aos/devices/fat16_ebpb.dev
Daniel Schwyn 6d444bf552 Main handout
Signed-off-by: Daniel Schwyn <daniel.schwyn@inf.ethz.ch>
2022-03-03 14:57:51 +01:00

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/*
* Copyright (c) 2011, ETH Zurich. All rights reserved.
*
* This file is distributed under the terms in the attached LICENSE file.
* If you do not find this file, copies can be found by writing to:
* ETH Zurich D-INFK, Universitaetstrasse 6, CH-8092 Zurich. Attn: Systems Group.
*/
/*
* fat16_ebpb.dev
*
* DESCRIPTION: FAT16 file system extended BIOS parameter block.
*
*/
device fat16_ebpb msbfirst (addr b) "FAT16 Extended BIOS Parameter Block (EBPB)" {
register drv rw addr(b,0x24) "Drive number" type(uint8);
// In [1], this is described as "current head". The same document says that
// because it is not used as such, Windows NT uses it as follows instead (lsbfirst):
// - bit 0: need disk check
// - bit 1: need surface scan
// [1] http://support.microsoft.com/kb/140418
register rsv rw addr(b,0x25) "Reserved" type(uint8);
// Should be 0x29 to indicate this is an EBPB. 0x28 Also possible, in which
// only the serial number follows.
register ebs rw addr(b,0x26) "Extended boot signature" type(uint8);
register vsn rw addr(b,0x27) "Volume serial number" type(uint32);
regarray vlb rw addr(b,0x2b) [11] "Volume label" type(uint8);
// Should be "FAT16 "
regarray fst rw addr(b,0x36) [8] "File system type, informative" type(uint8);
};