SYSTEM BOARD
PC -or- XT Bus:
8088 8 Bit data pathAT (ISA) Bus: First used on the 80286 processor. Has a 16-bit data path. Still runs at 8 MHz.
ATX Motherboard: 90-degree rotation of expansion and microprocessor slots. New layout providing more space for full-length add-in cards. New layout requiring fewer cables. New layout providing better cooling and ventilation. Lower manufacturing costs.
MCA
: Micro Channel Architecture. 16 or 32 Bit data path. Designed by IBM, had no backward compatibility, and because of its licensing requirements was short lived.EISA Bus
: (Extended Industry Standard Architecture) Better than MCA because of 32 Bit path and that it was backward compatible.VESA Local Bus
: (VL) Similar to EISA but has a wider bus (64 Bit).PCI:
Bus mastering. Can communicate directly to CPU.PCMCIA:
(Personal Computer Memory Card Industry Standard)Three types: Type I: 3.5mm Type II: 5mm Type III: 10.5mm
SYSTEM BOARD COMPONENTS
Identify:
AT / ATX
CPU
- What type and clock speed, Clock speeds are measured in Megahertz, which means millions of cycles per second. The external clock speed is the speed at which the processor accesses information outside itself in external cache memory or system RAM. The internal clock speed is the speed at which the processor obtains information within its own confines-in its registers or in its internal cache memory.Clock Speed-Although the activities of a microprocessor are considered quite simple and repetitive, the processor's strength is in the speed at which it performs these routine operations.
The system clock provides a steady tempo at which other devices operate in essence, this is the "heartbeat" of the microcomputer.
Timing throughout the system must be synchronized. For each clock tick, the system pulses a request through the microprocessor and this creates the corresponding cycle of the system. A cycle can represent a single request or answer from the microprocessor.
Ticks of the clock are counted in millions. There are millions of clock ticks or cycles per second, measured in Megahertz (MHz). The heart of the clock is a thin slice of quartz crystal. When electric pulse that travels by wire to every component on the system. Components use pulses to coordinate messages they send to each other. The steady clock beat guarantees that when one component sends a signal, another is timed and ready to receive it.
The clock determines how many times a microprocessor changes its state (due to Voltage changes) per second; this sets the processor's throughput rate. Clock speed determines how many program instructions can be completed within a period of time. The higher the clock speed, the faster the computer.
Adapter Slots
- ISA 8 and 16 Bit PCI AGPRAM
(30 or 72 Pin)Battery
ATX
(IDE, SERIAL Port, Parallel Port)Microprocessor
Supporting Chipset Circuitry
System Bus (External Bus)
Keyboard Controller and Connector
Power Connectors
Math Coprocessor (If Installed)
Video Controller ? (Not all boards)
Mouse Port
Integrated Disk Controller
SYSTEM BOARD PERFORMANCE ISSUES
Speed:
Factors processors clock speed, the size of its internal and external data busses, and the processors design. Intel is currently releasing dual-speed processors, which operate at different internal and external clock speeds. The overall speed of the system board is also affected by the bus speed.Configuration:
This refers to the way in which the system board is configured, and how easy it is to change board configurations.Memory:
Memory includes both the amounts that can be installed on the system board and what is addressable by the microprocessor. Types of memory and how they are related are covered later in this course.Bus Type:
Support for ISA or EISA and the different local bus platforms, PCI or VESA local-Bus, should be a consideration in purchasing a motherboard.Support Circuitry:
This refers to integrated "add-ons" such as video and communication ports.Software Support:
Different system boards support different variations in operating system and application software.