[vcf-midatlantic] Good source for eproms?

[Chris Fala]

Oh, hey, somebody need an X-ray machine? Just see Dave! LOL

On Fri, May 27, 2016 at 11:46 AM, Dave McGuire via vcf-midatlantic <
vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:

> On 05/27/2016 11:02 AM, Herb Johnson via vcf-midatlantic wrote:
> >>   They can be erased with X-rays.  EPROMs were originally designed to be
> >> erased that way.  There are problems with that approach, however. (hence
> >> the move to UV).
> >
> > The notion that one can plop non-quartz PROMs under an X-ray and erase
> > them, has been mentioned here, and elsewhere for decades,  as a "could
> > be done". But I'm not aware this has been, or is, any sort of common
> > practice, much less an established procedure. I'm aware of 'theory', I
> > know physics. I'm talking accepted practice.
>
>   There is no accepted practice, but you and I know theory and physics,
> so we know it's possible.  We've also read the documentation you
> referenced below and know it had been done, and was originally the
> intention for the product, but the approach had problems, so they moved
> to an alternative method of erasure.
>
> > Wikipedia....EPROM...citation 6...is a May 10 1971 article from
> > Electonics Magazine by Dov Frohman, who apparently "invented the EPROM".
> > Google.....
> >
> >  http://www.jmargolin.com/patents/eprom.htm
> >
> > references the article, and interviews the author later in 1993. The
> > text say Intel shipped that 1702 EPROM "with a window because X-rays
> > ....disrupted the structure" of the chip. The Web page has some details.
> > I"ve not (yet) read the article, or checked the patent.
> >
> > This suggests that X-rays were not a production nor a customer practice.
>
>   Yup.  But we already knew that. ;)
>
> > so: Can you cite a reference I can find also, that shows a product
> > announcement, or a production data sheet, that says specifically that a
> > customer can erase a specific PROM product using X-rays of a particular
> > wavelength and energy for a particular period of time?
>
>   No.  I never said there were commercial products or production parts
> that were intended to be erased with X-rays.
>
>   I get the strong impression that you think I asserted that there were
> production EPROMs which were intended to be erased in the field using
> X-rays.  I made no such assertion.
>
> > I'll grant the possibility this occurred for some very early product,
> > some early development in the semiconductor lab, or some military or
> > other specialized application.
>
>   I think we can assume it had been done in the development lab because
> the developer states that it "caused" a problem.  Not "could cause",
> "may cause", but "caused".
>
> > I'll grant some hackers could borrow a
> > dental X-ray and erase an EPROM - did they do subsequent life-tests?
> > Even that description would be of interest. Thank you.
>
>   I have no idea if anyone has tried it outside of the original
> development lab.  But I have an X-ray system, I could certainly try it
> in my lab, or facilitate such experimentation here for others who have
> more free time than I do.
>
>                 -Dave
>
> --
> Dave McGuire, AK4HZ
> New Kensington, PA
>