John-- Thanks for the suggestion. I finally had a chance to get to the system in question, It was the only one of many that exhibited the USB hang. I tried a reboot with the two USB disks disconnected. Everything worked. I plugged them in, and then did both "lsusb -v" and "lshw", and again, everything worked. Continuing my test: Reboot with both drives plugged in: all worked. Power off, wait 1 minute for everything to quiet down, power on: all worked. So, I can't reproduce the problem. I guess I have to blame cosmic rays or those nasty gremlins that inhabit our IC's. :-) Or is it related to the annoying spin-down and spin-up delay of external USB disks. I have issues with the spin-up delay on other CentOS platforms, and have managed to find a kludge to avoid it most of the time. Windows 10 seems to handle the delay well. Thanks for your idea. At least it led me to "lsusb -v". David At 05:33 PM 1/11/2018, Stephen John Smoogen wrote: >On 11 January 2018 at 20:23, david <david at daku.org> wrote: > > Folks > > > > I've been running lshw for years in both Centos 6 and Centos 7, yet just > > recently it started hanging. Neither a Control^C nor a "kill" of the > > process cured the hang; only a reboot. > > > >Is this just one system or a range of boxes? I just ran it on 2 >different ones running CentOS 7 and it worked fine there. If it is >just one particular hardware then look through the lshw man page and >try the versions of something like > >lshw -disable usb > >to see if it still happens. [It might require other tests also.] > > > > When I run it by hand from the command line, it displays stuff on the next > > line overwriting it with things like PCI, USB. And USB is the last thing I > > see. A Control-C does not unlock it. > > > > I am running lshw-B.02.18-7.el7.x86_64. The CPU is an Intel I7-3770K, > > running CentOS 7.4.1708 > > > > Is there any idea? Is there some alternate program that could list the > > hardware? > > > > Thanks > > > > David > >