Overview
This lecture explains the function and types of computer buses on a motherboard, highlighting PCI and PCI Express buses and how expansion cards are installed and connected.
Computer Bus Basics
- A computer bus is a pathway that connects motherboard components for data transfer.
- Buses connect critical components like the CPU, memory slots, and expansion slots.
- Buses enable the addition of expansion cards to increase the system's functionality.
- Physical traces on the motherboard represent these buses.
PCI Bus
- PCI (Peripheral Component Interconnect) is an older bus standard introduced in 1994.
- Available in 32-bit and 64-bit versions, each with parallel communication.
- 32-bit PCI uses 32 parallel lines; 64-bit PCI uses 64 parallel lines for data transfer.
- Expansion cards have connector slots and keyways that match the bus type and power requirements.
- Installing a PCI card involves aligning keyways and pressing the card firmly into the slot, then securing it to the case.
PCI Express (PCIe) Bus
- PCI Express (PCIe) is the modern standard, using serial communication instead of parallel.
- PCIe "lanes" allow data transfer; more lanes (x1, x4, x8) equal higher throughput.
- PCIe slots and cards have different keyway positions and slot lengths compared to PCI.
- PCIe cards may have a locking mechanism that must be released when removing the card.
Key Terms & Definitions
- Bus — Communication pathway connecting motherboard components.
- PCI (Peripheral Component Interconnect) — An older, parallel bus standard for expansion cards.
- PCI Express (PCIe) — Modern, serial bus with scalable throughput via lanes.
- Lane — A single serial data path in PCI Express; multiple lanes increase bandwidth.
- Keyway — A slot or notch ensuring correct card insertion and power compatibility.
Action Items / Next Steps
- Review your motherboard to identify PCI and PCIe slots and note their physical differences.
- Practice safely installing and removing expansion cards, paying attention to keyways and locking mechanisms.