Differential SCSI?

[Ronelle van Niekerk]

OK, someone is sending me a DLT library that I need to use to test some omnistorage stuff and he has said that I need to use a differential SCSI port and cable for this library.

Excuse my complete ignorance, but what is differential SCSI and how do I tell if I have a differential SCSI card installed on my L100 server?

P.S. This thread has been moevd from General to Tape Libraries and Drives. - Hp Forum moderator

[James Murtagh]

Hi Ronelle,

Its the type of signalling on the scsi bus. I normally go to this site for most scsi queries :

http://www.pcguide.com/ref/hdd/if/scsi/index.htm

Don't be put off by the PC guide bit, its well written. :-) For differential scsi see this section :

http://www.pcguide.com/ref/hdd/if/scsi/prot_Diff.htm

To find what you've got on your system you can use :

# ioscan -fnkC ext_bus

You'll probably see LVD (low voltage differential) scsi cards on the L1000.

cheers,

James.

[T G Manikandan]

One of the pages I have always bookmarked

http://fieldhome.net:9080/scsi_faq/scsifaq.html

[Ronelle van Niekerk]

Thanks guys but no LVD scsi cards in my ioscan:

Class I H/W Path Driver S/W State H/W Type Description
============================================================================
ext_bus 0 0/0/1/0 c720 CLAIMED INTERFACE SCSI C896 Fast W
ide Single-Ended
ext_bus 1 0/0/1/1 c720 CLAIMED INTERFACE SCSI C896 Ultra
Wide Single-Ended
ext_bus 2 0/0/2/0 c720 CLAIMED INTERFACE SCSI C875 Ultra
Wide Single-Ended
ext_bus 3 0/0/2/1 c720 CLAIMED INTERFACE SCSI C875 Ultra
Wide Single-Ended
ext_bus 4 0/4/0/0.8.0.255.0 fcpdev CLAIMED INTERFACE FCP Device Inter
face

Is there any way to use this library without getting another scsi card installed?

[Leif Halvarsson_2 · Accepted solution]

Hi,
Is your library a HVD or LVD (High or Low voltage differential). If HVD, you can't use it on your system. But, LVD devices is compatible with Single Ended (SE).

[Ronelle van Niekerk]

Damn!

It's a TL891 DLT Mini-Libaray

Interface: Fast Wide, Differential (HVD), SCSI-2.

[David Ruska]

The TL891 (with DLT7000 drives) only came in an HVD configuration. However, there were "interface kits" available that convered from HVD to SE SCSI, so the library could be connected to Proliant servers. The 113395-001 kit was used for 68HD connector HBAs, and the 113396-001 was ued for 68VHDCI connector HBAs.

FYI, the TL891 (a compaq product) was never integrated on HP-UX. The supported platforms were Alpha, Digital, and Proliant. Therefore, there are no guarantees that it will work on an HP-UX system if you did have the right HBA type (or the interface kit).

[Angus Crome]

Here is the output from an L2000 with two HVD PCI cards in it;

# ioscan -funC ext_bus
Class I H/W Path Driver S/W State H/W Type Description
=================================================================
ext_bus 0 0/0/1/0 c720 CLAIMED INTERFACE SCSI C896 Fast Wide Single-
Ended
ext_bus 1 0/0/1/1 c720 CLAIMED INTERFACE SCSI C896 Ultra Wide Single
-Ended
ext_bus 2 0/0/2/0 c720 CLAIMED INTERFACE SCSI C875 Ultra Wide Single
-Ended
ext_bus 3 0/0/2/1 c720 CLAIMED INTERFACE SCSI C875 Ultra Wide Single
-Ended
ext_bus 4 0/4/0/0 c720 CLAIMED INTERFACE SCSI C875 Fast Wide Differe
ntial
ext_bus 5 0/4/0/1 c720 CLAIMED INTERFACE SCSI C875 Fast Wide Differe
ntial
ext_bus 6 0/7/0/0 c720 CLAIMED INTERFACE SCSI C875 Fast Wide Differe
ntial
ext_bus 7 0/7/0/1 c720 CLAIMED INTERFACE SCSI C875 Fast Wide Differe
ntial

I believe you can buy them rather cheap from resellers and Channel partners. I use them to connect old 4 and 9Gb HVD Jamaica disks, but I used to use them to connect to my HVD DLT drives in an HP A4845A Library.