2 things: round cables & what's the diff between LVD80 and LVD160 cables?

[Sir Fredrick]

I recently rounded my floppy cable with no problem, and I noticed that it made the cable a lot more flexible. I had an extra 50pin SCSI cable so I decided to be brave and round that too. Worked flawlessly, and again the dable was MUCH more flexible, and the stiffness had been a pain before.

I have an LVD80 and an LVD160 cable, and they look very similar. Is there actually a difference between the two? If not, I'd like to try rounding my LVD80 cable. But I'm not going to bother if it's going to make my drives run at LVD80 instead.

Rounding appears to be feasable, from what I can tell, the LVD80 cable is divided up into 3s. There's one wire that runs straight, and two others which wind around it, presumably for shielding and such. So as long as those 3 wires stay together, I don't think it'll matter if the cable is rounded.

 

[Hard_Boiled]

I could be wrong but I don't think that cable will drop you to Wide Ultra2(LVD 80, whatever). At this site they make no mention of any differences between LVD cables, but it makes me wonder why places would sell cables for 80 MB/s and 160 MB/s implementations.

 

[Odeen]

Sir Fredrick: Due to the the way LVD cable works, I'd advise you to NOT round it... it sends the signal and the negative signal on adjacent wires, and the two are subtracted, to get the interference experienced, then the interference is subtracted from the signal received (hence the moniker - Low Voltage Differential)

As far as LVD vs Ultra160, this is one of my pet peeves. Interface transfer rate does not matter as long as it's near the max speed for the drive(s) used.

For a SINGLE hard drive NO ONE needs over 40mb/sec. My Cheetah X15 and Atlas 10K II eke out 43 megs per second for like 1/10 of the drive for the 10K II, and 1/4 of the drive on the Cheetah - I'd be PERFECTLY CONTENT running either drive on an UltraWide feed.

As it stands, I have a 2940U2W, and both drives run at 80mb/sec. I could put them both on, say, a 39160, but that won't raise my HD tach scores, or my performance one yota. Heck, if you put a Barracuda or an Atlas IV on a 10mb/sec SCSI-2 adapter, you won't notice it much - the seek time will stay the same.

Alex.

P.S. - Go ahead and round your LVD80 cable.. back up your system, then try it. I'd like to know if anyone has actually had enough guts to do it and enough skill to succeed.

 

[Hard_Boiled]

You can buy rounded LVD cables, I think it should be okay.

 

[Odeen]

Hard_Boiled: ME WANT URL!!!

 

[borealiss]

i highly suggest you don't round lvd cables. they are adjacent for a reason, and not looped around one another or weaved into a rounded cable. i've had crosstalk occur with 2 lvd cables that were right next to one another in my system, and these were not rounded, just 2 cables next to one another. when i would separate the the cables by a couple of inches, my read/write errors would go away. but if you do decide to do this, send us pics!

 

[Sir Fredrick]

I have multiple drives on my LVD channel, so theoretical bandwidth does make a difference. Benching my two drives simultaneously on an LVD80 controller shows a bit of a performance hit when benching simultaneously, not so on the LVD160 controller.

I have access to two SCSI controllers, and one drive which has no important data on it. I don't want to completely ruin the LVD80 cable, so I'll just round the very last section of it first, I can always terminate before that if it's no good. I'll benchmark before and after to make sure there's no performance hit too. I'm not sure when I'll do this, so don't hold your breath guys, but I'll try to do it soon.

I don't think my other question has been answered though, are LVD80 and LVD160 cables the same?

 

[Hard_Boiled]

I've heard this place www.scsi-cables.com can make you a custom rounded cable. I don't see it anywhere on the page, but I'm pretty sure if you e-mail them or look around on their site you'll find there rounded cables. The appear to make all the cables to order anyways. www.cablemakers.com might also make custom rounded cables.

Fredrick, I think LVD80 and LVD160 cables are basically the same. Don't hold me to it, but I strongly doubt using a cable specifically marked LVD80 will drop your entire chain down to 80 MB/s.

 

[Sir Fredrick]

hard_boiled, the first site you linked to shows LVD80 cables with a different impedence, so they might very well not be compatible. I suppose I'll test that too.