topic Re: diff between /dev/fcdX and /dev/tdX in Operating System - HP-UX

diff between /dev/fcdX and /dev/tdX

Kuntal Gupta — Thu, 10 Feb 2011 05:49:09 GMT

Dear all,

Would any body pls brief the diff between:

1) /dev/fcdX and /dev/tdX

2)"Fibre Channel to Storage" and HBA

Regards...

Kuntal

Re: diff between /dev/fcdX and /dev/tdX

Torsten. — Thu, 10 Feb 2011 06:36:03 GMT

Different models of FC cards will be related to different drivers and different drivers will create different device files (e.g. td0 and fcd0).

The second question is not clear ... ?

Re: diff between /dev/fcdX and /dev/tdX

Manix — Thu, 10 Feb 2011 11:30:53 GMT

Different fiber channel models supports different drivers like tachyon & fc and hence they have different device files, depends on the cards model.

Re: diff between /dev/fcdX and /dev/tdX

Torsten. — Thu, 10 Feb 2011 11:45:39 GMT

Manix, do you want to say anything different compared to my post?

;-)

However look at this ioscan output:

fc 0 0/3/1/0 td CLAIMED INTERFACE HP Tachyon XL2 Fibre Channel Mass Storage Adapter
/dev/td0

The driver column says "td".

And now:

fc 0 0/4/1/0 fcd CLAIMED INTERFACE HP AB379-60101 4Gb Dual Port PCI/PCI-X Fibre Channel Adapter (FC Port 1)
/dev/fcd0

the driver column says "fcd".

And now another different card:

fc 0 40/0/2/0/0/0/0/4/0/0/0 fclp CLAIMED INTERFACE HP AD222-60001 PCIe Fibre Channel 2-port 4Gb FC/2-port 1000B-T Combo Adapter
/dev/fclp0

Oh, a new driver: "fclp".

So you can see, each different driver creates different device files.

Re: diff between /dev/fcdX and /dev/tdX

Alzhy — Thu, 10 Feb 2011 16:37:08 GMT

/dev/td devices are OLDER Tachyon (the chip) based FC HBAs (from the old Lucent spinoff?) They go only up to a max of 2Gbps. And are FC only cards.

/dev/fcd are QLogic based cards IIRC. They are faster and available in PCI-X and PCIe slot factors and can go 4Gbps+ and can be combo'ed with Gigabit ports on the same HBAs.

fcmsutil can be used to manage both cards.
fcdutil works exclusively on fcd HBAs.