SFF-8087 is internal and unshielded whereas SFF-8088 is external Shielded . 

 

If we are only talking internal vs external, then why does the 8087 have 36 pin vs 8088 having 26 pins? 

 

Why don't these have the same pins if one is just shielded for external and the other one is unshielded and internal? 

 

Thanks. 

 

 

Does anyone use SFF-8087 for external too connection? What exactly is so damaging if you have 2 PC next to each other and you have them going right over into another computer case next or behind your unraid server. 

 

The 8087 seem to be like more than 1/2 the price as the external shielded 8088. Do these external vs internal rules need to be followed when the 2 PC cases are so close to each other that they are practically in the same case? 

 

Thanks. 

What rules?

I think there is no problem if you also use the same power source from the case where the controller sits in.

If the PC cases use a PSU each, there might be potential differences that can damage your controller.

(unless the data link is galvanically isolated)

 

Edit:

Just saw, @ken-ji is using an external enclosure.

Maybe he can go more into detail?

Edited May 8, 20179 yr by Fireball3

The controllers all use differential signalling so there is no issue with them running from different power supplies

Sent from my LG-D852 using Tapatalk

I've had an Atto ExpressRAID R380 controller in an Apple Xserve connected to a Supermicro 24-bay SAS JBOD chassis running for years.  The JBOD chassis has its own power supply, and uses slot adapters to get from external to internal SAS cable connections. 

 

The only "rule" I concern myself with is that all my power connections are properly grounded, which means testing the IEC connection cables, as some of them are faulty even from new.

 

Well, I'm using SFF-8644 to SFF-8088 cables (HBA->Enclosure)

 

AFAIK regarding the OP, its just a matter how much you value the data travelling down the wire.

SFF-8087 is unshielded and meant for internal case RF noise, which is minimized by the fact that the parallel cables tend to be short runs.

SFF-8088 is shielded and meant for external RF noise, shielding takes care of the issue.

Additionally, SFF-8087 doesn't exactly lock in place and could get disconnected with a slight tug. non trivial force is necessary to unplug SFF-8088 (and the 8644)

 

If your two cases are side by side, I would use SFF-8087 cables only if they are short enough (i believe 1m max for SATA devices on those cables) and they are impossible be moved apart ie rack mounted. Otherwise, SFF-8088 is for the best.