AIX Devices Information

There are 3 types of Devices:

1. Primary Devices
2. Secondary Devices
3. Base Devices

Primary Devices include RAM, Motherboard, CPU.

Secondary Devices include Hard disk, floppy disk, tape drive, printers, drivers, adapters, buses, enclosures, pseudo devices such as error special file, null special files

Secondary devices are of 2 types:

1. Blocking devices which includes cd, floppy, hard disk, tape drives and discs and magnetic tapes.

2. character devices which includes logical devices PV, ttys, modems, routers, terminals, sockets and piping files.

Base Devices include keyboard, mouse etc.

Devices are organized into clusters known as nodes.

All devices have parent child relationship.

Devices connected to the system can have 4 states:

1. Undefined
2. defined
3. Available
4. Stopped

Undefined means devices may be connected to the system but not defined.

Defined means devices connected and defined but still unavailable to the system.

Available means devices are defined and present in the system.

Stopped means devices are unavailable but defined and not known to the system by a device number.

What is Location Code?

It is a path which leads from CPU through the cable to the device. It helps in identifying the physical devices.

It has 4 fields:

1. Drawer
2. Slot
3. Connector
4. Port

Each of the 4 fields has 2 character code assigned.

For eg:

AA – drawer

BB – slot

CC – connector

DD – port

Drawer and slot together makes an Adapter.

Other devices either have AA-BB-CC combination OR AA-BB-CC-DD combination.

This was a general piece of information of Devices.

These thoughts are inspired from various online pdfs and content available.

Take care !