Answer: D. Portable PCs typically use a technique called shared video memory. Under shared memory, the system uses a portion of its main memory to hold screen information for the display. One of the disadvantages of shared memory is that it takes up memory space that applications would normally use. It also causes the system to show less memory capacity than is installed because a portion has been reserved for use with the video display.

Answer: A. External read/write CD-ROM and DVD drives typically connect to the system through a USB port, a FireWire port, an external SCSI connector, or though a CardBus adapter. With the exception of the SCSI-based version, all these interfaces are hot swappable.

Answer: D. The proper procedure for removing a USB device from the computer begins with clicking the Safely Remove Hardware icon in the systray. Then select the command to stop the operation of the USB device you want to remove. When the operating system prompts you, physically remove the USB device from the system. The Safely Remove Hardware utility is used to notify the operating system in advance of the device removal. Because some devices have write caching enabled, corruption or data loss may occur.