From: John Crane on 3 Feb 2010 10:33
"David L. Jones" <altzone(a)gmail.com> wrote in message
> Ingo Thies wrote:
>> Daniel Oliva wrote:
>>> I think flash memory is untouched unless you write/delete something
>>> there (ROM upgrade, install a new library, or write any other object
>>> to flash).
>>> The calculator does not write to flash for normal operation.
>>> No need to worry about that.
>> Hmm, I can't speak for the HP 48/50, but the manual of the Casio 5800
>> says that the variables and program data are stored in the flash
>> memory to be kept even if the battery is replaced. The manual doesn't
>> mention any auxiliary battery.
>> So the flash is actually used in normal operation, but the question is
>> how often it is used.
> Actually there is another question too.
> How long will program FLASH retain its contents?
> Hint - it's not "forever".
> Check out my Electronics Engineering Video Blog & Podcast:
I use Flash RAM in computer applications, and the manufacturer's specs say
data is guaranteed to be retained for 100 years.
From: Dueño de Monte on 4 Feb 2010 08:30
I have an HP48SX since 1991, and must of the data set there, are still
there with no troubles (almost 19 years), of course I have now an HP49
and HP50, that have a MUCH BETTER display and speed to process them.
So don´t worry, you´ll change the flash memory before it fail because
of its age.
From: John H Meyers on 4 Feb 2010 13:55
Surely there are different specs for different flash chips,
so one would need to know what part number is in each calculator,
to be able to find its particular specs.
The original HP49G is the oldest of this series having flash memory
for "ROM" and for "Port 2." Subsequent models have a different
architecture, and probably different flash chips as well.
Erase/rewrite cycles do "wear out" flash memories, eventually,
and probably some time period is also estimated for each chip's lifetime,
but I don't know any of the specs for any particular model or chip
(I dimly recall a suggestion of ten years for the old 49G).
The HP48SX and 48GX have no flash memory -- they have ROM and RAM,
as do their plug-in cards.
From: Dueño de Monte on 5 Feb 2010 04:39
So, my HP49g+ is from 2003 (7 years) with no troubles on the flash
From: val on 5 Feb 2010 04:50
John H Meyers a �crit le 04/02/2010 :
> The HP48SX and 48GX have no flash memory -- they have ROM and RAM,
> as do their plug-in cards.
> [r->] [OFF]
I bought a TDS 1Mb RAM card last summer and the programs are still in
the card even if the card was removed from the HP for more than 3
monthes. However, there is no battery holder on the card so I guess it
is flash memory (?). There is no switch as well.