EPROMs only keep memory 20 years!

[Bill]

It seems the data retention time for an EPROM memory is only 20 years....
http://www.st.com/stonline/products/families/memories/eprom/epromfaq.htm

And when these EPROMS fail, they will "bit flip" (changing a 0 to a 1 or a 1
to a 0)...
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41262/1/09-9.pdf

So what about all those vehicles on the road manufactured in the 80's with
EPROMS in the engine computers?

What else is still out there?

 

[Tzortzakakis Dimitrios]

It seems the data retention time for an EPROM memory is only 20 years....
http://www.st.com/stonline/products/families/memories/eprom/epromfaq.htm

And when these EPROMS fail, they will "bit flip" (changing a 0 to a 1 or a
1 to a 0)...
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41262/1/09-9.pdf

So what about all those vehicles on the road manufactured in the 80's with
EPROMS in the engine computers?

What else is still out there?

Only 50 erasing/programming cycles? Probably all '80s cars will be scrapped
before their EPROMs fail, there are hardly any left in Iraklion (180,000
residents). 20 years is an estimate, not a death sentence.

 

[Adrian C]

So what about all those vehicles on the road manufactured in the 80's with
EPROMS in the engine computers?

What else is still out there?

Cars with mask programmed ROM's. No issue with those.

Besides, it's all the other parts of 80's cars which will probably
rot/fail/explode/smoke/melt first. That is if you can afford to put gas
in some of them.

 

[James Sweet]

It seems the data retention time for an EPROM memory is only 20 years....
http://www.st.com/stonline/products/families/memories/eprom/epromfaq.htm

And when these EPROMS fail, they will "bit flip" (changing a 0 to a 1 or a 1
to a 0)...
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41262/1/09-9.pdf

So what about all those vehicles on the road manufactured in the 80's with
EPROMS in the engine computers?

What else is still out there?

The 20 year value is likely quoted minimum under worst case conditions.
I have a number of arcade games from the mid 70s to early 80s that are
almost all still running the original EPROMs, a few of them are more
than 30 years old.

 

[Andrew Gabriel]

The 20 year value is likely quoted minimum under worst case conditions.
I have a number of arcade games from the mid 70s to early 80s that are
almost all still running the original EPROMs, a few of them are more
than 30 years old.

I have an almost 30 year old minicomputer, which has lots of EPROMs
on things like peripheral controllers and the microprocessor system
controller (all 6800's), and they're all fine.

One thing that I recall killing a 10 year old EPROM was taking a photo
of the system -- the flash set a few bits. Best to make sure you have
metalic stickers over the EPROM windows. We used to use the write
protect stickers intended for 5.25" floppy disks, though you might
struggle to find those now.

 

[Tzortzakakis Dimitrios]

I have an almost 30 year old minicomputer, which has lots of EPROMs
on things like peripheral controllers and the microprocessor system
controller (all 6800's), and they're all fine.

One thing that I recall killing a 10 year old EPROM was taking a photo
of the system -- the flash set a few bits. Best to make sure you have
metalic stickers over the EPROM windows. We used to use the write
protect stickers intended for 5.25" floppy disks, though you might
struggle to find those now.

I remember those stickers! I also remember how my friends punched another
hole on 5 1/4 " floppies, to make them double-sided, for their commodore 64
drives.

 

[life imitates life]

I have an almost 30 year old minicomputer, which has lots of EPROMs
on things like peripheral controllers and the microprocessor system
controller (all 6800's), and they're all fine.

One thing that I recall killing a 10 year old EPROM was taking a photo
of the system -- the flash set a few bits. Best to make sure you have
metalic stickers over the EPROM windows. We used to use the write
protect stickers intended for 5.25" floppy disks, though you might
struggle to find those now.

The entire upright video game industry would also differ with this
claim. They all still work fine as well. Just keep the UV light out,
and you're good to go.

 

[James Sweet]

I have an almost 30 year old minicomputer, which has lots of EPROMs
on things like peripheral controllers and the microprocessor system
controller (all 6800's), and they're all fine.

One thing that I recall killing a 10 year old EPROM was taking a photo
of the system -- the flash set a few bits. Best to make sure you have
metalic stickers over the EPROM windows. We used to use the write
protect stickers intended for 5.25" floppy disks, though you might
struggle to find those now.

I have backups of most of the EPROMS in the old stuff I have, though I
do have a few ancient computers and peripherals I should do that to.

 

[James Sweet]

The entire upright video game industry would also differ with this
claim. They all still work fine as well. Just keep the UV light out,
and you're good to go.

All the ones I have came with stickers over the EPROM windows to both
protect them and identify the ROM position and software version.

Modern games tend to use mask ROM or flash memory with the bulk of the
data stored on conventional hard drives.

 

[krw]

I remember those stickers! I also remember how my friends punched another
hole on 5 1/4 " floppies, to make them double-sided, for their commodore 64
drives.

Which was a stupid thing to do. The sieve's liner cleaned the disc.
Flipping them over reversed the rotation causing the crud to be swept
out of the liner back under the head.

 

[life imitates life]

All the ones I have came with stickers over the EPROM windows to both
protect them and identify the ROM position and software version.

Of course. That is the way the industry managed ROMs then, and for a
long time until different, newer memory types emerged.

Modern games tend to use mask ROM or flash memory with the bulk of the
data stored on conventional hard drives.

Are you still talking about upright arcade games?

 

[Bill]

I know that in the 80s "we" designed some spacecraft computers that, in
flight, were expected to use "fuse link" type proms. The horror story
about they was that the fuse link could "grow back." I've been out of
the business since 1985 or so; I have no idea how these problems were
resolved.

The Hubble Space Telescope likely had some of those PROMs.

EPROMs were erased with UV light. One can only assume that radiation
(especially gamma and xray) would "clear" them.

I didn't check you link but I don't understand "bit flip." I understand
how the burried charge would dissipate and some cells go back to the
original, un-programmed, state (whether 1 or 0) but turning some 1's to
0's and some 0's to 1's in the same chip goes beyond the physics of the
devices as I understand it.

The above link is a NASA link. Also the paper mentions heat as being a
factor with EPROM memory retention failure. A vehicle, especially those in
hot climates, would be exposed to more heat than an indoor arcade game.

 

[daestrom]

Which was a stupid thing to do. The sieve's liner cleaned the disc.
Flipping them over reversed the rotation causing the crud to be swept
out of the liner back under the head.

When the practice was common, that argument and many others surfaced on
both sides (SD disks were just DD that failed on one side was another
common argument)

But that ship has long since sailed....

daestrom

 

[daestrom]

I have backups of most of the EPROMS in the old stuff I have, though I
do have a few ancient computers and peripherals I should do that to.

At work we still have a few 'Graphic Display Terminals' from about
85-86. A few years ago we pulled all the EPROMS and read them. Also
bought a bunch of the chips (they were getting scarce).

After re-installing the originals, we still haven't had any failures.
Next year, if the budget holds, we'll be ditching them for good. If
they make that, it will be 25 years without any failures (although we
have had to rebuild several power supplies )

daestrom

 

[life imitates life]

At work we still have a few 'Graphic Display Terminals' from about
85-86. A few years ago we pulled all the EPROMS and read them. Also
bought a bunch of the chips (they were getting scarce).

After re-installing the originals, we still haven't had any failures.
Next year, if the budget holds, we'll be ditching them for good. If
they make that, it will be 25 years without any failures (although we
have had to rebuild several power supplies )

daestrom

I still have a green phosphor (Ball)Hercules 720x480? monochrome
vector display. Nice for CAD on a 286. Runs on 12V and a
monochrome graphics card. It would be cool if there was a PCI to ISA
card adapter, then I could run it as a second display.

 

[James Sweet]

Of course. That is the way the industry managed ROMs then, and for a
long time until different, newer memory types emerged.

Are you still talking about upright arcade games?

Yes, I collect them.

 

[James Sweet]

I still have a green phosphor (Ball)Hercules 720x480? monochrome
vector display. Nice for CAD on a 286. Runs on 12V and a
monochrome graphics card. It would be cool if there was a PCI to ISA
card adapter, then I could run it as a second display.

If it's a vector display, there is no fixed resolution, it depends on
the capabilities of the vector generator hardware in the display adapter.

There is such thing as a PCI to ISA adapter
http://www.costronic.com/Ev71p.htm but drivers would likely be an issue.

 

[Mycelium]

Yes, I collect them.

That's kind of silly. I collect the Mame emulator and have over 6800
games I can play, and it is the exact same game(s).

I would never pay money for something so old, and so riffled with ripe
for failure electrolytics.

 

[life imitates life]

There is such thing as a PCI to ISA adapter
http://www.costronic.com/Ev71p.htm but drivers would likely be an issue.

I think the last OS that has monochrome driver setups even in it was
Windows 95. I think the NT releases had it. I doubt windows 2000 did.

Sad. Linux, IIRC will run the monochrome cards though.

 

[life imitates life]

If it's a vector display, there is no fixed resolution,

It had a resolution that was the result of the array the video card fed
it. Hercules and most monochrome cards would put out 640x400 or 640x480,
and this one would do 720x480.