17.1 Devices and Physical Paths

   

All HP-9000 series servers and workstations use PA-RISC processors that are connected to several types of device adapters by using buses. All devices are connected to these device adapters. HP systems use many different types of buses, so you need to specify what type of expansion card you need. The buses that are used in HP systems are:

  • Extended Industry Standard Architecture (EISA)

  • General System Connect (GSC)

  • Hewlett-Packard Precision Bus (HP-PB)

  • High Speed System Connect (HSC)

  • PCI

Each bus has its own characteristics, such as clock speed, data throughput, and signaling. The type of adapter is also different for each bus. For example, you will find different Ethernet adapters for PCI and GSC buses.

Common Types of Device Adapters

Some of the device adapters commonly used in HP-9000 systems are listed here. This list does not include all types of adapters; there are many others.

SCSI adapters Small Computer System Interface (SCSI) adapters are used to connect disk drives, tape drives, and CD-ROM drives to the system. Many devices can be connected to one adapter. There are different standards for SCSI adapters used today. The Fast/Wide SCSI adapter is the fastest of all types and has the capability of transferring data at the speed of 20 Mbytes per second. It can support up to 15 devices on a single adapter. Standard SCSI adapters support seven devices and can have a throughput of 5 Mbytes per second. Fast/Narrow or differential SCSI can support up to seven devices and have a throughput of 10 Mbytes per second. You need to purchase a particular type of adapter after verifying the type of bus present in your system.
  All devices attached to SCSI adapters have a number that determines the priority of the device. The SCSI controller itself uses address 7. On SCSI adapters to which you can attach seven devices, device number 6 has the highest priority and device number 0 has the lowest priority. If you are using a Fast/Wide SCSI adapters the additional addresses have lower priorities than 0. Number 15 has a lower priority than number 0 and number 8 has the least priority level. The priority ordering for a Fast/Wide SCSI is: 7,6,5,4,3,2,1,0,15,14,13,12,11,10,9,8.
  Care must be taken while powering up and down the SCSI devices. All SCSI devices must be powered up before starting the system and powered off after the system is shut down. No device should be attached or detached to a running system.
Multiplexer A multiplexer or MUX is used to connect serial devices to the system. Typically, this is used for connecting modems, terminals, and any serial plotter or printer. A variety of MUXs is available from Hewlett-Packard.
LAN card LAN/9000 supports Ethernet and IEEE 802.3 networks and is used to connect your machine to a local area network. Hewlett-Packard manufactures LAN cards for different buses, topologies, and speeds.

You can add a new device adapter any time you want. For example, to have a network-efficient server, you may add Gigabit Ethernet to your system. Similarly, you can add SCSI adapters to increase the number of disk drives in the system.

Hardware Paths

A hardware path indicates the location of a device in your system. Typically, a hardware path is a string of numbers separated by the slash ( / ) and dot ( . ) symbols. Starting from the left, the first part of the device path is usually a bus number. This is followed by a slash ( / ) and then a bus converter number (if any). Then there are some other numbers separated by dots. These numbers show the path to the device in a systematic way.

Let us analyze a device path name . A hardware path of 8/12.5.0 represents a SCSI disk connected to the system. The number 8 represents a bus in the system. The number 12 is the address of the SCSI adapter on the bus. The disk is connected to that SCSI adapter at address 5, having a logical unit number 0. Similarly, hardware address 8/5/0 represents a fiber channel adapter connected to bus 8, bus converter number 5, and adapter number 0. On the backside of an HP-9000 server, you can see expansion slots, and some of these numbers may be present there. To list the devices in your system, you can use the ioscan command, which shows the hardware paths of all devices connected to your system. A typical output of this command is as follows .

 #  ioscan -f  Class       I  H/W Path     Driver      S/W State H/W Type  Description ======================================================================== bc          0               root        CLAIMED   BUS_NEXUS bc          1  8            ccio        CLAIMED   BUS_NEXUS I/O Adapter ext_bus     0  8/0          c720        CLAIMED   INTERFACE GSC add-on                                                   Fast/Wide SCSI Interface target      0  8/0.7        tgt         CLAIMED   DEVICE ctl         0  8/0.7.0      sctl        CLAIMED   DEVICE    Initiator ext_bus     1  8/4          c720        CLAIMED   INTERFACE GSC add-on                                                   Fast/Wide SCSI Interface bc          2  10           ccio        CLAIMED   BUS_NEXUS I/O Adapter ext_bus     2  10/0         c720        CLAIMED   INTERFACE GSC built-in                                                   Fast/Wide SCSI Interface target     13  10/0.1       tgt         CLAIMED   DEVICE disk       16  10/0.1.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34371W target     14  10/0.2       tgt         CLAIMED   DEVICE disk       17  10/0.2.0     sdisk       CLAIMED   DEVICE    SEAGATEST34572WC target     15  10/0.3       tgt         CLAIMED   DEVICE disk       18  10/0.3.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34371W target     16  10/0.4       tgt         CLAIMED   DEVICE disk       19  10/0.4.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34371W target     17  10/0.5       tgt         CLAIMED   DEVICE disk       20  10/0.5.0     sdisk       CLAIMED   DEVICE    SEAGATE ST15150W target     18  10/0.6       tgt         CLAIMED   DEVICE disk       21  10/0.6.0     sdisk       CLAIMED   DEVICE    SEAGATE ST15150W target     19  10/0.7       tgt         CLAIMED   DEVICE ctl         2  10/0.7.0     sctl        CLAIMED   DEVICE    Initiator bc          3  10/4         bc          CLAIMED   BUS_NEXUS Bus Converter tty         0  10/4/0       mux2        CLAIMED   INTERFACE MUX lan         0  10/4/4       btlan1      CLAIMED   INTERFACE HP HP-PB 100 Base TX  card lan         1  10/4/8       btlan1      CLAIMED   INTERFACE HP HP-PB 100 Base TX  card ba          0  10/12        bus_adapter CLAIMED   BUS_NEXUS Core I/O Adapter ext_bus     3  10/12/5      c720        CLAIMED   INTERFACE Built-in SCSI target     20  10/12/5.0    tgt         CLAIMED   DEVICE tape        0  10/12/5.0.0  stape       CLAIMED   DEVICE    HP      C1537A target     21  10/12/5.2    tgt         CLAIMED   DEVICE disk       22  10/12/5.2.0  sdisk       CLAIMED   DEVICE    TOSHIBA CD-ROM target     22  10/12/5.7    tgt         CLAIMED   DEVICE ctl         3  10/12/5.7.0  sctl        CLAIMED   DEVICE    Initiator lan         4  10/12/6      lan2        CLAIMED   INTERFACE Built-in LAN ps2         0  10/12/7      ps2         CLAIMED   INTERFACE Built-in                                                   Keyboard/Mouse processor   0  32           processor   CLAIMED   PROCESSOR Processor processor   1  34           processor   CLAIMED   PROCESSOR Processor memory      0  49           memory      CLAIMED   MEMORY    Memory # 

A short description of the fields in the ioscan command output is presented here.

Class Shows the category of the device.
I Instance: When multiple devices or adapters of the same category are present, they are distinguished from one another by instance numbers. Usually instance numbers are assigned at installation time.
H/W Path This is the hardware path as already discussed in this chapter.
Driver Name of the driver that controls the device. The device drivers are built into the HP-UX kernel. When adding a device that needs a new device driver, the kernel needs to be reconfigured.
S/W State CLAIMED means the device driver is loaded in the kernel and is bound to the device. UNCLAIMED means the device driver is not available in the kernel for that device.
H/W Type Shows what type of device it is.
Description A short description of the device.

The ioscan command can be used, with the help of command line switches, to list devices of a specific type only or devices connected to a particular adapter.


   
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HP Certified
HP Certified: HP-UX System Administration
ISBN: 0130183741
EAN: 2147483647
Year: 2000
Pages: 390
Authors: Rafeeq Rehman

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