Motherboard

The motherboard is the "body"^{[citation needed]} of the computer. Components directly attached to the motherboard include:

• The central processing unit (CPU) performs most of the calculations which enable a computer to function, and is sometimes referred to as the "brain" of the computer. It is usually cooled by a heat sink and fan.
• The chipset mediates communication between the CPU and the other components of the system, including main memory.
• RAM Stores all running processes (applications) and the current running OS. RAM Stands for Random Access Memory
• The BIOS includes boot firmware and power management. The Basic Input Output System tasks are handled by operating system drivers.
• Internal Buses connect the CPU to various internal components and to expansion cards for graphics and sound.
  • Current
    • The northbridge memory controller, for RAM and PCI Express
      • PCI Express, for graphics cards
    • PCI, for other expansion cards
    • SATA, for disk drives
  • Obsolete
    • ATA (superseded by SATA)
    • AGP (superseded by PCI Express)
    • VLB VESA Local Bus (superseded by AGP)
    • ISA (expansion card slot format obsolete in PCs, but still used in industrial computers)
• External Bus Controllers support ports for external peripherals. These ports may be controlled directly by the southbridge I/O controller or based on expansion cards attached to the motherboard through the PCI bus.
  • USB
  • FireWire
  • eSATA