1.\" Copyright (c) 1980, 1988, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)bad144.8 8.1 (Berkeley) 6/6/93 33.\" $NetBSD: bad144.8,v 1.11 2002/06/13 15:25:58 wiz Exp $ 34.\" 35.Dd June 6, 1993 36.Dt BAD144 8 37.Os 38.Sh NAME 39.Nm bad144 40.Nd read/write dec standard 144 bad sector information 41.Sh SYNOPSIS 42.Nm 43.Op Fl c 44.Op Fl f 45.Op Fl v 46.Ar disk 47.Oo 48.Ar sno 49.Op Ar bad ... 50.Oc 51.Nm "" 52.Fl a 53.Op Fl c 54.Op Fl f 55.Op Fl v 56.Ar disk 57.Op Ar bad ... 58.Sh DESCRIPTION 59.Nm 60can be used to inspect the information stored on a disk that is used by 61the disk drivers to implement bad sector forwarding. 62.Pp 63Available options: 64.Pp 65.Bl -tag -width Ds 66.It Fl a 67The argument list consists of new bad sectors to be added to an existing 68list. 69The new sectors are sorted into the list, 70which must have been in order. 71Replacement sectors are moved to accommodate the additions; 72the new replacement sectors are cleared. 73.It Fl c 74Forces an attempt to copy the old sector to the replacement, 75and may be useful when replacing an unreliable sector. 76.It Fl f 77.Pq vax only 78For a RP06, RM03, RM05, Fujitsu Eagle, 79or 80.Tn SMD 81disk on a Massbus, the 82.Fl f 83option may be used to mark the new bad sectors as ``bad'' 84by reformatting them as unusable sectors. 85This option is 86.Em required unless 87the sectors have already been marked bad, 88or the system will not be notified that it should use the replacement sector. 89This option may be used while running multiuser; it is no longer necessary 90to perform format operations while running single-user. 91.It Fl v 92The entire process is described as it happens in gory detail if 93.Fl v 94(verbose) is given. 95.El 96.Pp 97The format of 98the information is specified by 99.Tn DEC 100standard 144, as follows. 101The bad sector information is located in the first 5 even numbered sectors 102of the last track of the disk pack. There are five identical copies of 103the information, described by the 104.Ar dkbad 105structure. 106.Pp 107Replacement sectors are allocated starting with the first sector before 108the bad sector information and working backwards towards the beginning 109of the disk. A maximum of 126 bad sectors are supported. The position 110of the bad sector in the bad sector table determines the replacement 111sector to which it corresponds. 112The bad sectors must be listed in ascending order. 113.Pp 114The bad sector information and replacement sectors are conventionally 115only accessible through the ``c'' file system partition of the disk. If 116that partition is used for a file system, the user is responsible for 117making sure that it does not overlap the bad sector information or any 118replacement sectors. 119Thus, one track plus 126 sectors must be reserved to allow use 120of all of the possible bad sector replacements. 121.Pp 122The bad sector structure is as follows: 123.Bd -literal 124struct dkbad { 125 int32_t bt_csn; /* cartridge serial number */ 126 u_int16_t bt_mbz; /* unused; should be 0 */ 127 u_int16_t bt_flag; /* -1 =\*[Gt] alignment cartridge */ 128 struct bt_bad { 129 u_int16_t bt_cyl; /* cylinder number of bad sector */ 130 u_int16_t bt_trksec; /* track and sector number */ 131 } bt_bad[126]; 132}; 133.Ed 134.Pp 135Unused slots in the 136.Ar bt_bad 137array are filled with all bits set, a putatively 138illegal value. 139.Pp 140.Nm 141is invoked by giving a device name (e.g. wd0, hk0, hp1, etc.). 142With no optional arguments 143it reads the first sector of the last track 144of the corresponding disk and prints out the bad sector information. 145It issues a warning if the bad sectors are out of order. 146.Nm 147may also be invoked with a serial number for the pack and a list 148of bad sectors. 149It will write the supplied information into all copies 150of the bad-sector file, replacing any previous information. 151Note, however, that 152.Nm 153does not arrange for the specified sectors to be marked bad in this case. 154This procedure should only be used to restore known bad sector 155information which was destroyed. 156.Pp 157It is no longer necessary to reboot to allow the kernel 158to reread the bad-sector table from the drive. 159.Sh SEE ALSO 160.Xr badsect 8 161.Sh HISTORY 162The 163.Nm 164command appeared in 165.Bx 4.1 . 166.Sh BUGS 167It should be possible to format disks on-line under 168.Bx 4 . 169.Pp 170It should be possible to mark bad sectors on drives of all type. 171.Pp 172On an 11/750, 173the standard bootstrap drivers used to boot the system do 174not understand bad sectors, 175handle 176.Tn ECC 177errors, or the special 178.Tn SSE 179(skip sector) errors of RM80-type disks. 180This means that none of these errors can occur when reading the file 181.Pa /netbsd 182to boot. Sectors 0-15 of the disk drive 183must also not have any of these errors. 184.Pp 185The drivers which write a system core image on disk after a crash do not 186handle errors; thus the crash dump area must be free of errors and bad 187sectors. 188