How do you store your memory cards?
Mar 16, 2021 02:06:29 #
drrobins
Loc: San Francisco East Bay (Walnut Creek)
Longshadow wrote:
Compared to CCDs, 20 years is a long time.
I started out in R&D at Sperry Univac for disk and tape heads in 1972.
Don't recall anyone ever referring to the magnetism on a disk or tape "bleeding off"; "dissolving"; "going away" over time.
Maybe it's been long enough now that they have info???
Love to see your source.
I started out in R&D at Sperry Univac for disk and tape heads in 1972.
Don't recall anyone ever referring to the magnetism on a disk or tape "bleeding off"; "dissolving"; "going away" over time.
Maybe it's been long enough now that they have info???
Love to see your source.
Mar 16, 2021 02:18:15 #
drrobins
Loc: San Francisco East Bay (Walnut Creek)
Longshadow wrote:
Compared to CCDs, 20 years is a long time.
I started out in R&D at Sperry Univac for disk and tape heads in 1972.
Don't recall anyone ever referring to the magnetism on a disk or tape "bleeding off"; "dissolving"; "going away" over time.
Maybe it's been long enough now that they have info???
Love to see your source.
I started out in R&D at Sperry Univac for disk and tape heads in 1972.
Don't recall anyone ever referring to the magnetism on a disk or tape "bleeding off"; "dissolving"; "going away" over time.
Maybe it's been long enough now that they have info???
Love to see your source.
Sorry. I don’t have a peer-reviewed paper on magnetic field deterioration over time. But there are many articles about this on the net, some from hard drive manufacturers. Some of the articles refer to loss of magnetism in permanent magnets. While that’s not the data disk, it’s the same in all magnetized media. Slow for sure, but field strength eventually fades to where data reading is unreliable. Can be fixed by rewriting the data again so the magnetism starts out full-strength again. One article says a 50% loss of strength by 69 years, but other articles say reliability falls by between 9-20 years.
More likely unable to read a drive in long term storage due to mechanical or electrical failure. Bearings freeze up, motors can’t start. That part is said to be as short as 5 years.
Mar 16, 2021 08:06:14 #
drrobins wrote:
...
...
... One article says a 50% loss of strength by 69 years, but other articles say reliability falls by between 9-20 years.
More likely unable to read a drive in long term storage due to mechanical or electrical failure. Bearings freeze up, motors can’t start. That part is said to be as short as 5 years.
...
... One article says a 50% loss of strength by 69 years, but other articles say reliability falls by between 9-20 years.
More likely unable to read a drive in long term storage due to mechanical or electrical failure. Bearings freeze up, motors can’t start. That part is said to be as short as 5 years.
Okay, minimum of 10 years? Maximum of a person's lifetime?
Suffice to say longer than needed as the drive may fail for other reasons before the data itself goes bad.
And of course it depends on the read recovery circuitry design. I analyzed that also.
I'm not worried about any magnetic degradation in the data itself as chances are the drive will fail way before that happens, separate scenario.
Apr 7, 2021 14:22:40 #
I use smaller containers to carry cards and preserve them from excessive water (waterproof) in the event of rain, and dust. Each container holds 8 cards. The cards fit in a card shaped form and they stay in the order you put them in. If I'm on a trip, I prelabel them "day 1, 2" etc. Then I know where I am and what to expect on each card. If I'm on a long trip, I might have three or four containers. Lightweight, small enough to put in a pocket or purse and secure. Needless to say, I never have filled any media card, but that's ok. I shoot what I want, when I want. That makes me happy.
If you want to reply, then register here. Registration is free and your account is created instantly, so you can post right away.