[ale] [OT] Lifespan of Storage Devices

[Alex Carver]

On 7/29/2012 06:29, Raj Wurttemberg wrote:
> You all will probably laugh at this. but. I am vintage computer collector
> for Commodore and Apple ][ equipment. Many if not most of my old 5.25" disks
> still work perfectly after almost 25 years. For the most part, the more
> expensive floppies appear to be the best. I can see some discoloration or
> "blotches" on my cheap floppies.

Flexible magnetic media has the longest shelf life (assuming quality 
material and proper storage environment like temperature and humidity) 
primarily because the magnetic domains are larger and less susceptible 
to reordering than any other media.  Tapes are the longest lived if 
spooled and stored correctly.  There are plenty of examples of tape 
media surviving for 40+ years if they were archived in environmentally 
controlled vaults.  There are amazingly many cases of poorly stored 
tapes still surviving to some extent (i.e. stored in a basement under 
the stairs in a cardboard box).

The main killer of tape media is print-through.  If the tape media is 
not sufficiently thick (or spooled without using a spacer layer), then 
magnetic domains on one layer of tape can imprint onto the adjacent 
layer when the tape is spooled tightly.  This takes a long time but it 
does happen eventually and will cause data corruption.  A spacer between 
the layers reduces the coupling between magnetic domains by increasing 
the distance.

Hard drive platters fall in second place.  They decay faster than tape 
because the domains are smaller and more susceptible to reordering by 
adjacent domains.  Newer technology in read/write heads (GMR) and DSPs 
for the electronics may fix that problem and put platters on par with tape.


Which reminds me, I need to fix my tape drive. :)