## Storage Device Driver Reference

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### Identifying Extended Device Drivers and Capabilities

If the physical device driver is an extended device driver, it recognizes the GET DRIVER CAPABILITIES command. This command returns a characteristics bit field, which describes functional capabilities of the device driver, and an entry point vector, which includes the extended strategy routine and several device driver control routines. If the device driver does not recognize the command or does not respond appropriately, the kernel and all client FSD assume the physical device driver supports only standard OS/2 requests and restricts its behavior appropriately.