Information Technology Reference
In-Depth Information
2
Supporting USB
Many mass-storage devices store files that PCs or other computers must
access. To make files available to any PC or other USB host, a device can use
either of these approaches:
• Include a USB device controller and support for USB's mass-storage
class. The files can be stored in any media. To access the files from a USB
host, attach the device to a USB port on the host.
• Include a USB host controller and a mass-storage driver. The device can
then store files on the same USB drives that PCs and other USB hosts
can access. To access the files from another USB host, remove the drive
from the device and attach the drive to the other host.
An additional option that doesn't require USB support on the device is to
store files in flash-memory cards. To access a card's contents from a PC,
insert the card in a card reader/writer device either built into the PC or
attached via USB. (You can also use flash-memory cards as the storage media
in a device that has a USB interface.)
A USB device interface is a popular choice for mass-storage devices because
it's inexpensive to implement and convenient to use. Every recent PC has
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