"Jeff Richards" wrote in message
Your comments are confused.

And your's are any better?

There's no such thing, in SCSI or IDE, as a terminated or unterminated device.

Well, there is in the physical sense, as a device that provides the termination.

There's a device, a terminator, or no device.

The terminator is a cheap way of pretending some sort of device is connected,

Uh no. It is pretending that the cable is endless.

and it's important for SCSI mainly because of the cable lengths involved.

In part.
Without any termination a SCSI bus doesn't function at all, nomatter how short.

It doesn't really matter for IDE because the impact of an unterminated
connector on the signal quality (ringing, overshoot) is much less with the
shorter lengths involved,

In part.

and the IDE interface can cope with it.

No, it *can't*. It *could* when interface speeds were still (s)low and
the *interface* wasn't yet acting like a *bus*, ie a *transmission line*.
Changes were necessary to keep it working with the higher UDMA modes.
One of those came to be known as series termination.

But there is still a difference in signal quality between an IDE cable
with a device connected and one without.

An 'Inactive' IDE device is not particularly high resistance, and certainly
has an impact on signal quality compared with an open connector.

In comp.sys.ibm.pc.hardware.storage glee wrote:

But as I said a device at the end will not improve the
situation for the device in the middle in any way. It does not
matter whether it is an 40/40 or an 40/80 cable. IDE devices
just don't do any termination. That means that while inactive
the IDE device at the end will just be a very high resistance
digital input. No effect on electical echoes on the wires at all.

If you have a borderline broken device, then you may observe it
only working on the cable end. However if you have a correctly
working device it must work in both positions, regardless of
whether another device is present. (Disregarding the CS/jumpers
issue for the moment.)

Arno