laptop 2.5" HDD IDE ribbon cable?

[Goi]

Hi,
I'm wondering if there are any differences between 2.5" HDD ribbon cables? Compared to their desktop variants, these cables are 2mm pitch instead of 2.54mm pitch, and 44pin rather than 40pin. However, I'm not sure if there are the 88 conductor cables for UDMA modes 4 and above? I looked at a laptop and it seems to use a 44 conductor cable since the plastic insulating layer of individual wires seem to be pretty thick.

Thanks!

 

[RebateMonger]

I can't find any reference to an 88-conductor IDE cable for laptops. The standard cable is 44-conductor, with the extra four wires used for 5V and 12V power/ground.

 

[Goi]

Yup I know the extra 4 wires is for power(5V actually, 12V isn't used for 2.5" drives), but I'm just wondering why they don't need double the conductors for UDMA4 and faster modes, while regular 3.5" drives require 80 conductor cables for UDMA4 and faster modes?

 

[Zepper]

The laptop cables are VERY short. The extra wires in the 80-wire cables are all grounds to provide a type of shielding and isolation - the shorter the cable the less the need for that. If they still use the mylar printed "cables" they could print a ground plane on the back side. It's been a while since I opened a notebook or laptop so I don't know what's common in there now.

.bh.

 

[Goi]

I see. I was wondering if it had something to do with the length...so is that the only reason? If I kept my IDE cables wto like 2-4" I could use 40 conductor cable as well? Also, how do people who use 2.5" PATA HDDs in SFF cases deal with this? I'd expect the cable to be quite a bit longer than in laptops.