Why do we have to keep rebooting things?
 

Of course there is always the multiple computer approach as used in aviation
where several systems work together and the moment one of these disagrees
its voted off and rebooted.
Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Paul D Smith" wrote in message
...
" wrote in message
...
Everything from satellite receivers to computers seems to need
unplugging from the mains so often and plugging back in. How come? Why
don't they make these things so that when they're incapable of doing
their job they just automatically reboot? Couldn't satellite receivers
(for instance) just run some sort of self-check routine in the
background and if it fails do a reboot? (and come back on the same
channel of course?).

Bill

You need to talk to some telecoms people. Telecoms require around 6-9s
reliability (i.e. dial-tone 99.9999% of the time - work out how many
seconds a year you can be "down").

Actually this is incredibly difficult using modern software because as
others have said, there is just so much of it and it can go wrong in so
may ways. For example consider the following code...

if (it's monday)
{
if (coronation street is on)
{
record it (1)
}
else
{
wait... (2)
}
else if (eastenders is on)
{
record it (3)
}
else
{
do something else (4)
}

There are 4 different blocks of "code" to test. Now software has 1000s of
such blocks and unlike in this case, they are often not independent.
Think perhaps of some code which does something if Coronation Street is
on, or East Enders, or both. You might think that these would be
independent but the programs are on different MUXs so two tuning
operations not one, and what if you're watching a third Mux? Oh, and you
only have one hard disk to record onto so the two recordings have to
share - you get the idea!

So for something like a PVR, if things do go wrong it's far better to
leave the smartest device in the room (normally), i.e. the owner to decide
what to do next rather than take a guess which might be totally the wrong
thing to do.

For example if my PVR locks up, as it has done occasionally, I never
reboot until after the "thing it should be recording" has finished.
Sometimes it makes no difference but sometimes it actually is recording
even though it's not responding to commands.

Of course with telecoms there isn't that luxury but then we would be
talking of powerful boxes costing a large amount of money and the cost of
specialist hardware and the like can be justified.

So, all down to bangs per buck. If all you want is something that does
all that a video recorder can then fine, but PVRs do far, far, more and
for far less cost these days - but you get what you pay for.

Paul DS

Why do we have to keep rebooting things?
 

In message , Brian Gaff
writes
So Clive Sinclairs claim that a nuclear power station could run on a zx81 is
a little irrisponsible then.

The ZX81 was very reliable - provided you raised it a little by standing
it on a book, so that the RAM pack (plugged in at the back) dangled in
the air. One day, all nuclear power stations will be controlled this
way.
--
Ian

Why do we have to keep rebooting things?
 

In article ,
Brian Gaff wrote:

So Clive Sinclairs claim that a nuclear power station could run on a zx81 is
a little irrisponsible then.

A lie perhaps, but not very irresponsible since no-one in a position
to use one for that purpose would actually believe him.

-- Richard

Why do we have to keep rebooting things?
 

In article ,
Ian Jackson wrote:

The ZX81 was very reliable - provided you raised it a little by standing
it on a book, so that the RAM pack (plugged in at the back) dangled in
the air. One day, all nuclear power stations will be controlled this
way.

Unfortunately by then physical books will be a rare commodity. Does
it work if you stand it on a Kindle instead?

-- Richard

Why do we have to keep rebooting things?
 

In article ,
Brian Gaff wrote:

Of course there is always the multiple computer approach as used in aviation
where several systems work together and the moment one of these disagrees
its voted off and rebooted.

Almost all the errors that cause your gadgets to reboot - and probably
most of the ones that cause planes to crash - are software errors, so
as well as several computers you need several independently-written
programs that do the same task, otherwise they will all get it wrong
together.

-- Richard

Why do we have to keep rebooting things?
 

" wrote in message
...
Everything from satellite receivers to computers seems to need
unplugging from the mains so often and plugging back in. How come? Why
don't they make these things so that when they're incapable of doing
their job they just automatically reboot? Couldn't satellite receivers
(for instance) just run some sort of self-check routine in the
background and if it fails do a reboot? (and come back on the same
channel of course?).



Why don't they just admit defeat and stick a reset button on the remote
control (IIRC didn't Nokia or have something similar back in the Ondigital
days?) a least it would save grovelling around on one's knees trying to
unplug the mains.

Why do we have to keep rebooting things?
 

"brightside S9" wrote in message
...
On Tue, 28 Sep 2010 10:33:38 +0100, "Ivan"
wrote:


" wrote in message
...
Everything from satellite receivers to computers seems to need
unplugging from the mains so often and plugging back in. How come? Why
don't they make these things so that when they're incapable of doing
their job they just automatically reboot? Couldn't satellite receivers
(for instance) just run some sort of self-check routine in the
background and if it fails do a reboot? (and come back on the same
channel of course?).



Why don't they just admit defeat and stick a reset button on the remote
control (IIRC didn't Nokia or have something similar back in the Ondigital
days?) a least it would save grovelling around on one's knees trying to
unplug the mains.

Buy a radio controlled 13 amp plug cum socket. Though the remote
control can have undocumented feature(s).


Ten to one the remotely controlled 13 amp plug/socket would crash and
without doubt in the 'off' condition!

Why do we have to keep rebooting things?
 

On 28 Sep, 09:28, bugbear wrote:
They put a lot of effort into making the EMS boot up nearly
instantaneously, and rebooted it (from a simple timer)
every couple of seconds!

Many years ago I designed a 'beacon keyer' for unattended operation at
a transmitter site; I really didn't want it to require a manual
reboot! So I connected the *reset* pin of the CPU (a Z80) to the
output of a divider off the master clock, which caused it to be reset
*tens of times per second*. Another possible source of instability is
corrupted RAM, so it had none: the only read/write storage in the
whole machine was the Z80's registers (around 48 bytes in all) -
fortunately they don't get cleared by a reset. It only once required
attention in several years of operation, when the crystal oscillator
failed.

Richard.
http://www.rtrussell.co.uk/

Why do we have to keep rebooting things?
 

"Ivan" wrote in message
...

"brightside S9" wrote in message
...
On Tue, 28 Sep 2010 10:33:38 +0100, "Ivan"
wrote:


" wrote in message
...
Everything from satellite receivers to computers seems to need
unplugging from the mains so often and plugging back in. How come? Why
don't they make these things so that when they're incapable of doing
their job they just automatically reboot? Couldn't satellite receivers
(for instance) just run some sort of self-check routine in the
background and if it fails do a reboot? (and come back on the same
channel of course?).



Why don't they just admit defeat and stick a reset button on the remote
control (IIRC didn't Nokia or have something similar back in the
Ondigital
days?) a least it would save grovelling around on one's knees trying to
unplug the mains.

Buy a radio controlled 13 amp plug cum socket. Though the remote
control can have undocumented feature(s).


Ten to one the remotely controlled 13 amp plug/socket would crash and
without doubt in the 'off' condition!






I worked for a manufacturer of a CNC mill set up.
They had a Emergency Stop that used the software .

I thought that was silly, no one listened.

A customer had a fault one day and the tool started going through the mill
table. They hit the Stop and nothing it kept on milling.

Then they found the main switch and turned it off, lost the programme,
everything off.

They then had to retrofit a simple power Emergency stop an all past and
future production.

Much safer.

Gary

Why do we have to keep rebooting things?
 

On Mon, 27 Sep 2010 17:51:51 -0700 (PDT), "
wrote:

Everything from satellite receivers to computers seems to need
unplugging from the mains so often and plugging back in. How come? Why
don't they make these things so that when they're incapable of doing
their job they just automatically reboot?

I switch everything off every night. I never have to reboot. ;)


--
AnthonyL