1/* 2 * Copyright (c) 2011, ETH Zurich. All rights reserved. 3 * 4 * This file is distributed under the terms in the attached LICENSE file. 5 * If you do not find this file, copies can be found by writing to: 6 * ETH Zurich D-INFK, Universitaetstrasse 6, CH-8092 Zurich. Attn: Systems Group. 7 */ 8 9/* 10 * fat16_bootsector.dev 11 * 12 * DESCRIPTION: FAT16 file system boot sector. 13 * 14 * This always starts at offset 0xb and is documented as such in Microsoft 15 * documentation [1], so put the first entry at offset 0xb too, allowing the 16 * initialize function to be called with the regular base address. 17 * 18 * [1] http://support.microsoft.com/kb/140418 19 */ 20 21device fat_bpb msbfirst (addr b) "FAT BIOS Parameter Block (BPB)" { 22 23 register bps rw addr(b,0x0b) "Bytes per sector (must be 512, 1024, 2048 or 4096)" type(uint16); 24 25 register spc rw addr(b,0x0d) "Sectors per cluster, must be power of 2" type(uint8); 26 27 register rsvs rw addr(b,0x0e) "Reserved sectors from the start of the volume" type(uint16); 28 29 register fatc rw addr(b,0x10) "Number of FAT copies" type(uint8); 30 31 register rtc rw addr(b,0x11) "Maximum number of root entries" type(uint16); 32 33 register ssc rw addr(b,0x13) "Small sector count, used when volume is smaller than 32 MB" type(uint16); 34 35 register mdes rw addr(b,0x15) "Media descriptor" type(uint8); 36 37 register spf rw addr(b,0x16) "Sectors per FAT" type(uint16); 38 39 register spt rw addr(b,0x18) "Sectors per track" type(uint16); 40 41 register heds rw addr(b,0x1a) "Number of heads" type(uint16); 42 43 register hids rw addr(b,0x1c) "Hidden sectors (preceding volume start)" type(uint32); 44 45 register lsc rw addr(b,0x20) "Large sector count, when volume is larger than 32 MB" type(uint32); 46 47}; 48