HP 3000 Manuals

System Startup, Configuration, and Shutdown Reference Manual

Determining and Selecting Input and Output (I/O) Paths 

The system identifies adapter interfaces to a system bus and the
associated devices by an I/O path.  The I/O path is the address of the
interface hardware and the physical path to reach a device.

When the system is reset or the power is turned on, hardware routines
read and initialize the I/O paths needed to boot the system.  These boot
paths consist of the primary boot path, for booting from disk-resident
software; the alternate boot path, for booting from a system load tape;
and the console boot path, for locating console operator intervention.

Boot paths for the primary boot device, the alternate boot device, and
the console are shown as numbers separated by periods.

Series 922 through Series 949 boot paths 

Each I/O path is constructed "top down" from where the device is
physically attached to the system.  The Series 922 through Series 949 I/O
path is determined by the channel adapter (CA) module number, the device
adapter (DA) slot number, and the device address:

     CA Module Number.DA Slot Number.Device Address

The CA module number specifies the number of card slots in the central
bus (CTB) that the channel adapter is attached to, multiplied by four.
The Series 922 through Series 932 CA modules are assigned a numerical
value of 4 or 8.  The Series 935 CA module is assigned a numerical value
of 4 or 36.  The Series 949 CA module is assigned a numerical value of 8
or 40.

DA slot numbers range from 0 to 13.  Slots 0 through 7 are recommended
for use.

The address of the device itself depends on the adapter.  In addition,
data communication devices may have an additional logical or virtual
device number in the I/O path specification.

For example, in figure 2-3 the CA module number is 4, the HP-IB channel
CIB interface slot is 5, and the magnetic tape device address is 0.  This
establishes an I/O path for the tape drive as 4.5.0.0.0.0.0.0.  Trailing
zeros (those occurring after the third digit) are intended for future
use.


          Figure 2-3.  Series 922 through Series 935 I/O Device Paths 

Series 950 through Series 980 boot paths 

On Series 950 through Series 980 systems, I/O path construction begins
with the bus converter (BUS CONV), which connects the system's main bus
(SMB) and central bus (CTB). The channel adapter connects the central bus
and the channel I/O bus (CIB). The logical construction concludes with
the device adapter, which connects the I/O device to the CIB. An I/O
device connects to a device adapter card through an interface cable.

A Series 950 through Series 980 I/O path is specified as follows:

     BUS CONV/CA Module Number.DA Slot Number.Device Address

The bus converter specifies the number, either 2 or 6, of the interface
slot that contains the adapter boards for the SMB and the central bus.

The CA module number specifies the number of the interface slot that
contains the adapter boards for the central bus and the CIB. The CA
module number is assigned a numerical value of 4, 8, 16, 20, or 24.

DA CIO section slot numbers range from 0 to 4.

The address of the device itself depends on the adapter.  In addition,
data communication devices may have an additional logical or virtual
device number in the I/O path specification.

In figure 2-4, for example, the bus converter is 6, the CA module number
is 4, the HP-IB channel CIB interface slot is 3, and the magnetic tape
device address is 3.  This establishes an I/O path for the tape drive as
6/4.3.3.0.0.0.


          Figure 2-4.  Series 950 through Series 980 I/O Device Paths 

There are several ways to determine the I/O path for devices that are
attached to the system:

   *   Refer to figures 2-3 and 2-4 for address and physical connection
       information.

   *   Generate a list of paths for devices that have already been
       configured by using the LPATH command of the SYSGEN utility IO
       Configurator.  SYSGEN does not tell you if the configured device
       is active or available.  During the system boot (using the ISL
       START command), information on which paths have been configured
       and which devices are available or not available is listed as the
       "System State at Boot Time." (For more information on the system
       state, refer to Chapter 3  and Appendix B .  For more
       information on SYSGEN, refer to Chapter 4 .)

   *   Use the ISL utility, IOMAP, to list the devices on the system.
       (For more information on IOMAP, refer to Appendix E .)  For
       9X8LX and 9X8RX systems, use the ODE utility to list devices on
       the system.

MPE/iX 5.0 Documentation