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On 6/25/2011 6:28, Jim Holsenback wrote:
> I worked on a piece of avionics gear that was used to identify submarine
> acoustic signatures ... it was loaded with mag core memory
I knew someone who worked on modern military helicopters, at least some of
which also have mag core memory. The thing is, it's non-volatile. You can
lose power without wiping out your mission or having to reboot or whatever.
When I was in college, I was working on a big assembly program on a
mainframe. 20 minutes into a 30 minute compile, all the lights go out. I
think "Well, so much for getting this done before lunch." Three minutes
later, the lights come back on, I start getting messages on the terminal
about disks being inaccessible, and then ten minutes later I get "compile
completed." So, yeah, there was enough voltage in the capacitors to save
the registers out to memory when the power-fail interrupt came along.
--
Darren New, San Diego CA, USA (PST)
"Coding without comments is like
driving without turn signals."
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>>> Also: My dad has a Honeywell central heating system. WTF?
>>
>> Why WTF??
>
> That's like... that's like a company that manufactures motorbikes also
> manufacturing pianos!
>
> ...oh, wait...
>
It's rather a piano maker that also make motorbikes. There where Yamaha
pianos long before the first Yamaha bike...
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On 25/06/2011 06:44 PM, Darren New wrote:
> I knew someone who worked on modern military helicopters, at least some
> of which also have mag core memory. The thing is, it's non-volatile. You
> can lose power without wiping out your mission or having to reboot or
> whatever.
I wonder how well the power consumption of core compares to flash.
Because, let's face it, flash is available in densities that core will
never match.
Also, I was under the impression that core requires constant temperature
operating conditions, or you have to recalibrate it.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Am 25.06.2011 19:44, schrieb Darren New:
> I knew someone who worked on modern military helicopters, at least some
> of which also have mag core memory. The thing is, it's non-volatile. You
> can lose power without wiping out your mission or having to reboot or
> whatever.
Flash memory would do that, too. But I guess when the military does such
things, they know what they want. Robustness against gamma rays or EMP
or some such might be a reason.
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On 6/26/2011 3:07, clipka wrote:
> Am 25.06.2011 19:44, schrieb Darren New:
>> I knew someone who worked on modern military helicopters, at least some
>> of which also have mag core memory. The thing is, it's non-volatile. You
>> can lose power without wiping out your mission or having to reboot or
>> whatever.
>
> Flash memory would do that, too. But I guess when the military does such
> things, they know what they want. Robustness against gamma rays or EMP or
> some such might be a reason.
Well, to be fair, by "modern" I meant "not 1960's", I didn't necessarily
mean "2011". :-) This was... let's see... 1990 or so? So maybe they're
using flash now.
Another restriction is that you have to be able to actually erase the memory
completely, such as in the event of landing in enemy territory. I don't know
how well flash erases.
--
Darren New, San Diego CA, USA (PST)
"Coding without comments is like
driving without turn signals."
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Le 26/06/2011 20:37, Darren New nous fit lire :
> On 6/26/2011 3:07, clipka wrote:
>> Flash memory would do that, too. But I guess when the military does such
>> things, they know what they want. Robustness against gamma rays or EMP or
>> some such might be a reason.
>
> Well, to be fair, by "modern" I meant "not 1960's", I didn't necessarily
> mean "2011". :-) This was... let's see... 1990 or so? So maybe they're
> using flash now.
>
Flash have a limited number of write, not something you want to deal
with in a desert year long operation.
(military helicopters have such a long live time, mechanical maintenance
is ok on field, but electronic maintenance is always long, expensive &
tricky (i.e. not for the sergent)
> Another restriction is that you have to be able to actually erase the
> memory completely, such as in the event of landing in enemy territory. I
> don't know how well flash erases.
>
Usually a little explosive if all they need... as long as it is not
triggered by the EMP. If the information is really sensitive.
Usually it is not: the main target (or secondary ones) is just
coordinates for that mission. And nowadays, everyone has maps.
The Friend-or-Foe identifiers will be changed by the next day/hour, no
problem either.
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On 6/26/2011 11:51, Le_Forgeron wrote:
> Flash have a limited number of write, not something you want to deal
> with in a desert year long operation.
It's also easy to plug in and out, compared to core. :-)
>> Another restriction is that you have to be able to actually erase the
>> memory completely, such as in the event of landing in enemy territory. I
>> don't know how well flash erases.
>>
> Usually a little explosive if all they need...
I think the idea was you erase it when you park the vehicle, maybe? I was
under the impression they didn't want to actually destroy the thing, but
rather that this was a normal part of operations.
I wasn't sure what he was trying to erase, of course.
--
Darren New, San Diego CA, USA (PST)
"Coding without comments is like
driving without turn signals."
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Le 2011/06/26 06:07, clipka a écrit :
> Am 25.06.2011 19:44, schrieb Darren New:
>> I knew someone who worked on modern military helicopters, at least some
>> of which also have mag core memory. The thing is, it's non-volatile. You
>> can lose power without wiping out your mission or having to reboot or
>> whatever.
>
> Flash memory would do that, too. But I guess when the military does such
> things, they know what they want. Robustness against gamma rays or EMP
> or some such might be a reason.
Core against an EMP? An EMP can very easily whipe out any magnetic core
at an intensity that would not affect any consumer grade flash unit.
Then, you can have military grade hardened flash memory that's shielded
against such agressions.
As for gamma rays... a simple redudency system will do.
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On 6/25/2011 7:34 PM, Alain wrote:
> It's rather a piano maker that also make motorbikes. There where Yamaha
> pianos long before the first Yamaha bike...
But, is that the same Yamaha?
--
~Mike
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On 06/27/2011 09:51 AM, Mike Raiford wrote:
> On 6/25/2011 7:34 PM, Alain wrote:
>
>> It's rather a piano maker that also make motorbikes. There where Yamaha
>> pianos long before the first Yamaha bike...
>
> But, is that the same Yamaha?
>
yep ... same logo anyways
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