1 /* 2 * Copyright (c) 1988 University of Utah. 3 * Copyright (c) 1990 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the Systems Programming Group of the University of Utah Computer 8 * Science Department. 9 * 10 * %sccs.include.redist.c% 11 * 12 * from: Utah $Hdr: cdvar.h 1.1 90/07/09$ 13 * 14 * @(#)cdvar.h 7.2 (Berkeley) 11/04/90 15 */ 16 17 #define NCDISKS 8 /* max # of component disks */ 18 19 /* 20 * A concatenated disk is described at config time by this structure. 21 */ 22 struct cddevice { 23 int cd_unit; /* logical unit of this cd */ 24 int cd_interleave; /* interleave (DEV_BSIZE blocks) */ 25 int cd_flags; /* misc. information */ 26 int cd_dk; /* disk number */ 27 dev_t cd_dev[NCDISKS]; /* component devices */ 28 }; 29 30 /* cd_flags */ 31 #define CDF_SWAP 0x01 /* interleave should be dmmax */ 32 #define CDF_UNIFORM 0x02 /* use LCD of sizes for uniform interleave */ 33 34 /* 35 * Component info table. 36 * Describes a single component of a concatenated disk. 37 */ 38 struct cdcinfo { 39 dev_t ci_dev; /* devno */ 40 size_t ci_size; /* size */ 41 }; 42 43 /* 44 * Interleave description table. 45 * Computed at boot time to speed irregular-interleave lookups. 46 * The idea is that we interleave in "groups". First we interleave 47 * evenly over all component disks up to the size of the smallest 48 * component (the first group), then we interleave evenly over all 49 * remaining disks up to the size of the next-smallest (second group), 50 * and so on. 51 * 52 * Each table entry describes the interleave characteristics of one 53 * of these groups. For example if a concatenated disk consisted of 54 * three components of 5, 3, and 7 DEV_BSIZE blocks interleaved at 55 * DEV_BSIZE (1), the table would have three entries: 56 * 57 * ndisk startblk startoff dev 58 * 3 0 0 0, 1, 2 59 * 2 9 3 0, 2 60 * 1 13 5 2 61 * 0 - - - 62 * 63 * which says that the first nine blocks (0-8) are interleaved over 64 * 3 disks (0, 1, 2) starting at block offset 0 on any component disk, 65 * the next 4 blocks (9-12) are interleaved over 2 disks (0, 2) starting 66 * at component block 3, and the remaining blocks (13-14) are on disk 67 * 2 starting at offset 5. 68 */ 69 struct cdiinfo { 70 int ii_ndisk; /* # of disks range is interleaved over */ 71 daddr_t ii_startblk; /* starting scaled block # for range */ 72 daddr_t ii_startoff; /* starting component offset (block #) */ 73 char ii_index[NCDISKS];/* ordered list of components in range */ 74 }; 75 76 #ifdef KERNEL 77 extern struct cddevice cddevice[]; 78 #endif 79