Serial interfaces

John Foust jfoust at
Tue Jul 20 10:52:31 CDT 2010

At 09:15 AM 7/20/2010, Ethan Dicks wrote:
>I really do not like USB.  It takes hundreds of cycles and more to
>move a simple message, it's a host-based, not bi-directional design,
>and it's only available on somewhat newish kit.

What drives me crazy is the lack of debugging of the stack.  When
it's not working on contemporary Windows kit, there's no way I've
found to help understand what's not really working.  

This morning, I plugged a client's thumb drive into their laptop, and 
the logical drive seemed to disappear at random.  I switch connectors, 
thinking it's a wonky physical connector, no difference.  Just unreliable.  

Another stunner was that vmWare didn't support native USB on the host.
They're accomplishing thousands of other miracles, but can't virtualize
USB enough for me to connect a drive to a virtual appliance?
(I think this is fixed in last month's major release.)

I'm often trying to connect client hard drives to backup machines via 
USB-to-SATA/IDE adapters, and when the drive won't seem to wake-up
or show up, there's no way to debug where it is failing.  

I suspect some of the opacity is deeper in Windows at the logical 
Disk Management level, with layers of "Disk 1" numbering, logical drives 
and partitions and SCSI emulation, a registry that records every 
drive fingerprint ever connected to it (really), etc.

Last week, a client's thumb drives weren't being recognized.  I had to 
reinstall Windows.  I think Windows was failing at the very top layer, 
at the moment where a recognized device was known to be hard drive, 
but it couldn't show it as a logical drive.  

And yet so many built-in media-readers for CF/SD cards will show
logical drive letters to the OS when there's nothing inserted.
My desktop shows four.  Why?

- John

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