Annotation of wikisrc/guide/misc.mdwn, revision 1.2

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: 
1.2     ! jdf         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
1.1       jdf        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: 
1.2     ! jdf        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,
1.1       jdf        19: at the boot prompt, give the following command:
                     20: 
                     21:     > boot wd0a:netbsd
                     22: 
1.2     ! jdf        23: This boots the kernel on the hard disk (use the correct device, for example sd0a
1.1       jdf        24: for a SCSI disk).
                     25: 
1.2     ! jdf        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
1.1       jdf        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).
1.2     ! jdf        35: Depending on the platform you are using, its usage differs, so you should read
1.1       jdf        36: the manpage and its extensive *EXAMPLES* section.
                     37: 
1.2     ! jdf        38: E.g., if you want to install the bootloader for a ffs filesystem to the
1.1       jdf        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: 
1.2     ! jdf        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
1.1       jdf        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: 
1.2     ! jdf        51: The previous command deletes the disklabel (not the MBR partition table). To
1.1       jdf        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: 
1.2     ! jdf        56: The commands above will only work as expected on the i386 and amd64 ports of
1.1       jdf        57: NetBSD. On other ports, the whole device will end in c, not d (e.g. `rwd0c`).
                     58: 
                     59: ## Speaker
                     60: 
1.2     ! jdf        61: I found this tip on a mailing list (I don't remember the author). To output a
1.1       jdf        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)
1.2     ! jdf        64: driver can be used in the kernel config, which is mapped on `/dev/speaker`. For
1.1       jdf        65: example:
                     66: 
                     67:     echo 'BPBPBPBPBP' > /dev/speaker
                     68: 
1.2     ! jdf        69: *Note*: The `spkr` device is not enabled in the generic kernel; a customized
1.1       jdf        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: 
1.2     ! jdf        78: 1. Boot single user: when the boot prompt appears and the five seconds
1.1       jdf        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)
1.2     ! jdf       102:        #
1.1       jdf       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: 
1.2     ! jdf       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;
1.1       jdf       116: check that you are not losing important information and then delete it:
                    117: 
1.2     ! jdf       118:     # rm /etc/ptmp
1.1       jdf       119: 
1.2     ! jdf       120: *Note*: If the file `/etc/ptmp` exists you can also receive a warning message at
1.1       jdf       121: system startup. For example:
                    122: 
                    123:     root: password file may be incorrect - /etc/ptmp exists
                    124: 
                    125: ## Adding a new hard disk
                    126: 
1.2     ! jdf       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
1.1       jdf       132: different (`wd#` instead of `sd#`).
                    133: 
1.2     ! jdf       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
1.1       jdf       136: NetBSD.
                    137: 
1.2     ! jdf       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
1.1       jdf       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: 
1.2     ! jdf       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
1.1       jdf       155: [[Compiling the kernel|guide/kernel]]).
                    156: 
1.2     ! jdf       157: Now the partitions can be created using the
1.1       jdf       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: 
1.2     ! jdf       177: In this example the hard disk already contains a DOS partition, which will be
1.1       jdf       178: deleted and replaced with a native NetBSD partition. The command
1.2     ! jdf       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
1.1       jdf       181: confirmation before writing, so you can work relaxedly.
                    182: 
                    183: **Disk geometries**
                    184: 
1.2     ! jdf       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
1.1       jdf       191: number of sectors (4226725) divided by 8188 and then by 3.
                    192: 
1.2     ! jdf       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
1.1       jdf       197: we will lose some sectors (4226725 - 4225536 = 1189 sectors = 594 KB).
                    198: 
1.2     ! jdf       199: To create the BIOS partitions the command `fdisk -u` must be used; the result is
1.1       jdf       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: 
1.2     ! jdf       211: Now it's time to create the disklabel for the NetBSD partition. The correct
1.1       jdf       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: 
1.2     ! jdf       229: Now we create some disklabel partitions, editing the `tempfile` as already
1.1       jdf       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: 
1.2     ! jdf       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
1.1       jdf       242: an iterative process.
                    243: 
1.2     ! jdf       244: The final operation is the creation of the file systems for the newly defined
1.1       jdf       245: partitions (`a:` and `e:`).
                    246: 
                    247:     # newfs /dev/rsd0a
                    248:     # newfs /dev/rsd0e
                    249: 
1.2     ! jdf       250: The disk is now ready for usage, and the two partitions can be mounted. For
1.1       jdf       251: example:
                    252: 
                    253:     # mount /dev/sd0a /mnt
                    254: 
1.2     ! jdf       255: If this succeeds, you may want to put an entry for the partition into
1.1       jdf       256: `/etc/fstab`.
                    257: 
                    258: ## How to rebuild the devices in /dev
                    259: 
1.2     ! jdf       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
1.1       jdf       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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