topic Re: What are maximum scsi cable lengths? in General

What are maximum scsi cable lengths?

James Brand — Fri, 18 Oct 2002 18:13:15 GMT

We have D, K, and N class servers with HP scsi interfaces to EMC cabinets. We need to know the scsi specifications for these adapters. xstm doesn't show much, ioscan gives the following results:
D class: "Fast wide"
K class: "Fast wide"
N class: "Fast wide differential"

Are these 20MB or 40MB scsi interfaces, and what are the maximum cable lenghts allowed?

Re: What are maximum scsi cable lengths?

A. Clay Stephenson — Fri, 18 Oct 2002 18:21:25 GMT

These are Fast wide differential SCSI but more importantly they are High-Voltage Differential SCSI. The D's and K's only support HVD SCSI but the N box can support both LVD and HVD BUT NEVER via the same HBA. It oftens results in equipment death to mismatch these buses.

HVD SCSI is 20 MByte/s and supports cable lengths up to 25m.

LVD (sometimes called Ultra 2) SCSI can transfer at up to 80 Mbytes/s and supports a maximum bus length of 12m.

Re: What are maximum scsi cable lengths?

Eugeny Brychkov — Fri, 18 Oct 2002 18:41:18 GMT

Hello James,
good information source on general SCSI is at http://www.paralan.com/glos.html .
Eugeny

Re: What are maximum scsi cable lengths?

Gregory Fruth — Fri, 18 Oct 2002 18:58:41 GMT

Check out the table at:

http://www.scsita.org/terms/scsiterms.html

HTH

Re: What are maximum scsi cable lengths?

James Brand — Mon, 21 Oct 2002 14:40:51 GMT

Thanks to all!

Jim