topic Re: About single ended SCSI I device with SCSI II device. in Disk

About single ended SCSI I device with SCSI II device.

yyghp — Mon, 12 Jun 2006 14:37:41 GMT

If a single ended SCSI I device is put on a SCSI II bus cable with SCSI II devices, is that work? ( SCSI I device will be ignored or the entire SCSI bus will be disabled ? )
If it works, can the SCSI I device get better data transfer rate or the whole bus speed will be slowed down?
Thanks!

Re: About single ended SCSI I device with SCSI II device.

Jaime Bolanos Rojas. — Mon, 12 Jun 2006 14:41:24 GMT

yyghp!

The general rule is that scsi devices will work at the lowest speed of the device that is connected to.
If you are using a technology that works at a lower speed, the whole bus will work at that one speed.
There is not way to change it.

Regards,

jaime.

Re: About single ended SCSI I device with SCSI II device.

A. Clay Stephenson — Mon, 12 Jun 2006 14:43:25 GMT

See this link:

Your very question is answered.

http://www.datapro.net/techinfo/SCSI_FAQ.html#_Hlk410547597

Re: About single ended SCSI I device with SCSI II device.

Uwe Zessin — Mon, 12 Jun 2006 15:30:22 GMT

> If you are using a technology that works at a lower speed, the whole bus will work at that one speed.

Not generally true. Many components from the DEC/Compaq world do allow individual negotiations between the initiator and its targets.

Re: About single ended SCSI I device with SCSI II device.

Sandman! — Mon, 12 Jun 2006 19:04:09 GMT

SCSI devices are backward-compatible with one minor exception. HVD (high voltage differential) devices are incompatible with LVD (low voltage differential) and SE (single-ended) devices owing to the different voltages used. LVD is used only in SCSI-3 devices so that's not your worry.

LVD and SE devices are compatible with each other however the bus speed will drop down to the slowest link in the chain i.e. SE bus speed.

If you mix HVD and either LVD and/or SE devices then the chances are that the adapter or card will get damaged. Check out the URL below:

http://www.t10.org/

~cheers