The HLUNIT (Specify Halt/Load Unit) command displays or specifies the halt/load unit information. This command can specify or display the following halt/load devices:

This information is maintained by the console. The halt/load pack is the pack containing such information as the operating system and structure tables. The alternate halt/load pack is used if problems occur with the primary halt/load pack. The halt/load ODT is available to primitive software (LOADER and SATAPEDUMP). The alternate halt/load pack specification can be deleted by this command.

When you request halt/load information, the system displays the unit type, unit number, and path information. When you designate a new halt/load ODT, you can specify only the unit type and unit number. The MCP selects the path to the unit. When you specify a new halt/load pack (whether it is the primary halt/load pack or the alternate halt/load pack), you can include the path to the unit. If you do not give a path for the pack unit, the system selects a path.

Syntax

           ┌◄───────────────────────── , ──────────────────────────┐  
── HLUNIT ─┴─┬─────────────────────────────────────────────────┬───┴─────┤
             ├─ /1\ ── PK ── <unit number> ────────────────────┤
             ├─ /1\ ── PK (BACKUP) ── <unit number> ───────────┤
             ├─ /1\ ── - ── PK (BACKUP) ───────────────────────┤
             ├─ /1\ ── SC ── <unit number> ────────────────────┤
             ├─ /1\ ── CD ── <unit number> ────────────────────┤
             └─ /1\ ── TAPE ── <unit number> ──────────────────┘

Explanation

HLUNIT

Displays all the halt/load unit information, including the packs and the ODT that are specified as halt/load units.

HLUNIT CD <unit number>

When this command is specified, a Force Dump is able to automatically initiate when a CD-R is mounted on the CD-ROM or CD-RW drive. This allows automatic force dumps to proceed when requested from the MCP on an unattended system.

HLUNIT PK <unit number>

Designates the pack identified by the unit number as the new halt/load pack.

HLUNIT PK (BACKUP) <unit number>

Designates the pack identified by the unit number as the new alternate halt/load unit.

HLUNIT − PK (BACKUP)

Designates the alternate halt/load unit parameter to be cleared.

HLUNIT SC <unit number>

Designates the ODT (also known as the system console) identified by the unit number as the new halt/load ODT.

HLUNIT TAPE <unit number>

When this command is specified, a Force Dump is able to automatically initiate when a "DUMMMP" scratch tape is mounted on the tape unit. This allows automatic force dumps to proceed when requested from the MCP on an unattended system. The syntax for the command allows either TAPE or MT to be specified as the device (that is, HLUNIT  MT <unit number> or HLUNIT TAPE <unit number>).

Examples

Example 1

This example shows the display generated by an HLUNIT command:

HLUNIT

     HALT/LOAD DISK                   =       13
     HALT/LOAD DISK (BACKUP)           NOT SPECIFIED
     HALT/LOAD ODT                     =       58

Example 2

The following input changes the halt/load disk information to the unit number and path for PK 48. The I/O processor selects the path. The new halt/load information is then displayed.

HLUNIT PK 48

Example 3

Like the previous example, the following input changes the halt/load ODT information to the unit number and path for ODT 3:

HLUNIT SC 3

Considerations for Use

When you halt/load the system, the MCP automatically places mirrors of critical disks—such as the halt/load family, the log family, and the catalog family—into the auditing state so that write operations can complete before the mirrored copies come online. If the OP 24 (OKTIMEANDDATE) is set, the MCP waits for you to answer the message “PLEASE VERIFY TIME AND DATE.” You must enter either TIMEOK or <mix number> OK. During this delay, if the audit trail, which is maintained in memory, is lost, the mirrored copies of the critical disks are also lost.