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HP-UX 11.3i passthru directory (/dev/pt)

heymanj
Occasional Contributor

HP-UX 11.3i passthru directory (/dev/pt)

I have two HP-UX 11.3i systems that I'm working with.

 

When I attach fc connections to one of the systems (systemA), the target SCSI Processor device is visible in the /dev/pt (passthru) directory with the entries /dev/pt/pt2 and /dev/pt/pt3.

On the second system (systemB), when I make the same connections to the the same target, there is no /dev/pt, and hence no /dev/pt/pt? devices.

 

In comparing the output of swlist on systemA and systemB, there is nothing sticking out that says "Passthru module" (or somesuch) on one system but not on the other. 

 

Is there a particular software package that needs to be installed to have the /dev/pt hierarchy created?

3 REPLIES
Matti_Kurkela
Honored Contributor

Re: HP-UX 11.3i passthru directory (/dev/pt)

The HP-UX kernel module responsible for the passthru device entries is named "esctl".

Although I'm pretty sure that the driver exists on your systemB, you can use "kcmodule | grep esctl" to verify it. The normal response would be:

# kcmodule |grep esctl
esctl               static  best   

 

By default, only if a storage device does not get assigned to a more specific driver, it will get a /dev/pt device node.

You can use "mksf -P" with appropriate options to create pass-thru device entries for other devices.

 

For more information, Google for a HP whitepaper named "HP-UX 11i v3 Mass Storage Device Naming".

MK
heymanj
Occasional Contributor

Re: HP-UX 11.3i passthru directory (/dev/pt)


Matti_Kurkela wrote:

The HP-UX kernel module responsible for the passthru device entries is named "esctl".

Although I'm pretty sure that the driver exists on your systemB, you can use "kcmodule | grep esctl" to verify it. The normal response would be:

# kcmodule |grep esctl
esctl               static  best   

 

By default, only if a storage device does not get assigned to a more specific driver, it will get a /dev/pt device node.

You can use "mksf -P" with appropriate options to create pass-thru device entries for other devices.

 

For more information, Google for a HP whitepaper named "HP-UX 11i v3 Mass Storage Device Naming".


MK,

 

As you suspected, both machines show the existance of the esctl kernel module with the  "static best" attributes.

 

It makes sense that the appropriate driver would be assigned, but note that in my particular case - it's not a storage device, it is explicitly advertised as a 'processor device' from the target when a SCSI Inquiry is run on the device in question.  Again, this is done successfully on the HP-UX 11.3i systemA (with the scsi inquiry run against /dev/pt/pt2 and /ev/pt/pt3), but not on systemB as no entries appear (either after reboot or after running ioscan)

 

The ultimate goal is to make this seamless (and invisble) to the customer running their application, so telling them to run various 'mksf -P' commands is more of a last resort...

 

jerry

heymanj
Occasional Contributor

Re: HP-UX 11.3i passthru directory (/dev/pt)

From the previously mentioned White Paper:

 

"Array controller and other device file naming convention


Any device which is not claimed by a class driver is bound by default to the pass-through driver: esctl. This is the case for array controller devices. The device special name format for these devices is:


• /dev/pt/pt<instance>


For example if the system discovers 3 array controllers and assigned them instance numbers: 0, 10 and 12 respectively, it will automatically create the following device special files for these devices: /dev/pt/pt0, /dev/pt/pt10 and /dev/pt/pt12."

 

Since our device does not respond to Inquiry page 0x83 - we are counting on the above defined behavior.  Unfortunately, as I've said before, it works on one system but not another - both running HPUX 11.3i, though not necessarily an identical installation.