[COFF] non-volatile main memory (NVMM)

[COFF] non-volatile main memory (NVMM)

[gdmr]

Seen on one of our local "seminars" lists recently...

> Emerging hardware, such as non-volatile main memory (NVMM) [...]
> changes the way system software should be designed and implemented,
> because they are not just an enhanced version of existing devices,
> but provide new qualitative features and software interfaces.

Core store, mutter, mutter.

We used to regularly restart machines which had been turned off for a 
while, and they would happily pick up where they left off.  One PDP-8 was 
happy to resume after several years of idleness.

Sorry, had to send that, mutter...
-- 
George D M Ross MSc PhD CEng MBCS CITP
University of Edinburgh, School of Informatics,
Appleton Tower, 11 Crichton Street, Edinburgh, Scotland, EH8 9LE
Mail: gdmr at inf.ed.ac.uk   Voice: 0131 650 5147 
PGP: 1024D/AD758CC5  B91E D430 1E0D 5883 EF6A  426C B676 5C2B AD75 8CC5

The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

[COFF] non-volatile main memory (NVMM)

[david]

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> On Feb 20, 2020, at 3:54 AM, George Ross <gdmr at inf.ed.ac.uk> wrote:
> 
> Core store, mutter, mutter.
> 
> We used to regularly restart machines which had been turned off for a 
> while, and they would happily pick up where they left off.  One PDP-8 was 
> happy to resume after several years of idleness.
> 
> Sorry, had to send that, mutter…

So a story about core memory.
I was working with a group and had just finished bring up of a new system. It was running the diagnostics when someone in shipping turned off the hardware. No disk so no risk of breaking something like that (ah those were the days). Anyway they pack the machine and deliver it to the customer (name lost to the mists of time) who gets it set up and then powered on.

It resumes the diagnostic. The customer was amazed that the machine would perform a diagnostic on power up. Though that was the most wonderful idea.

	David

[COFF] non-volatile main memory (NVMM)

[dave]

On Thu, 20 Feb 2020, George Ross wrote:

> We used to regularly restart machines which had been turned off for a 
> while, and they would happily pick up where they left off.  One PDP-8 
> was happy to resume after several years of idleness.

There was a story posted to Usenet yonks ago about a minicomputer (PDP-8?) 
being used for nuclear testing.  The last test involved the box inside a 
truck, parked on top of the hole.  Truck flies up into the air, but the 
core memory survived intact, was retrieved, and plugged into another box 
and all the data read out.  Try doing *that* with solid-state memory :-)

-- Dave

[COFF] non-volatile main memory (NVMM)

[stewart]

So at the old MIT Architecture Machine (predecessor of the Media lab) circa 1975/6 we had Interdata 7/32 
minicomputers running the home-grown Magic 6 OS.

These machines had core memory, and there was a microcode bug that under certain circumstances (happily rare) you could get into an infinite loop taking interrupts or faults of some sort.

Due to the core, this condition could not be cleared by the reset switch or even turning off the power.  IIRC the only way to clear it was to unplug the core memory board while the power was on.

-Larry

> On 2020, Feb 20, at 3:39 PM, Dave Horsfall <dave at horsfall.org> wrote:
> 
> On Thu, 20 Feb 2020, George Ross wrote:
> 
>> We used to regularly restart machines which had been turned off for a while, and they would happily pick up where they left off.  One PDP-8 was happy to resume after several years of idleness.
> 
> There was a story posted to Usenet yonks ago about a minicomputer (PDP-8?) being used for nuclear testing.  The last test involved the box inside a truck, parked on top of the hole.  Truck flies up into the air, but the core memory survived intact, was retrieved, and plugged into another box and all the data read out.  Try doing *that* with solid-state memory :-)
> 
> -- Dave
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