MINIDISK(8R) —

NAME

minidisk − minidisk maintenance utility

DESCRIPTION

Minidisk is a component of the sautil(8R) package of standalone utility programs and is used in maintaining VRM (Virtual Resource Manager) compatible minidisk (partition) tables. Minidisk displays and allows changes to be made to the minidisk directory. It can be used to change the size and location of the IBM 4.3 hard disk partitions. On the IBM 6152 Academic System, minidisk should be used after an IBM/4.3 physical partition has been created with the standalone utility program fdisk(8R).

When AIX (Advanced Interactive Executive) is to be used on the same machine with IBM/4.3, the IBM/4.3 disks must have minidisk tables to ensure on the IBM RT PC VRM and AIX do not overwrite the IBM/4.3 disks.

When first invoked minidisk will prompt for the name of the disk to be examined or changed. See the section below under the disk command for format of the response.

COMMANDS

There are a number of minidisk commands available:

change name field value
changes the value of the field (one of name, iodn, type) specified. The value must be appropriate for the field specified.

create name iodn size type
creates a minidisk with the appropriate name (see NOTE below for the acceptable names). Iodn should be in the range 32736—32751 which is allocated to IBM/4.3. Size is the number of (512-byte) blocks to allocate to the partition. These units can be overridden with the following modifiers behind the size value: "K", for kilobytes; "M", for megabytes; "C", for cylinders; and "T" for tracks. "B" (for blocks) may also be used, although it has no effect since it is the default. For example, specifying a size of "20M" allocates 20 megabytes. Size is always rounded up to the next cylinder boundary on 4.3 partitions; thus a size of one will always cause the remainder of a cylinder to be allocated. Type is the type of the partition; IBM/4.3 partitions have a type of zero, except for the swap/paging area which has type swap. Type can be specified in hexadecimal (see IBM RT PC Virtual Resource Manager Virtual Resource Manager Technical Reference), or as a comma-separated list of types from ipl, vrm, pc, aix, file, swap and nobad.

delete name
deletes minidisk name, after prompting the user for confirmation.

directory
prints the current directory.

disk disk-name
specifies a new disk to be examined. When used in standalone mode, the disk-name should be of the form: hd(unit,2), where unit is one of 0, 1, or 2. When used as a normal utility (this is generally not recommended as the kernel disk driver will not pick up any partition changes until the system is rebooted), disk-name is of the form: /dev/rhdunitc for the hard disk, /dev/rscunitc for the IBM 9331 disk unit (SCSI’s).

help
prints a short description of each command.

initialize
creates an empty minidisk table (for example, makes all the space on the disk available for use). You are prompted for confirmation as this command will make any partitions previously set up unavailable.

list
prints (lists) the current directory. This is a synonym for the directory command.

quit
quits minidisk and returns control to sautil(8R).

standard [cmd]
creates the standard (default) IBM/4.3 partitions (boot, a, b, and g). For this command to be accepted, an initialize command must be given previously. There are several optional arguments to the standard command that cause it to create different variations of partition arrangements:

root
causes standard partitions to be created for normal installation of IBM/4.3. This option should always be used to create the minidisk partitions for the root device on machines with full configurations.

source
causes standard partitions to be created that are suitable for normal intallation of /usr/src.

single
causes a single partition to be created that spans the entire disk.

reduced
causes standard partitions to be created for normal installation of IBM/4.3 on machines with limited disk space. This option should always be used to create the minidisk partitions for the root device on machines with reduced configurations.

minimal
causes standard partitions to be created for normal installation of IBM/4.3 on machines with very limited disk space. This option should always be used to create the minidisk partitions for the root device on machines with minimal configurations.

swap
swaps the primary and secondary copies of the directory. This command is only effective if the copies were initially different (which is usually because either the primary or secondary copy was damaged). By using this command, it is possible to examine both copies to determine which is best used. After selecting the desired copy, the write command can be used to force both copies to be written to the disk. This can also be accomplished by making a change to any minidisk entry.

write
forces the current minidisk record to be written to the disk. As this is done after any change to the directory, this command is useful with the swap command after either the primary or secondary directory copy was damaged.

NOTE

On the IBM RT PC, an IBM/4.3 minidisk must have a name of the form “hdxy” for the hard disk, “scxy” for the SCSI to be taken as a IBM/4.3 disk partition, where x is any character, an y is a letter between “a” and “g”. On the IBM 6152 Academic System, and IBM/4.3 minidisk must have a name of the form “hdxy” to be taken as an IBM/4.3 disk partition, where x is any character (ignored, usually drive number), and y is a letter between “a” and “g”. Note that the drivers ignore a “c” partition. The “c” partition always refers to the whole disk. In addition, any minidisk with the swap type is used as a IBM/4.3 “b” partition (for swapping/paging).

Although minidisks can be created with any size at any location on the disk, the IBM/4.3 disk drivers adjust the start address to be on the next full cylinder boundary and adjust the size accordingly.

When minidisk is used on a disk for the first time, it is likely a “minidisk corrupted” message will be printed; answer “yes” when asked if the minidisk should be initialized, if this is the case.

The defaults used for root and swap are 15884 and 10032 or about 7.5M and 5M. Users are left to decide their disk space requirements and make adjustments if necessary.

IODNs and minidisk types have little meaning in the System/2 environment. An IPL minidisk will (harmlessly) not be created on a drive with less than 68 sectors per cylinder.

EXAMPLE

In this example, minidisk is loaded from the sautil menu. Boldface indicates user input.

4.3 BSD UNIX Standalone Maintenance Program $Revision: 12.0 $
ChoiceDescription
1     boot - boot standalone program or kernel
2     format - format hard disk
3     dump - display disk or diskette (hex)
4     cat - display a file contents (ASCII)
5     ls - print directory of filesystem
6     copy - copy all/part of disk or diskette
7     debugger - display memory, etc.
8     iplsource - set boot order in nvram
9     minidisk - display/change minidisk directory
10    dosboot - boot standalone program or kernel from DOS diskette

Enter the menu choice number desired, then press <Enter>
Choice: 9
disk      hd(0,2)
hd(0,2):
number = 0 level = 0 first = 0 last = 0 bad_block = 0 bad_size = 0
index iodn name           date              start   size type
minidisk directory corrupted
re-initialize minidisk directory [y/n] y
> list
number = 1 level = 0 first = 0 last = 0 bad_block = 138127 bad_size = 1000
index iodn name           date              start   size type
     0     0 FREE                               68 138060 00
> standard
create boot 32736 68 ipl
create hd0a 32737 15912 0
create hd0b 32738 33456 swap
create hd0g 32739 88536 0
> list
number = 5 level = 0 first = 0 last = 4 bad_block = 138127 bad_size = 1000
index iodn name           date              start   size type
     0 32736 boot Thu Jul 31 17:45:09 1986     68     68 01 ipl
    1 32737 hd0a Thu Jul 31 17:45:09 1986    136 15912 00
    2 32738 hd0b Thu Jul 31 17:45:09 1986 16048 33456 20 swap
    3 32739 hd0g Thu Jul 31 17:45:09 1986 49504 88536 00
    4     0 FREE                           138040     88 00
> help
Commands available are:
changechange minidisk parameters
createcreate new minidisk
deletedelete minidisk directory
dirlist minidisk directory
disklook at different disk
helpdisplay short help messages about each command
initializeinitialize (erase) entire minidisk directory
listlist minidisk directory
quitleave minidisk program
standardcreate standard partitions
swapuse secondary minidisk (if primary was bad)
writeforce minidisk directory to disk
> quit

BUGS

Minidisk cannot be used from sautil to change the disk partitions on an scsi.

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