Re: Debian + PC with multi RS... port -> n x (text dumb t
On Sun, 14 Sep 1997, A. Paul Heely Jr. wrote:
> The backroom system has never gone down from a hardware failure. It has
> crashed/locked up for who knows what reason. I know that it
> should not happen but it can. The registers also have
> been known to lock up, more so than the backroom. If a register locks
> up there are other registers that can be used while the other is
> being re-booted. If the backroom system goes down and you are using
> just terminals then the whole operation is at a stand still until
> the system comes back up. You may say, but it only takes 5 minutes
> to do a complete shutdown and reboot, but this is 5 minutes that our
> customers have been standing around waiting for us. To them it seems
> like forever, and does not promote a very professional image.
>
> My main thought in favor of the 386's is that even if the backroom
> goes down, however remote, the operation that the customer sees is
> still functioning.
>
On 14 Sep 1997 John Hasler <john@dhh.gt.org> wrote:
> > Yes but a terminal does NOT go down unless broken,...
>
> In my experience terminals are no more reliable than pc's (pc's running
> Linux, that is).
>
> > ...while some of those 386 could go down.
>
> If one of the 386's goes down then only one of your lines is down. If you
> use terminals and your central machine goes down it takes all your lines
> with it.
>
> > ...why should it crash (provided you put a power supply backup of
> > course), I mean why more likely than those 386's?
>
> No more likely. I repeat: if the machine driving your terminals goes down,
> your whole system goes with it. If one of the 386's goes down, you've
> still got your other lines.
>
> John Hasler
> john@dhh.gt.org (John Hasler)
> Dancing Horse Hill
> Elmwood, WI
>
Yes, that's not a bad point, surviving machines in case of a crash...
provided the software on the 386's is designed not to necessarily send
everything immediately to the main dbase...
... but also PROVIDED there is no need to consult the main dbase,
which is much likely necessary if you have to translate a barcode into a
price + description to print + what else, or even before doing the sell
maybe just to look for something the customer wants and see if it is
available before walking some hundred meters looking for it... I think
nobody would think about replicating data on each of the 386's!
Having for sure surviving machines... would we have them in the end?
I mean, what scares me is all that ethernet running here and there, it
sounds more critical than a serial line (short or with a couple modems at
worst for the longest paths). What happens if it is the ethernet
connection that falls? (By the way, do _your_ 386's boot via ethernet or
do they have Linux on their own hard disk?) Isn't it much a weaker point
than only having to take care of one (or a few) Debian box(es) with
"strong" software? (What geometrical configuration have you ethernet
points, a bus?)
On Sun, 14 Sep 1997, A. Paul Heely Jr. wrote:
> I think the 386's offer more capabilities than a terminal alone.
> Our machines use a bar code reader, a credit card scanner, control
> when the cash drawer opens, print to a receipt only printer, and
> print to the invoice printer. I don't see how you would get this
> much functionality out of just a terminal.
>
What ports are these devices connected to?
Nicola Bernardelli <nbern@mail.protos.it>
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