Annotation of wikisrc/guide/misc.mdwn, revision 1.1
1.1 ! jdf 1: # Miscellaneous operations
! 2:
! 3: This chapter collects various topics, in sparse order
! 4:
! 5: ## Installing the boot manager
! 6:
! 7: ### fdisk
! 8:
! 9: Sysinst, the NetBSD installation program, usually installs the NetBSD boot
! 10: manager on the hard disk. The boot manager can also be installed or reconfigured
! 11: at a later time, if needed, with the
! 12: [fdisk(8)](http://netbsd.gw.com/cgi-bin/man-cgi?fdisk+8+NetBSD-current)
! 13: command. For example:
! 14:
! 15: # fdisk -B wd0
! 16:
! 17: If NetBSD doesn't boot from the hard disk, you can boot it from the installation
! 18: floppy and start the kernel on the hard disk. Insert the installation disk and,
! 19: at the boot prompt, give the following command:
! 20:
! 21: > boot wd0a:netbsd
! 22:
! 23: This boots the kernel on the hard disk (use the correct device, for example sd0a
! 24: for a SCSI disk).
! 25:
! 26: *Note*: Sometimes `fdisk -B` doesn't give the expected result (at least it
! 27: happened to me), probably if you install/remove other operating systems like
! 28: Windows 95 or Linux with LILO. In this case, try running `fdisk -i` (which is
! 29: known as `fdisk /mbr` from DOS) and then run again `fdisk` from NetBSD.
! 30:
! 31: ### installboot
! 32:
! 33: There is another tool for installing a bootloader, named
! 34: [installboot(8)](http://netbsd.gw.com/cgi-bin/man-cgi?installboot+8+NetBSD-current).
! 35: Depending on the platform you are using, its usage differs, so you should read
! 36: the manpage and its extensive *EXAMPLES* section.
! 37:
! 38: E.g., if you want to install the bootloader for a ffs filesystem to the
! 39: partition you have your NetBSD in (in this case, `sd0c`), you would use:
! 40:
! 41: installboot -v /dev/rsd0c /usr/mdec/bootxx_ffs
! 42:
! 43: ## Deleting the disklabel
! 44:
! 45: Though this is not an operation that you need to perform frequently, it can be
! 46: useful to know how to do it in case of need. Please be sure to know exactly what
! 47: you are doing before performing this kind of operation. For example:
! 48:
! 49: # dd if=/dev/zero of=/dev/rwd0c bs=8k count=1
! 50:
! 51: The previous command deletes the disklabel (not the MBR partition table). To
! 52: completely delete the disk, the whole device `rwd0d` must be used. For example:
! 53:
! 54: # dd if=/dev/zero of=/dev/rwd0d bs=8k
! 55:
! 56: The commands above will only work as expected on the i386 and amd64 ports of
! 57: NetBSD. On other ports, the whole device will end in c, not d (e.g. `rwd0c`).
! 58:
! 59: ## Speaker
! 60:
! 61: I found this tip on a mailing list (I don't remember the author). To output a
! 62: sound from the speaker (for example at the end of a long script) the
! 63: [spkr(4)](http://netbsd.gw.com/cgi-bin/man-cgi?spkr+4+NetBSD-current)
! 64: driver can be used in the kernel config, which is mapped on `/dev/speaker`. For
! 65: example:
! 66:
! 67: echo 'BPBPBPBPBP' > /dev/speaker
! 68:
! 69: *Note*: The `spkr` device is not enabled in the generic kernel; a customized
! 70: kernel is needed.
! 71:
! 72: ## Forgot root password?
! 73:
! 74: If you forget root's password, not all is lost and you can still recover the
! 75: system with the following steps: boot single user, mount `/` and change root's
! 76: password. In detail:
! 77:
! 78: 1. Boot single user: when the boot prompt appears and the five seconds
! 79: countdown starts, give the following command:
! 80:
! 81: > boot -s
! 82:
! 83: 2. At the following prompt
! 84:
! 85: Enter pathname of shell or RETURN for sh:
! 86:
! 87: press Enter.
! 88:
! 89: 3. Write the following commands:
! 90:
! 91: # fsck -y /
! 92: # mount -u /
! 93: # fsck -y /usr
! 94: # mount /usr
! 95:
! 96: 4. Change root's password:
! 97:
! 98: # passwd root
! 99: Changing local password for root.
! 100: New password: (not echoed)
! 101: Retype new password: (not echoed)
! 102: #
! 103:
! 104: 5. Exit the shell to go to multiuser mode.
! 105:
! 106: # exit
! 107:
! 108:
! 109: If you get the error `Password file is busy`, please see the section below.
! 110:
! 111: ## Password file is busy?
! 112:
! 113: If you try to modify a password and you get the mysterious message `Password
! 114: file is busy, it probably means that the file `/etc/ptmp` has not been deleted
! 115: from the system. This file is a temporary copy of the `/etc/master.passwd` file;
! 116: check that you are not losing important information and then delete it:
! 117:
! 118: # rm /etc/ptmp
! 119:
! 120: *Note*: If the file `/etc/ptmp` exists you can also receive a warning message at
! 121: system startup. For example:
! 122:
! 123: root: password file may be incorrect - /etc/ptmp exists
! 124:
! 125: ## Adding a new hard disk
! 126:
! 127: This section describes how to add a new hard disk to an already working NetBSD
! 128: system. In the following example a new SCSI controller and a new hard disk,
! 129: connected to the controller, will be added. If you don't need to add a new
! 130: controller, skip the relevant part and go to the hard disk configuration. The
! 131: installation of an IDE hard disk is identical; only the device name will be
! 132: different (`wd#` instead of `sd#`).
! 133:
! 134: As always, before buying new hardware, consult the hardware compatibility list
! 135: of NetBSD or ask on a mailing list to make sure the new device is supported by
! 136: NetBSD.
! 137:
! 138: When the SCSI controller has been physically installed in the system and the new
! 139: hard disk has been connected, it's time to restart the computer and check that
! 140: the device is correctly detected, using the
! 141: [dmesg(8)](http://netbsd.gw.com/cgi-bin/man-cgi?dmesg+8+NetBSD-current)
! 142: command. This is the sample output for an NCR-875 controller:
! 143:
! 144: ncr0 at pci0 dev 15 function 0: ncr 53c875 fast20 wide scsi
! 145: ncr0: interrupting at irq 10
! 146: ncr0: minsync=12, maxsync=137, maxoffs=16, 128 dwords burst, large dma fifo
! 147: ncr0: single-ended, open drain IRQ driver, using on-chip SRAM
! 148: ncr0: restart (scsi reset).
! 149: scsibus0 at ncr0: 16 targets, 8 luns per target
! 150: sd0(ncr0:2:0): 20.0 MB/s (50 ns, offset 15)
! 151: sd0: 2063MB, 8188 cyl, 3 head, 172 sec, 512 bytes/sect x 4226725 sectors
! 152:
! 153: If the device doesn't appear in the output, check that it is supported by the
! 154: kernel that you are using; if necessary, compile a customized kernel (see
! 155: [[Compiling the kernel|guide/kernel]]).
! 156:
! 157: Now the partitions can be created using the
! 158: [fdisk(8)](http://netbsd.gw.com/cgi-bin/man-cgi?fdisk+8+NetBSD-current)
! 159: command. First, check the current status of the disk:
! 160:
! 161: # fdisk sd0
! 162: NetBSD disklabel disk geometry:
! 163: cylinders: 8188 heads: 3 sectors/track: 172 (516 sectors/cylinder)
! 164:
! 165: BIOS disk geometry:
! 166: cylinders: 524 heads: 128 sectors/track: 63 (8064 sectors/cylinder)
! 167:
! 168: Partition table:
! 169: 0: sysid 6 (Primary 'big' DOS, 16-bit FAT (> 32MB))
! 170: start 63, size 4225473 (2063 MB), flag 0x0
! 171: beg: cylinder 0, head 1, sector 1
! 172: end: cylinder 523, head 127, sector 63
! 173: 1: <UNUSED>
! 174: 2: <UNUSED>
! 175: 3: <UNUSED>
! 176:
! 177: In this example the hard disk already contains a DOS partition, which will be
! 178: deleted and replaced with a native NetBSD partition. The command
! 179: `fdisk -u sd0` allows to modify interactively the partitions. The modified data
! 180: will be written on the disk only before exiting and fdisk will request a
! 181: confirmation before writing, so you can work relaxedly.
! 182:
! 183: **Disk geometries**
! 184:
! 185: The geometry of the disk reported by fdisk can appear confusing. Dmesg reports
! 186: 4226725 sectors with 8188/3/172 for C/H/S, but 8188\*3\*172 gives 4225008 and
! 187: not 4226725. What happens is that most modern disks don't have a fixed geometry
! 188: and the number of sectors per track changes depending on the cylinder: the only
! 189: interesting parameter is the number of sectors. The disk reports the C/H/S
! 190: values but it's a fictitious geometry: the value 172 is the result of the total
! 191: number of sectors (4226725) divided by 8188 and then by 3.
! 192:
! 193: To make things more confusing, the BIOS uses yet another *fake* geometry (C/H/S
! 194: 524/128/63) which gives a total of 4225536, a value which is a better
! 195: approximation to the real one than 425008. To partition the disk we will use the
! 196: BIOS geometry, to maintain compatibility with other operating systems, although
! 197: we will lose some sectors (4226725 - 4225536 = 1189 sectors = 594 KB).
! 198:
! 199: To create the BIOS partitions the command `fdisk -u` must be used; the result is
! 200: the following:
! 201:
! 202: Partition table:
! 203: 0: sysid 169 (NetBSD)
! 204: start 63, size 4225473 (2063 MB), flag 0x0
! 205: beg: cylinder 0, head 1, sector 1
! 206: end: cylinder 523, head 127, sector 63
! 207: 1: <UNUSED>
! 208: 2: <UNUSED>
! 209: 3: <UNUSED>
! 210:
! 211: Now it's time to create the disklabel for the NetBSD partition. The correct
! 212: steps to do this are:
! 213:
! 214: # disklabel sd0 > tempfile
! 215: # vi tempfile
! 216: # disklabel -R -r sd0 tempfile
! 217:
! 218: If you try to create the disklabel directly with
! 219:
! 220: # disklabel -e sd0
! 221:
! 222: you get the following message
! 223:
! 224: disklabel: ioctl DIOCWDINFO: No disk label on disk;
! 225: use "disklabel -I" to install initial label
! 226:
! 227: because the disklabel does not yet exist on the disk.
! 228:
! 229: Now we create some disklabel partitions, editing the `tempfile` as already
! 230: explained. The result is:
! 231:
! 232: # size offset fstype [fsize bsize cpg]
! 233: a: 2048004 63 4.2BSD 1024 8192 16 # (Cyl. 0*- 3969*)
! 234: c: 4226662 63 unused 0 0 # (Cyl. 0*- 8191*)
! 235: d: 4226725 0 unused 0 0 # (Cyl. 0 - 8191*)
! 236: e: 2178658 2048067 4.2BSD 1024 8192 16 # (Cyl. 3969*- 8191*)
! 237:
! 238: *Note*: When the disklabel has been created it is possible to optimize it
! 239: studying the output of the command `newfs -N /dev/rsd0a`, which warns about
! 240: the existence of unallocated sectors at the end of a disklabel partition. The
! 241: values reported by newfs can be used to adjust the sizes of the partitions with
! 242: an iterative process.
! 243:
! 244: The final operation is the creation of the file systems for the newly defined
! 245: partitions (`a:` and `e:`).
! 246:
! 247: # newfs /dev/rsd0a
! 248: # newfs /dev/rsd0e
! 249:
! 250: The disk is now ready for usage, and the two partitions can be mounted. For
! 251: example:
! 252:
! 253: # mount /dev/sd0a /mnt
! 254:
! 255: If this succeeds, you may want to put an entry for the partition into
! 256: `/etc/fstab`.
! 257:
! 258: ## How to rebuild the devices in /dev
! 259:
! 260: First shutdown to single user, partitions still mounted `rw` (read-write); You
! 261: can do that by just typing `shutdown now` while you are in multi user mode, or
! 262: reboot with the `-s` option and make `/` and `/dev` read-writable by doing.
! 263:
! 264: # mount -u /
! 265: # mount -u /dev
! 266:
! 267: Then:
! 268:
! 269: # mkdir /newdev
! 270: # cd /newdev
! 271: # cp /dev/MAKEDEV* .
! 272: # sh ./MAKEDEV all
! 273: # cd /
! 274: # mv dev olddev
! 275: # mv newdev dev
! 276: # rm -r olddev
! 277:
! 278: Or if you fetched all the sources in `/usr/src`:
! 279:
! 280: # mkdir /newdev
! 281: # cd /newdev
! 282: # cp /usr/src/etc/MAKEDEV.local .
! 283: # ( cd /usr/src/etc ; make MAKEDEV )
! 284: # cp /usr/src/etc/obj*/MAKEDEV .
! 285: # sh ./MAKEDEV all
! 286: # cd /
! 287: # mv dev olddev; mv newdev dev
! 288: # rm -r olddev
! 289:
! 290: You can determine $arch by
! 291:
! 292: # uname -m
! 293:
! 294: or
! 295:
! 296: # sysctl hw.machine_arch
! 297:
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