topic Re: SCSI-2 in Operating System - HP-UX

SCSI-2

Steve_3 — Tue, 23 Jan 2001 20:13:57 GMT

Trying to find if my hp server have any SCSI-2 controller.

thanks,
steve

Re: SCSI-2

paul courry — Tue, 23 Jan 2001 21:53:14 GMT

Take a look at the back. If you see any 68 pin connectors (Narrow SCSI such as C2490AM uses a 50 pin connector) or if you have a K class server (which has Fast Wide SCSI built in to the Core I/O board) then you have SCSI-2.

(Not knowing the SCSI classifications all that well, I assume you mean differential SCSI, such as would run a ST15150WD disc drive from Seagate).

An ioscan if Unix or a iomap if MPE will tell you if you have any Fast Wide SCSI boards installed. As I said K-class boxes have them in the Core I/O card. The L's and N's I just looked at don't *seem* to come preinstalled with them.

Hope this helps.

Re: SCSI-2

Michael Lampi — Wed, 24 Jan 2001 23:58:55 GMT

SCSI-2 refers to a particular set of protocol and signal definitions of the SCSI specifications.

SCSI-2 defines both narrow (50 pin) and wide (68 pins or more) buses.

SCSI-2 also defines the two signaling methodologies, single ended and differential.

SCSI-2 defines several other basic areas, such as asynchronous and synchronous data transfers, slow and fast data transfers, etc.

Updates to the SCSI definitions since the adoption of SCSI-2 include Ultra, Ultra-2 and Ultra-160 SCSI. These are all backward compatible in one way, shape or form with SCSI-2. However, due to basic electrical differences between single ended and SCSI-2 differential (also called high voltage differential), the latest Ultra-2 and Ultra-160 devices are not compatible with high voltage differential SCSI buses.

Since all HP systems since the dark ages have used SCSI controllers following the SCSI-2 specifications for disk and tape I/O, your HP system definitely has a SCSI-2 compatible controller, even if it also supports the latest Ultra-160 devices.

Be aware, however, if you connect an older SCSI-2 device to an Ultra-2 or Ultra-160 SCSI bus, then all devices on that bus will operate at a rate no faster than Ultra-1 speeds. Cable length limitations are also the same as for Ultra-1 systems. Of course, if all the devices on that bus are the slower SCSI-2 variety, then the cable limitations are the same as that of SCSI-2.