Linked by Thom Holwerda on Wed 11th Jun 2014 14:03 UTC
Mac OS X

HFS+ lost a total of 28 files over the course of 6 years.

Most of the corrupted files are completely unreadable. The JPEGs typically decode partially, up to the point of failure. So if you're lucky, you may get most of the image except the bottom part. The raw .CR2 files usually turn out to be totally unreadable: either completely black or having a large color overlay on significant portions of the photo. Most of these shots are not so important, but a handful of them are. One of the CR2 files in particular, is a very good picture of my son when he was a baby. I printed and framed that photo, so I am glad that I did not lose the original.

If you're keeping all your files and backups on HFS+ volumes, you're doing it wrong.

HFS+ is a weird vestigial pre-OS X leftover that, for some reason, Apple just does not replace. Apple tends to be relentless when it comes to moving on from past code, but HFS+ just refuses to die. As John Siracusa, long-time critic of HFS+, stated way back in 2011:

I would have certainly welcomed ZFS with open arms, but I was equally confident that Apple could create its own file system suited to its particular needs. That confidence remains, but the ZFS distraction may have added years to the timetable.

Three years later, and still nothing, and with Yosemite also shipping with HFS+, it'll take another 1-2 years before we possibly see a new, modern, non-crappy filesystem for OS X. Decades from now, books will be written about this saga.

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M.Onty
Member since:
2009-10-23

Readable life span of hard discs assumed to be ~5-15 years.
"""" burned CDs known to be ~10 years
"""" pressed CDs assumed to be 20--100 years
"""" magnetic tape known to be ~30 years
"""" standard print paper known to be as low as ~50 years
"""" 35mm film known to be ~80 years
"""" burned 'gold' CDs assumed to be ~300 years
"""" vinyl assumed to be 500+ years
"""" 'archive' cotton paper known to be 500+ years
"""" vellum known to be 1000+ years
"""" bloody great slabs of stone engraved in big letters known to be 10,000+ years

All this is before considerations about whether data is stored in analogue or digital, and what technology is required to read it back.

Reply Parent Score: 4

Alfman Member since:
2011-01-28

M.Onty,

All this is before considerations about whether data is stored in analogue or digital, and what technology is required to read it back.


It's an interesting list, good food for thought!

With analog representations, like film or audio tape, there's no "moment" that the data went bad, it's just a slow process. There's no way to recover lost fidelity. This is an advantage of digital representations, which can be reproduced indefinitely with no loss of data by taking care to verify each copy is accurate. With this in mind, it's unlikely that humanity will ever loose the digital works created today so long as society possess the will and technical ability to create exact duplicates.


bloody great slabs of stone engraved in big letters known to be 10,000+ years


It depends if it's exposed to weather or not. Visiting a cemetery with gravestones shows that they really don't fare so well:
http://www.freephotos.se/view_photo.php?photo=889&cat=0&order=date

Marble is probably a better choice.

I suspect pressed disks (aka DVDs) would last a great deal longer if they were less information dense. The more material there is to represent a state, the more difficult it is to change/misread that state.

Reply Parent Score: 4

M.Onty Member since:
2009-10-23

With some mediums the decay is indeed very gradual. Film most notably. I was using the point at which it becomes impossible to recover the most important data as shorthand for 'life span'. So in film's case after 80 years you would probably just about be able to recover the original colour values, albeit without that much confidence in their accuracy.

With some others like magnetic tape it seems to be more clearly defined.

Also, I must point out that marble is a kind of stone. Pick the right type, carve your letters large enough and you can get 10,000+ years. (Even if they have to be so large they basically just say "I was here".)

But regardless of the technicalities, I was emphasising that all this life span business is really no more complex than picking the most robust material you can, writing the data as big as you can, in an actual language (which is neither analogue nor digital).

A better way is to make something interesting enough that you known people will be continually maintaining it and copying it. See English hill figures.

Reply Parent Score: 3

someone Member since:
2006-01-12

But you do get "bit rot" in stone slabs and vellum (another good reason to store as much data as possible in plain text formats, which is not possible in the case of photos)

Edited 2014-06-12 01:47 UTC

Reply Parent Score: 1

Alfman Member since:
2011-01-28

someone,

But you do get "bit rot" in stone slabs and vellum (another good reason to store as much data as possible in plain text formats, which is not possible in the case of photos)



In rome, I was amazed to see how the monuments appeared to have "melted" due to the effects of rain over roughly two thousand years:
https://en.wikipedia.org/wiki/Colosseum#mediaviewer/File:Rome_%2...

Also the Roman Forum is littered with stone monuments that have cracked apart and fallen to the ground. The remaining pieces are amazing, yet it's clear that only fragments of the original structures managed to survive:
https://en.wikipedia.org/wiki/Roman_Forum#mediaviewer/File:Roman_for...

Many stone monuments undergo preservation efforts to ensure they don't break apart further, even relatively new stone structures are already cracking:
http://www.nytimes.com/1989/11/24/us/a-face-lift-for-mount-rushmore...


So, while some stone remnants might last thousands of years, most will not survive, at least not without some kind of sheltered environment. For what it's worth, the scientists at NASA decided to use golden disks containing both audio and data to leave a mark of humanity in outer space for the ages:
https://en.wikipedia.org/wiki/Voyager_Golden_Record

The KEO project, a time capsule of humanity is also relevant here, uses specially made DVDs:
https://en.wikipedia.org/wiki/KEO

This is more interesting than HFS+, right? ;)

Edited 2014-06-12 03:56 UTC

Reply Parent Score: 4

zima Member since:
2005-07-06

another good reason to store as much data as possible in plain text formats, which is not possible in the case of photos)

But there are text-based image formats! ;)

Install IrfanView and open any photo with it. Now choose "Save as..." and pick PBM/PGM/PPM and in the options of saving those formats choose "Ascii encoding"

Now open the resulting file in a text editor. ;)

Reply Parent Score: 2

ezraz Member since:
2012-06-20

Readable life span of hard discs assumed to be ~5-15 years.
"""" burned CDs known to be ~10 years
"""" pressed CDs assumed to be 20--100 years
"""" magnetic tape known to be ~30 years
"""" standard print paper known to be as low as ~50 years
"""" 35mm film known to be ~80 years
"""" burned 'gold' CDs assumed to be ~300 years
"""" vinyl assumed to be 500+ years
"""" 'archive' cotton paper known to be 500+ years
"""" vellum known to be 1000+ years
"""" bloody great slabs of stone engraved in big letters known to be 10,000+ years

All this is before considerations about whether data is stored in analogue or digital, and what technology is required to read it back.


great list! i have my most important music on vinyl, one of the finest uses of PVC plastic ever.

i'd like to add some small observations --

magnetic tape lasts longer than 30 years, because i have cassettes that old that still play. many 8 tracks from the 70's still work. cassette was a cheap and fragile tape. tv stations i worked at kept their entire archives on expensive 2" tape, and expected it to last 30+ years. they stored it properly, away from moisture, heat, sunlight, and temperature changes.

i had a buddy about 10 years ago that really got into cd brands and types of coating, etc, so that he could archive all of his production work and his software in the safest way he could afford. after researching he bought pretty expensive cd-r's and burned them slowly, filling a whole cd-book with his content.

not 6 months later he's bragging about how smart he was to do this and i say i want to see these amazing cd-r's. he pulls out his book and is flipping the pages all proud of himself and a few pages in i see what looks like a crack going down one of the discs. he flipped past it so i asked him to go back, i want to see what that was, and sure enough it was a full crack in the foil layer inside of the plastic. he set the book down mad, so i flipped through and about every 1/5 discs was disintegrating inside the plastic with some sort of foil that was turning into a dried crispy flake. completely unreadable after 6 months.

luckily he hadn't wiped all his external drives yet so i don't think he lost any data, but since then i've never trusted optical for anything critical.

Reply Parent Score: 1