Computer Hardware Organization (How does the computer look from inside?)

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Computer Hardware Organization(How does the
computer look from inside?)
CPU
Register file
ALU
PC
System bus
Memory bus
Main memory
I/O bridge
Bus interface
I/O bus
Expansion slots for other devices such as network
adapters
USB controller
Disk controller
Graphics adapter
Mouse
Keyboard
Display
Disk
Executable (machine language) program stored on
disk
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Computer Hardware Buses

• Electrical conduits connecting computer
  components
• Transport bytes of information back and forth
  between components
• Designed to transfer chunks of bytes called words
• The number of bytes in a word (word size) is a
  fundamental system parameter
• For example, Intel Pentium systems have a word
  size of 4 bytes (32 bits)

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Computer Hardware - I/O devices

• The computer systems connection to the external
  world
• Examples, Keyboard(I), mouse(I), Screen(I), disk
  drive (I and O)
• Each I/O device connects to the bus by a
  controller or an adaptor.
• A Controller is a chip set in the device itself,
  or on the systems main board (motherboard)
• An Adaptor is a card that plugs into a slot on
  the motherboard
• Purpose of controller or adaptor is to over see
  the transfer bits back an forth the I/O bus and
  the I/O device.

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Computer Hardware Main Memory(MM)

• MM is a temporary storage device (in what way
  temporary?) and connection to the external world
• Holds both a program and its data which the
  program manipulates while the processor is
  executing the program
• Physically, MM consists of a collection of
  Dynamic Random Access Memory (DRAM) chips.
• Logically, MM is organized as a linear array of
  bytes, each with its own unique address.
• The only operations MM understands is to read
  (transfer bytes from an address to CPU), or to
  write (transfer bytes from the CPU to a given
  address)

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Computer Hardware Processor (CPU)

• The Central Processing Unit (CPU) interprets
  instructions stored in MM
• Among other things contains the following
• Program Counter (PC), a register that contains
  the address the next program instruction.
• Registers, a collection of small storage devices
  both special and general purpose.
• Arithmetic/Logic unit (ALU), computes new data
  and address values (think of it as the calculator
  of the computer)

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Computer Hardware Processor (CPU)
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Computer Hardware CPU Process

• FETCH - Read from MM the instruction (bits) whose
  address is in PC register.
• DECODE - Interpret the bits in the instruction.
• EXECUTE - Perform some simple operation dictated
  by the instruction.
• In parallel, update the address in the PC
  register to the address of the next instruction.

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Computer Hardware CPU Instructions

• Load Copy a word from MM into a register.
• Store Copy a word from a register to a location
  in MM.
• I/O read/write Copy a word between an I/O device
  and a register
• Arithmetic Add, subtract, multiply, divide.
• Logic And, or, not, xor, etc.

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CPU
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Main Memory
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Mother Board
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Printed Circuit Board
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Expansion Slots
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Disk Drive
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Case
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Power Supply