General conditions for hardware generation

Mnemonic names (mnemonics, MNs)

Mnemonic names must be unique within a given configuration level (controllers, devices).

Two-character alphanumeric or four-character hexadecimal mnemonic names designate devices and controllers. Channels are generated with their channel path identifier.

For each controller, a two-character alphanumeric or four-character hexadecimal mnemonic name can be chosen.

A two-character alphanumeric mnemonic name can always be selected for devices. A four-character hexadecimal device mnemonic (1000 - FFFF) is permitted for all disk and tape devices as well as for network and LOCLAN devices.

Channel or controller without device connection

The channels on boards which were present upon IMPL and are not yet used must also be generated in advance (without connected devices and controllers). It is otherwise not possible to place these channels in service dynamically, see the section "Dynamic modification of the I/O configuration".

Channels can therefore also be generated without the controllers connected to them.

Generation is aborted when a hardware unit is defined for which no device connection has been defined. Exception: the controller for the hardware test, see "Configuration for the hardware test".

Configuration statuses of the hardware units

Neither detached indicators for channel and controller nor removed indicators for controller and device have any effect (they can still be specified for compatibility reasons).

Channels and controllers are generated as “attached”. The Configuration status of a device is specified in the DVC statement.

Paths between channels, controllers and devices are generated as “included”.

The generated Configuration statuses can be modified during system initialization via the startup parameter service (IOCONF parameter record) or while BS2000 is operating using the reconfiguration commands.

The plausibility of the configuration defined and possibly modified using the startup parameter service is checked in the course of system initialization. The rules applied to test this are based in the hardware of the system.

In the course of system initialization, the hardware configuration is checked and made consistent from the channel level to the device level in accordance with the following rules:

• A path is marked as removed (r) if the superordinate hardware unit is detached (d).

• A hardware unit is marked as detached (d) when all paths to superordinate hardware units are removed (r).

Example

A device is attached to only one controller, and this controller is detached. The path from this device to the controller is marked as “removed” (r) and the device itself is marked as “detached” (d).

At generation time, the following rules should be observed during system initialization:

• BS2000 consoles from which the system is to be started must be attached and

• the path to the devices for the home pubset and the paging disks must be included. The device may be detached, it will be attached automatically during system initialization.

Parallel Access Volume (PAV)

Parallel Access Volume (PAV) should be used for ETERNUS disk storage systems, see the “Introduction to System Administration” [4].

IOGEN is used during hardware generation or the /ADD-IO-UNIT command is used during ongoing operation to generate one base device and one or more alias devices for a PAV with the following properties and restrictions:

• The base device and alias device(s) represent the same volume in the disk storage system

• For the alias devices the low-order byte of the LUN must differ from the alias address (see the pav-addr operand of the DVC statement, "DVC - Define device")

• An alias device must have a higher device number than the associated base device

Standard PAV

A standard PAV is characterized by the following properties:

• The base device and alias device(s) are generated on the same controller (see the CTL statement, "CTL - Define controller")

• The base device and alias device(s) have an identical LUN

Extended PAV (XPAV)

For the base controller with the base devices for the real volumes, an alias controller is supported with alias devices and the following properties:

• Only alias devices are connected to the alias controller

• XPAV variant 1

  • The base controller and alias controller are generated on the same controller port

  • The base device and alias device(s) have an identical LUN

• XPAV variant 2

  • The base controller and alias controller are generated on different controller ports

  • The base device and alias device(s) can also have different LUNs, but the low-order bytes of the LUNs must be identical

FastDPAV

The “FastDPAV” function, an optimized DPAV, is offered for Server Units SU /390 that support a modification of the LUN for alias devices when starting an I/O.

With FastDPAV, a pool of FastDPAV aliases is generated for a set of logical volumes with identical channel paths (channel-to-port connection to the disk storage system) without a fixed association with one of these logical volumes. For a FastDPAV alias device, the LUN is only specified or modified when an I/O is started.

FastDPAV aliases are generated as follows:

• Device name: A FastDPAV alias device must have a larger device number than a potentially associated FastDPAV base device.

• Device code: A6

• Configuration state: A or D, not relevant

• LUN: FF00 to FFFF

• Controllers: FastDPAV aliases are generated on their own controllers.

• FastDPAV alias devices must have the same logical control ports as the associated FastDPAV base devices. This means:

  If the base devices have n logical controllers with the lexically ordered mnemonics <b_ctl1> to <b_ctln> and each logical controller <b_ctl_i> has the channel paths <cpidi1,wwpni1> to <cpidik,wwpnik>,
  then the alias devices must also have n logical controllers with the lexically ordered mnemonics <a_ctl1> to <a_ctln> and each logical controller <a_ctli> has the channel connectors <cpidi1,wwpni1> to <cpidik,wwpnik>.

  Lexical ordered means: A-Z before 0-9.