alpha/127248: System crashes when many (7) serial port terminals (vt320-vt510) connected to the server via com to usb adapter and 2-usb hubs.

[Dieter]

[ -hardware@ list added to existing -alpha@ thread as this
doesn't seem to be alpha specific ]

> This is because USB is absolutely crap for this purpose.
> RS232 terminals, especially with long cables, can produce several kind
> of spikes and ground loops, which USB is very very sensitive about.

Many things about USB are crap (thanks, inthell), but if a USB to RS-232
bridge cannot handle normal spikes and ground loops, I'd blame the
bridge, not USB itself.  If the problem is spikes and ground loops
there is probably some RS-232 filter/isolator available to clean them
up.  There could be a bug in the bridge which needs a software workaround.
In any case the system shouldn't crash.

Are there specific make&model USB to RS-232 bridges that people
have had good luck with?

> My advise is to use a completely other technology to connect the terminals.
> A galvanic isolated USB device might work, but there are lot of PCI and
> Ethernet devices on the market which are more solid by design than USB.

The problem with PCI is the limited number of slots.  :-(

Ethernet could be a good solution for some applications, if you
can get the software to deal with it.  NFS is crap, *real* distributed
file systems handled devices transparently.  (thanks, Sun)

Does anyone make firewire to RS-232 bridges?