Proper SCSI Termination Procedure Needed

[JoskiRock]

Hi all,

I have a RapidFire SCSI II board that uses "Passive Termination". I have a Seagate "Hawk" HD that uses "Active Termination". In the RapidFire manual it says that I should disable the "Active Termination" on my HD, but then how to I terminate the HD? Do I have to get a "Passive Terminator" and put it on the end of the cable? Any help would be greatly appreciated. Also its a 50 pin HD.

Thanks

[motorollin]

JoskiRock wrote:
I have a RapidFire SCSI II board that uses "Passive Termination". I have a Seagate "Hawk" HD that uses "Active Termination". In the RapidFire manual it says that I should disable the "Active Termination" on my HD, but then how to I terminate the HD? Do I have to get a "Passive Terminator" and put it on the end of the cable?

Yes. The terminators must be of the same type on both ends (and compatible with the controller)

--
moto

[Zac67]

motorollin wrote:
Yes. The terminators must be of the same type on both ends

Says who? Sorry for being blunt, but that's the first time I hear about that. I've been happily mixing active (device internal) and passive (external) for ages - active strongly preferred of course. And I've seen some way complicated setups in their time.

Or is this a RapidFire specialty? :-?

[JoskiRock]

ok so if I use "Active" termination on the HD do I need to have the HD supply Termination power to the SCSI bus since the scsi card uses "Passive" termination? And if so, will this termination power hurt my scsi card?

[Kin-Hell]

The DKB RapidFire is a SCSI 1 board. Hence Passive Termination as this can only be used on SCSI 1. The problem with using Passive Termination is the Voltage fluctuations are not regulated from occuring in the first place & this is why Active Termination is a better choice. You could use active on this card if you wanted to, but why bother!? This SCSI card isn't even capable of DMA transfers, so using more than one hard drive/scsi device would be as slow as heck!
NEVER MIX PASSIVE & ACTIVE TERMINATION. Voltage drops/gains through passive termination will lead to data corruption along the length of the SCSI cable. It is also normal to terminate both Ends of the SCSI Bus.

[Gilloo]

Kin-Hell wrote:
The DKB RapidFire is a SCSI 1 board.

No, DKBRapidfire is a non DMA SCSI II board (fast scsi).
The external connector seems to be a 25 pin scsi 1, but internal connector is a true 50 pin fast scsi 2.

I don't use any terminator on mine (1 internal hdd + external cd300) and never had such problem.

[Kin-Hell]

Gilloo wrote:

Kin-Hell wrote:
The DKB RapidFire is a SCSI 1 board.

No, DKBRapidfire is a non DMA SCSI II board (fast scsi).
The external connector seems to be a 25 pin scsi 1, but internal connector is a true 50 pin fast scsi 2.

I don't use any terminator on mine (1 internal hdd + external cd300) and never had such problem.

Sure, the board lists as a SCSI 2 card. The only "2" about this card really is the fact it uses ZORRO II. Like I said earlier, the board isn't even DMA capable with more than 1 hard drive on it, which kinda wastes ones time having SCSI in the first place. Moreover, this card uses PASSIVE termination & "PASSIVE" termination is ONLY ever used on SCSI 1. I could be just as padantic & say it's a SCSI 1.5 card but however you look at it, it was a poor solution in it's time.

[Zac67]

Kin-Hell wrote:
"PASSIVE" termination is ONLY ever used on SCSI 1.

Actually, no.

(Slow) SCSI and Fast SCSI are OK when passively terminated, single ended Ultra requires active ones. Please note that SCSI-1, SCSI-2, SCSI-3 are bogus terms as they describe the standard version and not the actual type of interface used. There may (in theory) be a SCSI-3 drive that does async SCSI only. It's much more recommended to talk about 'Fast', 'Ultra', 'Ultra2', 'single ended', 'LVD', 'narrow', 'wide', etc.

Edit: SCSI-1 is actually valid for describing the speed as it only specifies one single sync mode.

[Kin-Hell]

Zac67 wrote:

Kin-Hell wrote:
"PASSIVE" termination is ONLY ever used on SCSI 1.

Actually, no.

(Slow) SCSI and Fast SCSI are OK when passively terminated, single ended Ultra requires active ones. Please note that SCSI-1, SCSI-2, SCSI-3 are bogus terms as they describe the standard version and not the actual type of interface used. There may (in theory) be a SCSI-3 drive that does async SCSI only. It's much more recommended to talk about 'Fast', 'Ultra', 'Ultra2', 'single ended', 'LVD', 'narrow', 'wide', etc.

Edit: SCSI-1 is actually valid for describing the speed as it only specifies one single sync mode.

Funny old world from the other side of the fence!

Google

Alot of the time, SCSI termination standards do not run by the book!