Intel Extensible Firmware Interface - Manual (Page 378)

Extensible Firmware Interface Specification
11-18 12/01/02 Version 1.10
Description
The Simple File System protocol provides a minimal interface for file-type access to a device. This
protocol is only supported on some devices.
Devices that support the Simple File System protocol return an EFI_FILE_IO_INTERFACE .
The only function of this interface is to open a handle to the root directory of the file system on the
volume. Once opened, all accesses to the volume are performed through the volume’s file handles,
using the
EFI_FILE protocol. The volume is closed by closing all the open file handles.
The firmware automatically creates handles for any block device that supports the following file
system formats:
• FAT12
• FAT16
• FAT32