In article ,
William Sommerwerck wrote:

Does moving a scanner between my front and rear USB port really
require a driver reinstallation? WTF?

In theory, no, but that's the way it is.

That's almost entirely an operating-system issue... not USB per se.

It's a question of how does an application locate/identify/address a
specific USB peripheral.

USB has a tree hierarchy... controllers, hubs (possibly several layers
of them) and devices. Applications generally want to open a device
using a fixed, repeatable identifier. Depending on the OS and the
application, this identifier may be based on the bus topology (which
controller, hub chain, and port) or on the unique characteristics of
the device itself (model, manufacturer, type, serial number).

It sounds as if Windows is creating a unique, long-term identity for
the device based on both of these - the device itself, and the bus
topology to reach it - and that changing to a different port "orphans"
the identity. It might be Windows itself doing this, or the
manufacturer-supplied device driver.

Other operating systems (e.g. Linux) can assign a unique identity
based solely on the device's unique characteristics, assuming that it
has enough to make it unique (e.g. a real serial number), and the same
identity will be assigned to it no matter what port it's plugged into.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
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