DISKLABEL(8) BSD System Manager's Manual DISKLABEL(8) NNAAMMEE ddiisskkllaabbeell - read and write disk pack label SSYYNNOOPPSSIISS ddiisskkllaabbeell [--rr] _d_i_s_k ddiisskkllaabbeell --ww [--rr] _d_i_s_k _d_i_s_k_t_y_p_e [_p_a_c_k_i_d] ddiisskkllaabbeell --ee [--rr] _d_i_s_k ddiisskkllaabbeell --RR [--rr] _d_i_s_k _p_r_o_t_o_f_i_l_e ddiisskkllaabbeell [--NNWW] _d_i_s_k ddiisskkllaabbeell --BB [--bb _b_o_o_t_1 [--ss _b_o_o_t_2]] _d_i_s_k [_d_i_s_k_t_y_p_e] ddiisskkllaabbeell --ww --BB [--bb _b_o_o_t_1 [--ss _b_o_o_t_2]] _d_i_s_k _d_i_s_k_t_y_p_e [_p_a_c_k_i_d] ddiisskkllaabbeell --RR --BB [--bb _b_o_o_t_1 [--ss _b_o_o_t_2]] _d_i_s_k _p_r_o_t_o_f_i_l_e [_d_i_s_k_t_y_p_e] DDEESSCCRRIIPPTTIIOONN DDiisskkllaabbeell can be used to install, examine or modify the label on a disk drive or pack. When writing the label, it can be used to change the drive identification, the disk partitions on the drive, or to replace a damaged label. On some systems, ddiisskkllaabbeell can be used to install boot- strap code as well. There are several forms of the command that read (display), install or edit the label on a disk. Each form has an addi- tional option, --rr, which causes the label to be read from or written to the disk directly, rather than going through the system's in-core copy of the label. This option may allow a label to be installed on a disk with- out kernel support for a label, such as when labels are first installed on a system; it must be used when first installing a label on a disk. The specific effect of --rr is described under each command. The read and install forms also support the --BB option to install bootstrap code. These varients are described later. The first form of the command (read) is used to examine the label on the named disk drive (e.g. sd0 or /dev/rsd0c). It will display all of the parameters associated with the drive and its partition layout. Unless the --rr flag is given, the kernel's in-core copy of the label is dis- played; if the disk has no label, or the partition types on the disk are incorrect, the kernel may have constructed or modified the label. If the --rr flag is given, the label from the raw disk will be displayed rather than the in-core label. The second form of the command, with the --ww flag, is used to write a standard label on the designated drive. The required arguments to ddiisskkllaabbeell are the drive to be labelled (e.g. sd0), and the drive type as described in the disktab(5) file. The drive parameters and partitions are taken from that file. If different disks of the same physical type are to have different partitions, it will be necessary to have separate disktab entries describing each, or to edit the label after installation as described below. The optional argument is a pack identification string, up to 16 characters long. The pack id must be quoted if it con- tains blanks. If the --rr flag is given, the disk sectors containing the label and bootstrap will be written directly. A side-effect of this is that any existing bootstrap code will be overwritten and the disk ren- dered unbootable. If --rr is not specified, the existing label will be up- dated via the in-core copy and any bootstrap code will be unaffected. If the disk does not already have a label, the --rr flag must be used. In ei- ther case, the kernel's in-core label is replaced. An existing disk label may be edited by using the --ee flag. The label is read from the in-core kernel copy, or directly from the disk if the --rr flag is also given. The label is formatted and then supplied to an edi- tor for changes. If no editor is specified in an EDITOR environment variable, vi(1) is used. When the editor terminates, the formatted label is reread and used to rewrite the disk label. Existing bootstrap code is unchanged regardless of whether --rr was specified. With the --RR flag, ddiisskkllaabbeell is capable of restoring a disk label that was formatted in a prior operation and saved in an ascii file. The prototype file used to create the label should be in the same format as that pro- duced when reading or editing a label. Comments are delimited by _# and newline. As with --ww, any existing bootstrap code will be clobbered if --rr is specified and will be unaffected otherwise. The --NNWW flags for ddiisskkllaabbeell explicitly disallow and allow, respectively, writing of the pack label area on the selected disk. The final three forms of ddiisskkllaabbeell are used to install boostrap code on machines where the bootstrap is part of the label. The bootstrap code is comprised of one or two boot programs depending on the machine. The --BB option is used to denote that bootstrap code is to be installed. The --rr flag is implied by --BB and never needs to be specified. The name of the boot program(s) to be installed can be selected in a variety of ways. First, the names can be specified explicitly via the --bb and --ss flags. On machines with only a single level of boot program, --bb is the name of that program. For machines with a two-level bootstrap, --bb indicates the pri- mary boot program and --ss the secondary boot program. If the names are not explicitly given, standard boot programs will be used. The boot pro- grams are located in _/_u_s_r_/_m_d_e_c. The names of the programs are taken from the ``b0'' and ``b1'' parameters of the disktab(5) entry for the disk if _d_i_s_k_t_y_p_e was given and its disktab entry exists and includes those param- eters. Otherwise, boot program names are derived from the name of the disk. These names are of the form _b_a_s_e_n_a_m_eboot for the primary (or only) bootstrap, and boot_b_a_s_e_n_a_m_e for the secondary bootstrap; for example, _/_u_s_r_/_m_d_e_c_/_s_d_b_o_o_t and _/_u_s_r_/_m_d_e_c_/_b_o_o_t_s_d if the disk device is _s_d_0. The first of the three boot-installation forms is used to install boot- strap code without changing the existing label. It is essentially a read command with respect to the disk label itself and all options are related to the specification of the boot program as described previously. The final two forms are analogous to the basic write and restore versions ex- cept that they will install bootstrap code in addition to a new label. FFIILLEESS /etc/disktab /usr/mdec/_x_xboot /usr/mdec/boot_x_x EEXXAAMMPPLLEESS disklabel sd0 Display the in-core label for sd0 as obtained via _/_d_e_v_/_r_s_d_0_c. disklabel -w -r /dev/rsd0c sd2212 foo Create a label for sd0 based on information for ``sd2212'' found in _/_e_t_c_/_d_i_s_k_t_a_b. Any existing bootstrap code will be clobbered. disklabel -e -r sd0 Read the on-disk label for sd0, edit it and reinstall in-core as well as on-disk. Existing bootstrap code is unaffected. disklabel -R sd0 mylabel Restore the on-disk and in-core label for sd0 from information in _m_y_l_a_b_e_l. Existing bootstrap code is unaffected. disklabel -B sd0 Install a new bootstrap on sd0. The boot code comes from _/_u_s_r_/_m_d_e_c_/_s_d_b_o_o_t and possibly _/_u_s_r_/_m_d_e_c_/_b_o_o_t_s_d. On-disk and in-core la- bels are unchanged. disklabel -w -B /dev/rsd0c -b newboot sd2212 Install a new label and bootstrap. The label is derived from disktab in- formation for ``sd2212'' and installed both in-core and on-disk. The bootstrap code comes from the file _/_u_s_r_/_m_d_e_c_/_n_e_w_b_o_o_t. SSEEEE AALLSSOO disktab(5), disklabel(5) DDIIAAGGNNOOSSTTIICCSS The kernel device drivers will not allow the size of a disk partition to be decreased or the offset of a partition to be changed while it is open. Some device drivers create a label containing only a single large parti- tion if a disk is unlabeled; thus, the label must be written to the ``a'' partition of the disk while it is open. This sometimes requires the de- sired label to be set in two steps, the first one creating at least one other partition, and the second setting the label on the new partition while shrinking the ``a'' partition. On some machines the bootstrap code may not fit entirely in the area al- located for it by some filesystems. As a result, it may not be possible to have filesystems on some partitions of a ``bootable'' disk. When in- stalling bootstrap code, ddiisskkllaabbeell checks for these cases. If the in- stalled boot code would overlap a partition of type FS_UNUSED it is marked as type FS_BOOT. The newfs(8) utility will disallow creation of filesystems on FS_BOOT partitions. Conversely, if a partition has a type other than FS_UNUSED or FS_BOOT, ddiisskkllaabbeell will not install bootstrap code that overlaps it. BBUUGGSS When a disk name is given without a full pathname, the constructed device name uses the ``a'' partition on the tahoe, the ``c'' partition on all others. 4.2 Berkeley Distribution June 5, 1993 3