A Lesson Learned

You know how backups work great until you really need them? Below the fold, a lesson learned from my recent example of this phenomenon.

Optical Media Durability Update

Three years ago I posted Optical Media Durability and discovered:

Surprisingly, I'm getting good data from CD-Rs more than 14 years old, and from DVD-Rs nearly 12 years old. Your mileage may vary.

Two years ago I repeated the mind-numbing process of feeding 45 disks through the reader and verifying their checksums. A year ago I did it again.

It is time again for this annual chore, and yet again this year I failed to find any errors. Below the fold, the details.

What Is The Point?

During a discussion of NFTs, Larry Masinter pointed me to his 2012 proposal The 'tdb' and 'duri' URI schemes, based on dated URIs. The proposal's abstract reads:

This document defines two URI schemes.  The first, 'duri' (standing
for "dated URI"), identifies a resource as of a particular time.
This allows explicit reference to the "time of retrieval", similar to
the way in which bibliographic references containing URIs are often
written.

The second scheme, 'tdb' ( standing for "Thing Described By"),
provides a way of minting URIs for anything that can be described, by
the means of identifying a description as of a particular time.
These schemes were posited as "thought experiments", and therefore
this document is designated as Experimental.

As far as I can tell, this proposal went nowhere, but it raises a question that is also raised by NFTs. What is the point of a link that is unlikely to continue to resolve to the expected content? Below the fold I explore this question.

Optical Media Durability: Update

Two years ago I posted Optical Media Durability and discovered:

Surprisingly, I'm getting good data from CD-Rs more than 14 years old, and from DVD-Rs nearly 12 years old. Your mileage may vary.

A year ago I repeated the mind-numbing process of feeding 45 disks through the reader and verifying their checksums. It is time again for this annual chore, and once again this year I failed to find any errors. Below the fold, the details.

Optical Media Durability: Update

A year ago I posted Optical Media Durability and discovered:

Surprisingly, I'm getting good data from CD-Rs more than 14 years old, and from DVD-Rs nearly 12 years old. Your mileage may vary.

It is time to repeat the mind-numbing process of feeding 45 disks through the reader and verifying their checksums. Below the fold, this year's results.

Optical media durability

At last I started clearing out the garage laundry room cupboards, which is where amongst much other stuff the optical media backups I take every week have been accumulating for many years. They have been stored in a fairly warm shirt-sleeve environment with no special precautions. So to get some idea of the durability of writable optical media, I've been somewhat randomly pulling groups of backups out of the stacks and re-verifying the MD5 checksums, which were all verified immediately after writing.

TL;DR: Surprisingly, I'm getting good data from CD-Rs more than 14 years old, and from DVD-Rs nearly 12 years old. Your mileage may vary. Below the fold, my results.

Evanescent Web Archives

Below the fold, discussion of two articles from last week about archived Web content that vanished.

Abby Smith Rumsey's "When We Are No More"

Back in March I attended the launch of Abby Smith Rumsey's book When We Are No More. I finally found time to read it from cover to cover, and can recommend it. Below the fold are some notes.

Preserving personal data

4-slot Drobo

I've just started using the first product from the latest company of someone for whom I have great respect, serial entrepreneur Geoff Barrall. His previous company was Data Robotics, now Drobo after their product. I made a small investment in the company and have been using Drobos ever since the initial beta program. Geoff's team managed the all-too-rare feat in the industry of packaging up complex technology, in this case RAID, in a form that is both highly effective and very easy to use. Drobos are a wonderful way of protecting your data against disk failures - over the years the three original 4-slot Drobos in my home rack have handled disks filling up and failing with complete composure. They are now max-ed out with 2TB drives for a total of nearly 18TB of usable space; when this fills up I'll finally have to buy more units. Follow me below the fold for details on Geoff's new product.