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

2. Introduction to Computer Science
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Introduction to Computer Science

3. 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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Introduction to Computer Science

4. Computer Hardware - I/O devices
The computer system’s 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 system’s 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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Introduction to Computer Science

5. 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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Introduction to Computer Science

6. 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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Introduction to Computer Science

7. Computer Hardware – Processor (CPU)
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Introduction to Computer Science

8. 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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Introduction to Computer Science

9. 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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Introduction to Computer Science

10. Introduction to Computer Science
CPU
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11. Introduction to Computer Science
Main Memory
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Introduction to Computer Science

12. Introduction to Computer Science
Mother Board
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Introduction to Computer Science

13. Introduction to Computer Science
Printed Circuit Board
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Introduction to Computer Science

14. Introduction to Computer Science
Expansion Slots
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Introduction to Computer Science

15. Introduction to Computer Science
Disk Drive
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Introduction to Computer Science

16. Introduction to Computer Science
Case
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Introduction to Computer Science

17. Introduction to Computer Science
Power Supply
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Introduction to Computer Science