[GTALUG] War Story: Asus UX305ca SSD failures

[Russell Reiter]

On Fri, Aug 9, 2019, 1:36 PM James Knott via talk <talk at gtalug.org> wrote:

> On 2019-08-09 01:19 PM, Russell Reiter wrote:
> > Jpegs are an exported file format created from aggregated image data
> > collected by the CCD. They are digital files and subject to
> > transmission errors just like any other signal. My 13 megapixel phone
> > saves image data directly as a jpg file. Sure the raw data has been
> > manipulated before writing the original, but that is much different
> > than having an image recorded using raw format and then exporting a
> > copy in a lossy format in order to save space.
>
>
> Perhaps you need to learn about some of the technology.  Some media,
> such as CDs & DVDs use forward error correction, to ensure data is
> copied correctly.  When you transfer data over a network, there is a
> checksum used with TCP, with IP(v4) and a CRC check at the Ethernet
> level.  On top of that some applications


Umm what if two bits of the transmitted file are inverted but the count
adds up to the same checksum? Checksums report errors, it would be up to
the operator to ensure the data was copied correctly. So I can't agree with
the semantics of your statement about forward correction ensuring a correct
copy.

I think that since all these factors deal with accidental errors the term
bitrot was not correct. Bit corruption on the other hand would include
those changes induced by other corrupting factors, as opposed to
happenstance and transient errors.

provide their own integrity
> check.  So, it would be very difficult for an error to propagate.  Now


CRC as an ECC tool also has its limitations where the SNR is high.

I am aware some media will deteriorate with time, so the sensible thing
> to do is make periodic backups.


Well that is where this thread started. I think the logical conclusion of
that was, the ancient recording methods had the longest true lifespan and
as more and more technology was introduced, so did the valid life of the
data get reduced.

>
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