wires, connecting CPU to other devices.
     • Busses carry instructions to/from components

5. Topic 2.1.2

   • In the exam, memory= RAM
   • ROM: Read Only Memory - Non-Volatile
     • Unlike RAM, it doesn't lose its components if power is lost
     • Stores BIOS
       • Small program that allows the computer to know what to do, to find the OS to boot the computer after
   • Cache
     • A small, high-speed memory inside the CPU that holds frequently used data
       • This is in order for the CPU almost never have to access the MUCH slower RAM
   • Topic 2.1.4 - Machine instruction cycle
     • • The basic operation of a computer, is called the fetch-execute cycle
         • Computer fetches instructions, then executes them
           • This is repeatedly done from when the computer is booted up to when its shut down
         • Fetching the instructions
           • The CPU fetches them from the RAM and temporary stores them in registers
           • Decoding
             • Once the instruction has been fetched, CPU needs to understand the instruction, in order to action it.
             • Executing the instruction
     • 2.1.5 - Persistent Storage
       • 2.1.6 Main Functions of an OS
         • Provides an user interface
         • Does memory managment
         • Does peripheral managment
           • External Hardware devices (mouses, keyboard, etc.) are controlled through drivers
             • Drivers are a software program which allows hardware devices to be used by the OS
               • Drivers act as translators between the devices and the computer system
         • Allows multi-tasking
         • Provides security

6. Generals

   • 8 bits= 1 byte
   • Denary = Base 10 (0,1,2,3,4,5,6,7,8,9)
   • Hexadecimal : 16 Digits
     • 0123456789ABCDEFG
   • AND = Multiplication, osea: 0X0=0
     • 1X1=1
   • OR = SI HAY 1, A HUEVO ES 1
   • XOR = SI HAY 2 IGUALES, ES 0

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