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The operating system provides support for SD host controllers that connect directly to the PCI bus. Windows manages these devices with the USB mass storage driver ( usbstor.sys) and the native storage class driver ( disk.sys), as depicted in the following diagram:įor a more complete description of the device stack that Windows creates for a memory card that connects to the USB bus, see Device Object Example for a USB Mass Storage Device. This document explains how the operating system supports the card function extensions to SD technology.Ĭard readers for many early SD storage devices were designed to connect to the USB bus.
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Secure Digital (SD) card technology began with portable, miniature memory cards, but with the release of the Secure Digital I/O (SDIO) specification, the Secure Digital Association (SDA) has broadened the definition of SD technology to include a large variety of card functions, such as Bluetooth devices, video cameras, Wireless LAN devices, and Global Positioning System (GPS) receivers.
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