CSC 240 Personal Computing for Programmers

Week 1 Presentation on PC Hardware Architecture

Basic Hardware Components

• Motherboard - Main component board.  Houses the CPU, RAM, BIOS, CMOS, bus and expansion slots, drive controllers, and communication ports.
• Power Supply - Connects to the motherboard to supply power to the motherboard and all internal components like floppy & hard disk drives.  The power supply typically provides AC power.  This is what the power plug is connected to inside the computer. 
• I/O card - Sometimes incorporated directly into the circuitry of the motherboard.  Provides Input/Output circuitry & ports to connect serial communications devices (modems, etc) and parallel communication devices (printers, etc).
• Video Card - Card that controlls the display on the monitor.   Typically has its own set of video memory chips called video ram.
• Case - The protective case that all the components of the PC are contained within.
• Monitor - The device that allows images to be displayed to the user.
• RAM - Random Access Memory.  Main memory of the PC.   Capacity typically measured in megabytes (MB - millions of bytes).
• Floppy Drive - A disk drive for a removeable 3.5" disk that allows data to be stored on it.  Max capacity, typically 1.44 MB.
• Hard Drive - Also called Hard Disk or Fixed Disk (because it is located inside the computer and typically NOT removeable).  Provides permanent data storage.  Capacity typically measured in gigabytes (GB - billions of bytes).
• CD-ROM drive - A Read-Only drive that reads data from a compact disk.  Typical capacity, abuot 650 MB.  Beacuse of is trelatively large capacity, it is a favored storage & delivery vehicle for applications that typically need a large amount of space like multimedia, games, etc.
• Modem - Stands for MOdulator/DEModulator.  Allows for serial communications between 2 computers over normal phone lines.  The sending entitiy modulates digital data into analog signals and sends it to the receiving entity.   The receiving entity reverses the process to complete the receiving of the communications process.

Power On Self Test

1. Clear left-over data from CPU's internal memory registers.  Resets program counter to address of the next instruction that needs processing.
2. CPU uses address to find and invoke ROM BIOS boot program, which in turn invokes a series of system checks (POST's).  The CPU fiorst checks itself and the POST program against preset settings.
3. BUS is checked to make sure its functioning.
4. System timer is checked.
5. Memory test on video card.
6. RAM test - CPU writes to each byte and reads what was written.
7. Keyboard test.
8. Disk Drives checked.
9. Results compared to presets (CMOS).
10. BIOS incorporated from other peripherals.

Now, after all that, the Operating System can be loaded....