I/O Interfaces & Buses

Which describes hot plugging, supported by USB and some PCI Express setups?

  1. AA function that automatically cuts power when a device gets hot
  2. BDevices can be connected and disconnected with power on, and the OS recognizes or detaches them automatically
  3. CA function that always reboots the computer when a device is plugged in
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Answer: B. Devices can be connected and disconnected with power on, and the OS recognizes or detaches them automatically

Interfaces that support hot plugging protect devices during connection and removal with power on, using contact sequencing and current limiting, and the OS discovers new devices and loads drivers. Besides USB, it is used with PCI Express when swapping server SSDs, with SATA and others. Telling the OS before removal so that pending writes are completed is important for protecting data.

  • A. That is a different, thermal protection function.
  • B. Correct. No reboot is needed.
  • C. Hot plugging means no reboot is needed.
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More I/O Interfaces & Buses questions

  1. Which bus from Arm's AMBA specifications is widely used to connect blocks such as CPUs, memory controllers and peripherals inside an SoC?
  2. What is a characteristic of the AXI bus?
  3. In the VALID/READY handshake used on each AXI channel, when is data transferred?
  4. What is the advantage of burst transfers in AXI?
  5. In AXI, what is the advantage of issuing the next read request without waiting for the previous one's response (having multiple outstanding requests)?