Phase 1.09
Computer Buses & Interconnections
The highways of data: Types, architecture, and communication modes.
A Bus is a communication pathway shared by multiple components.
Types of Buses
- Data Bus: Carries actual data bits (Bidirectional). Width (bits) determines bandwidth.
- Address Bus: Carries the address location (Unidirectional). Width determines Max Addressable Memory ($2^N$).
- Control Bus: Carries timing and command signals (RD, WR, RESET).
Bus Architecture
- System Bus: Connects CPU, Memory, and Chipset. High speed.
- Peripheral Bus: Connects North/Southbridge to I/O slots (PCIe, USB).
- Expansion Bus: Connects additional components (GPU, Network).
Communication Modes
- Parallel: Multiple bits sent at once over multiple wires. High throughput but distance-limited (Crosstalk).
- Serial: One bit sent after another over a single wire. Modern standard (SATA, USB, PCIe) due to higher clock speeds and signal integrity at distances.
Technical Terms Breakdown
Bus Width
The number of bits a bus can transmit simultaneously (e.g., 64-bit).
Bandwidth
The total data transfer rate, calculated as Width × Frequency.
System Bus
The primary backbone bus connecting the CPU to the memory controller.
Daisy Chaining
A wiring scheme where multiple devices are connected in sequence.