1 /* $NetBSD: config.h,v 1.1 1999/03/18 17:18:05 perseant Exp $ */ 2 3 /*- 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)config.h 8.3 (Berkeley) 5/24/95 36 */ 37 38 /* 39 * The first boot and super blocks are given in absolute disk addresses. 40 * The byte-offset forms are preferred, as they don't imply a sector size. 41 */ 42 #define BBSIZE 8192 43 #define SBSIZE 8192 44 45 /* 46 * The following two constants set the default block and fragment sizes. 47 * Both constants must be a power of 2 and meet the following constraints: 48 * MINBSIZE <= DESBLKSIZE <= MAXBSIZE 49 * sectorsize <= DESFRAGSIZE <= DESBLKSIZE 50 * DESBLKSIZE / DESFRAGSIZE <= 8 51 */ 52 #define DFL_FRAGSIZE 1024 53 #define DFL_BLKSIZE 8192 54 55 /* 56 * Cylinder groups may have up to many cylinders. The actual 57 * number used depends upon how much information can be stored 58 * on a single cylinder. The default is to use 16 cylinders 59 * per group. 60 */ 61 #define DESCPG 16 /* desired fs_cpg */ 62 63 /* 64 * MINFREE gives the minimum acceptable percentage of file system 65 * blocks which may be free. If the freelist drops below this level 66 * only the superuser may continue to allocate blocks. This may 67 * be set to 0 if no reserve of free blocks is deemed necessary, 68 * however throughput drops by fifty percent if the file system 69 * is run at between 90% and 100% full; thus the default value of 70 * fs_minfree is 10%. With 10% free space, fragmentation is not a 71 * problem, so we choose to optimize for time. 72 */ 73 #define MINFREE 10 74 #define DEFAULTOPT FS_OPTTIME 75 76 /* 77 * Preference for optimization. 78 */ 79 #define FS_OPTTIME 0 /* minimize allocation time */ 80 #define FS_OPTSPACE 1 /* minimize disk fragmentation */ 81 82 83 /* 84 * ROTDELAY gives the minimum number of milliseconds to initiate 85 * another disk transfer on the same cylinder. It is used in 86 * determining the rotationally optimal layout for disk blocks 87 * within a file; the default of fs_rotdelay is 4ms. 88 */ 89 #define ROTDELAY 4 90 91 /* 92 * MAXCONTIG sets the default for the maximum number of blocks 93 * that may be allocated sequentially. Since UNIX drivers are 94 * not capable of scheduling multi-block transfers, this defaults 95 * to 1 (ie no contiguous blocks are allocated). 96 */ 97 #define MAXCONTIG 1 98 99 /* 100 * MAXBLKPG determines the maximum number of data blocks which are 101 * placed in a single cylinder group. The default is one indirect 102 * block worth of data blocks. 103 */ 104 #define MAXBLKPG(bsize) ((bsize) / sizeof(daddr_t)) 105 106 /* 107 * Each file system has a number of inodes statically allocated. 108 * We allocate one inode slot per NFPI fragments, expecting this 109 * to be far more than we will ever need. 110 */ 111 #define NFPI 4 112 113 /* 114 * For each cylinder we keep track of the availability of blocks at different 115 * rotational positions, so that we can lay out the data to be picked 116 * up with minimum rotational latency. NRPOS is the default number of 117 * rotational positions that we distinguish. With NRPOS of 8 the resolution 118 * of our summary information is 2ms for a typical 3600 rpm drive. 119 */ 120 #define NRPOS 8 /* number distinct rotational positions */ 121 122 /* 123 * The following constants set the default block and segment size for a log 124 * structured file system. Both must be powers of two and the segment size 125 * must be a multiple of the block size. We also set minimum block and segment 126 * sizes. 127 */ 128 #define LFS_MINSEGSIZE (64*1024) 129 #define DFL_LFSSEG (1024 * 1024) 130 #define DFL_LFSSEG_SHIFT 20 131 #define DFL_LFSSEG_MASK 0xFFFFF 132 133 #define LFS_MINBLOCKSIZE 512 134 #define DFL_LFSBLOCK 8192 135 #define DFL_LFSBLOCK_SHIFT 13 136 #define DFL_LFSBLOCK_MASK 0x1FFF 137 138 #define DFL_LFSFRAG 1024 139 #define DFL_LFS_FFMASK 0x3FF 140 #define DFL_LFS_FFSHIFT 10 141 #define DFL_LFS_FBMASK 0x7 142 #define DFL_LFS_FBSHIFT 3 143