Front panel switches - what did they do?
spc at conman.org
Tue May 24 13:11:26 CDT 2016
It was thus said that the Great Swift Griggs once stated:
> On Tue, 24 May 2016, Charles Anthony wrote:
> > The data switches would be examined by the operating system during boot
> > to enable debugging (pause at certain points during boot, eg).
> I wish OS's still had something like this sometimes. Using a debugger over
> serial, there are times when I'd like to step through code or stop the
> whole kit-and-kaboodle. However, there are so many timers running in OS's
> these days a lot of the time that sort of thing causes major pain,
> especially with certain problematic drivers.
The Amiga has a minimal debugger embedded in the ROM that ran over the
serial port (9600 8n1). It would automatically become active when a Guru
Meditation (similar to a Unix kernel panic, or the Mac bomb, or the Windows
Blue Screen of Death) but you could get to it at other times as well (I
played around with it a bit). The debugger is *very* minimal (hex dumps of
memory and registers, you could modify memory and registers, resume, etc).
> > Some of the mainframes had hundreds and hundreds of lights, detailing
> > the internal state of the machine; mostly of interest to field
> > engineers.
> It probably still impressed the suits when they walked the data center.
> I've done data center tours with row after row of HP or Dell x86 servers
> and it's not much to look at.
The original Connection Machine had one LED per CPU (max 65,536). You
could get some pretty impressive visuals out of that one.
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