Ok to leave slave HD cable connected with power off?

[Ron Reaugh]

Ok, all this talk of reflections on IDE cables has me confused - what should I
be avoiding to minimise reflections? having a drive attached without power?
having a single drive in the middle connector of an IDE cable with nothing at
the end?

A single drive always goes at the far end of the cable(as master).

 

[Rod Speed]

And you reckon *I'm* a tad radical!

That aint radical, stupid |-(

Incidentally, does the SATA spec make
such things simpler than the older ATA?

Yep, it allows for hot plugging in the formal standard.

ATA never has.

 

[Folkert Rienstra]

A single drive always goes at the far end of the cable

(as master).

Nonsense. Can be slave as well.

 

[Folkert Rienstra]

Having an open connector (i.e. infinite and discontinuous
impedance) at the end of a transmission line (i.e. the data
cable) produces strong reflections. The open connector
at a mid-point is not as a drastic change in impedance since
the transmission line continues on past it. Since any connector
creates some degree of impedance discontinuity, the fewer
connectors in the signal path the better - which is an argument
against slide-in hard drive trays. The question is really how
far do you think your hardware will let you stray from IDE
specs before there's a data error problem.

If you put a
removeable HD tray at the end of the cable with another HD
at the mid-point, the mid-point HD may have error problems
when the end tray is removed.

So you either do not remove it or replace it with another one.

If the removeable tray has the
only device on the channel, there probably won't be a problem.

If the removeable tray is at the mid-point, there probably won't
be a problem.

A removeable tray at the 'mid-point' is a potential problem when the tray
is of the kind that uses a small cable between drive and tray connectors.
That plus maybe an inch (or 2) in tracks and pin lengths on the tray
connector assemblies will add a substantial stub to the IDE cable (the
forbidden Y connection) and that may cause reflections by its own.

 

[Timothy Daniels]

"Folkert Rienstra" schreibt:

If you put a
removeable HD tray at the end of the cable with another HD
at the mid-point, the mid-point HD may have error problems
when the end tray is removed.

So you either do not remove it or replace it with another one.

[.....]
If the removeable tray is at the mid-point, there probably won't
be a problem.

A removeable tray at the 'mid-point' is a potential problem when the tray
is of the kind that uses a small cable between drive and tray connectors.
That plus maybe an inch (or 2) in tracks and pin lengths on the tray
connector assemblies will add a substantial stub to the IDE cable (the
forbidden Y connection) and that may cause reflections by its own.

Yup, the stub could be a reflection factory. Whether the timing
of the reflections over so short a distance would be a problem,
I have not idea. (That the timing of the reflections may be
significant may be the reason for the 18"/24" connector
positioning that is part of the IDE specs.) I guess the answer
for the removeable tray at the mid-point would be the same as
the answer for it being at the end - leave a tray with a HD in it
always plugged in to absorb the signal. But then the question
again arises about whether the tray (and the HD) must be powered
in order to absorb signal. If one wanted to limit the wear on a
removeable HD, the least risky way, IMHO, is to put the tray at
the end of the cable on a dedicated channel, even if it takes putting
in a PCI card with an added IDE controller to supply the extra
channel. Then removal of the tray wouldn't interfere with any
other device.

*TimDaniels*

 

[Less Entropy]

Mark:

I did a "StarTech DRW115ATA" search on Google Groups
and came up with this paragraph from a June 28, 2004,
message you posted to comp.sys.ibm.pc.hardware.storage.
Can you remember back that far?

I am considering the purchase of this product for my son,
and possibly, later on, for myself. I have been to StarTech's
WEB site. I have downloaded the manual for this product.

I have the impression that this product comes with "Swap Manager"
software that allows one to safely swap drives without powering
down the PC. Is that also your impression? Do you use this
so-called "hot swap" feature?

I have the impression that this software works with several
different Windows platforms including Win98SE and WinXP. If
you are using the "Swap Manger"--what OS are you using?

I'm also interested in your general experience with the product.
Does it seem to be worth the extra money? It has seemed to me
that it makes no sense to scrimp on something that "cradles"
a much more expensive hard drive. I hope to use this product
to house drives on the order of 250 GB.

Also, did you find a good place (price) to buy this product?

Finally, I didn't read this entire thread. How did it all
come out as far as having an unpowered drive--whether it sits
in the middle or at the end of the cable?

Sorry to pester you like this with "ancient history". I guess
that's one result of Google keeping so much old Usenet on the
WEB.

Thanks in advance for any help you can provide.

--Less