lvd drives.

[keysmia]

I have an IBM ultrastar 18.2 gig drive. I think it might be an lvd drive. I have it on the internal scsi bus of my 9600. Can this cause problems? or bus errors? I am using a granite digital 68pin to 50 adapter. The unit came with no documentation and the web site is unclear as to whether this is an lvd drive. Ibm ultrastar 18 zx drvs18v. If anyone knows please respond until I call Ibm. Thanks.

[ThomCat]

My understanding is that all LVD drives are backward compatible...in other words they will work fine with non-lvd scsi adapters, they just default to a non-lvd mode. Can anyone confirm?

I think if you're having bus errors that the fact that your drive may be lvd or not is likely not the cause. Are the -6042 errors? Lord knows I've seen my share of those.

[ThomCat]

I just realized something else reading your original post. In my many trials and tribulations with the black art of SCSI I once heard that 50 to 68 pin adapters might be a no-no, due to the fact that now possibly 18 pins of the 68 won't be terminated properly, depending on the adapter. I'm not real clear on this, but when I stopped using the adapter I had less problems. Can anyone elaborate on that potential problem?

[tld]

I've never had to do it, but I think you should be able to use it on a narrow buss with a 68x50 pin adapter no problem, and the adapter from Granite is about as good as you can get.

As far as LVD goes, I believe ThomCat is correct that drives will detect that they are not on an LVD buss and will operate in single ended (non-LVD) mode. Sometimes drives will have a jumper you can add that will force it into single ended operation. I use two 9GB Seagate Barracudas (which are LVD drives) on an ATTO scsi accellerator which is 68 pin but is not LVD. They had a jumper to force that mode so I used it. From what I've read however, I think they would have worked without it.

I'm no authority....ThomCats 'black art' reference is appropriate. Try searching various forums here for keywords like scsi, lvd, single ended etc....there's a ton of posts out there...you'll run into me on several of them http://www.digidesign.com/ubb/images/icons/smile.gif

Tom


[This message has been edited by tld (edited June 13, 2000).]

[keysmia]

Thanks for the replys. The drive is an lvd. I received it with no documentation and no jumpers. I called ibm and they told me what settings to use . I also reinitilized my boot drive and reinstalled everything. It seems to work fine now. My question now is. Now that the drive is being seen as a non lvd on the bus, will that hinder it's performance?

[E-an]

We have exactly the same drive as you... and for a while we ran it with a 50 to 68-pin adapted with no problems (that was using the default settings).

We only ran into problems getting it setup with a Adaptec 2940 SCSI card. Obviously we didnt need to the adapter (50-68) with this card but as you did we called IBM and it was setup quickly.

There are settings + instructions on the site you just have to look hard http://www.digidesign.com/ubb/images/icons/smile.gif http://www.storage.ibm.com/techsup/hddtech/table.htm
(thats all the drives they do linking to tech info + white papers + installation the lot!)

AFAIK the performance is changed but from what I remember there is a maximum transfer rate somewhere which is imposed but cant quite remember where I read it - any ideas anyone?