Logical partition concept: IOP
The IOP attaches to the system I/O bus and one or more input/output adapters (IOAs). The IOP processes instructions from the server and works with the IOAs to control the I/O devices.
There are many different kinds of IOPs.
- Some IOPs can only support one type of I/O device. In this case the IOA is embedded in the IOP so you can not remove the IOA or change it.
- Some IOPs can support multiple device types, but only one at a time. The type of IOA that is attached determines what device you can use. IOAs on these IOPs can be changed with another IOA to support a different I/O device. The IOA and the IOP work together to control the device.
- Some IOPs can support multiple types of I/O devices at the same time. These are known as Multifunction IOPs (MFIOP) or Combined function IOPs (CFIOP). Multifunction IOPs connect to a variety of different IOAs. For instance, an MFIOP could support disk units, workstations, a communications line, and removable media devices.
- A Combined function IOP can connect to a variety of different IOAs. For instance, a CFIOP could support disk units, a console, and communications hardware. The CFIOP contains some of the same capabilities as an MFIOP, as well as Ethernet and token-ring controllers. IOAs for the supported types of I/O devices attach to the IOP.
There are several important I/O devices in the server. These include the load source disk unit, the alternate IPL device, the system console, and the electronic customer support hardware. The server needs to know where to locate these special devices on secondary partitions. When you create a logical partition, you need to identify the IOPs that control these important devices:
- The IOP that controls the disk unit that will be the load source.
- The IOP that controls the console.
- The IOP that controls the alternate IPL device.
- The IOP that controls the electronic customer support line.
A system with logical partitions needs to have the correct IOP feature codes for the load source disk unit and alternate IPL devices. Without the correct hardware, the secondary partitions will not function correctly.
The system reports all errors that involve IOPs to the product activity log (PAL) in the logical partition that owns the IOP. However, the system may report errors in the PAL of the primary partition against load source IOPs. This may occur when a secondary partition restarts.
- Logical partition concept: IOP and device switching
If you select to partition at the IOP-level, you can switch certain IOPs and all its attached devices between partitions that share the same bus dynamically.- Logical partition concept: tagged resource
A tagged resource is an IOP that you select because it controls a device that performs a specific function for a logical partition.
Parent topic:
Hardware for logical partitionsRelated concepts
Logical partition concept: Bus Logical partition concept: Bus-level and IOP-level I/O partitions Dynamically switching IOPs between partitions Logical partition concept: Expansion unit Logical partition concept: Disk units Logical partition concept: Removable media device and alternate restart (IPL) devices Logical partition concept: Console Logical partition concept: Load source