Episode 11

[Intro Music]

[Keith] Welcome to A Couple Of Admins Podcasting. I'm Keith Albright

[Rich] and I'm Rich Niemeier.

[Ted] and I'm Ted Miller

[Otto] and I'm Otto Kopeczky

[Keith] This is Episode 11, a special topics episode recorded on August 7th, 2007. Today we will be discussing 'Preserving Digital Data'.

I'd like to introduce a new participant to the show. Please welcome Otto Kopeczky (Kopetzky). Otto is a friend of Ted's and has agreed to jump in and have some fun with us.

Preserving Digital Data - Protecting your digital information for the long run

• Media Deterioration

• Technical Obsolescence of media (Rich's angle)

Rich's Notes

• Hard Disk MTBF: Flap or Farce?

By David Morgenstern February 28, 2007 in eweek "....Some drives are rated at 1.5 million hours.

Now, that's a good stretch to time. After all, a year is only 8,760 hours. One million hours comes to a bit more than 114 years. Some may be scratching their heads, since the hard drive itself has only been around for 50 years (IBM's giant 350 Disk Storage Unit for its RAMAC computer). This can be confusing."

link:http://www.eweek.com/article2/0,1895,2099467,00.asp

• Disk failures in the real world:

What does an MTTF of 1,000,000 hours mean to you? Bianca Schroeder Garth A. Gibson Computer Science Department Carnegie Mellon University {bianca, garth}@cs.cmu.edu

• basically this article sheds light on the fact that Hard drives do not deteriate at a constant rate.

link:http://db.usenix.org/events/fast07/tech/schroeder/schroeder_html/index.html

• OSTA and Ecma Join Forces to Establish Industry-wide Optical Disc Archival Testing Standard *

"The anticipated end result is increased user awareness of archival quality of optical media as a critical purchase parameter," explained Smith. "This will enhance customers' ability to make informed purchases appropriate to their application needs by providing a standardized evaluation result indicator. This product differentiation is intended to eliminate any guesswork that takes place when deciding which media to use when long life of data is a desirable attribute."

 SOURCE Optical Storage Technology Association

How to handle cd's Link:http://www.osta.org/technology/cdqa12.htm

• USB Flash Drives - You CAN Take

It with You

• subsection:Flash Memory Demystified

BY..imatation corp Flash memory has a write endurance limit. This limit is the number of times the flash memory cell can be written until it can not be restored to its initial condition. The industry refers to this as the erase cycles. The endurance is rated between 10,000 and 100,000 erase cycles for different types flash memories. link:[[http://www.imation.com/didyouknow/technology_info/USB_Flash_Drives_Take_it_with.html}}

Keith's Notes

Do home-burned CDs? have only a brief lifespan? Commercially-produced CDs? (like the ones you buy in record stores -- pressed not burned) are supposed to last much longer. We use CDs? for digital archiving (music we've played, pictures we've taken, things we've written, etc.) and it's dismaying to think these things could soon perish.

Commercial CD burners burn pits into an aluminum substrate with a high energy laser. Home CD-Rs use a much lower powered laser to "burn" photo-reactive dye. Photo-reactive dye is photo-reactive. Sunlight contains a full spectrum (pretty much all) wavelengths of light. Leave a CD-R out in sunlight and it is likely to go bad. Commercial CDs? don't have this problem but the apparatus to make them isn't cheap.

Page 12: "How Long Can You Store CDs? and DVDs? and Use Them Again?" Among the manufacturers that have done testing, there is consensus that, under recommended storage conditions, CD-R, DVD-R, and DVD+R discs should have a life expectancy of 100 to 200 years or more; CD-RW, DVD-RW, DVD+RW and DVD-RAM discs should have a life expectancy of 25 years or more. Little information is available for CD-ROM and DVD-ROM discs (including audio and video). Expectations vary from 20 to 100 years for these discs.

Of course, you must follow the suggested handling procedures '''Quite a bit of research has been done on care and retention of CDs?. The most important factors are:

The quality of the lacquer on top of the data substrate The quality of the burn How you label them Where you keep them.''' Imation makes CD-Rs that have a lifetime guarantee.

If you burn a CD at 1x, each hole has more definition than if you burn it at 12x. This is because even a tiny electronic laser takes some time to turn on and off. The size of the dot and the spin rate combine to make this time cover a sizeable percentage of the hole. The longer you want to keep a CD, the longer you should take to burn it. Cheaply-burned CDs? are said to last 12 to 24 months.

The closest surface to the data layer on a CD is the top. The gum in a paper label is going to speed up the break-down of the protective lacquer there. Use a sharpie, and nothing more.

Keep the really important ones in a cool dry place, without weight on them.

Keep Two Copies

A CD-R disc might last for decades, but if you drop the disc on the floor and roll over it with your chair, the lifetime will be dramatically reduced. If you plan to keep important data for long-term storage, keep a "working copy" and an "archive copy". Use the working copy when you need to browse your old data, and leave the archive copy untouched until you absolutely need it. If the working copy is damaged or destroyed, you can use the archive copy to create a new working copy.

Don't Screw Up the Dye Layer

Most folks take great care to protect the bottom of their CD-R discs, because the laser reads data from that side. However, the most sensitive part of the CD-R disc is actually the top, which contains the dye layer. The durability of the dye layer varies, but one thing is certain: if you scratch it or tear it off, your data is gone for good. Use only felt tip permanent markers to write on the top of the CD-R disc, and never apply adhesive labels to a long-term archive copy. Adhesives degrade rapidly, and when the label starts to peel or tear off, it could take the dye layer with it.

Also, keep your CD-R discs in sealed containers away from bright lights, heat and water. CD writers use laser light to write the data on the dye layer, but sunlight, bright room lights and heat cause the dyes to degrade quickly. Water will not harm the plastic disc, but exposure to liquid water may damage the dye layer.

Use Industry-Standard Data Formats

Suppose you want to archive some family photos. You might scan them into your favorite photo editing software and save them on CD-R, thinking they will be preserved for decades. But what if your favorite photo editing software is long gone? In fact, by the time you are ready to use the photos again, computers and operating systems may have changed dramatically.

You can minimize the risks by doing your research carefully and choosing data formats which are likely to stand the test of time. Here are some good examples of long-term storage formats. I won't go into detail about these choices, but these are good starting points for your own research.

• Given the flash memory lifetime write issues, what about flash-based devices like iPods and other MP3? players?
• Dormant disk idea - MAID=Massive Array Of Idle Disks write it and shut it off. Barring physical damage, it can be fired up later and retrieved. Concept of WORO - Write Once, Read Occasionally

Link: http://www.nla.gov.au/niac/meetings/npo95rh.html
Link: http://forum.doom9.org/archive/index.php/t-98273.html
Link: http://www.itl.nist.gov/iad/894.05/gipwog/surveyresults2005.ppt#484,3,GIPWoG
Link: http://www.plasmon.com/downloads/pdf/opticalmedialifeprediction.pdf
Link: http://www.willamette.edu/wits/idc/mmcamp/LongTermDataStorageOnCD.htm
Link: http://www.ifs.tuwien.ac.at/~aola/publications/thesis-ando/Longevity_archival.html
Link: http://www.keller.com/dan/CDs.html
Link: http://ask-leo.com/can_a_usb_thumbdrive_wear_out.html
Link: http://ask.metafilter.com/63310/Thumb-Drive-Life-Cycle
Link: http://en.wikipedia.org/wiki/Massive_array_of_idle_disks

Ted's Notes Online data storage seems like a safe option until you read their "Terms of service." I looked at three sites that provide this service and I found similar language in their policies.

• THE SERVICE IS PROVIDED TO YOU ON AN "AS IS" AND "AS AVAILABLE" BASIS.

• "My Docs Online, Inc. ("MYDOCS") makes no guarantees as to the continuous availability of the Service or of any specific feature(s) of the Service. MYDOCS reserves the right to change the Service or the terms and conditions of this Agreement at any time without notice."

• "Berkeley Data Systems reserves the right at any time to modify, suspend, or discontinue providing the Service or any part thereof in its sole discretion with or without notice. Berkeley Data Systems will use commercially reasonable efforts to notify you of modification, suspension, or discontinuance of the Service either by sending an email to the email address you provide with your registration or by a posting on Mozy.com website. However, in no event will Berkeley Data Systems be liable to you or to any third party for any modification, suspension or discontinuance of the Service with or without notice."

Last Call

Last chance to state your views or opinions on the matter......

Closing

All right, well that is it for the show. For listener feedback; you can email us at RichandKeith? [at] gmail.com or you can post a comment on the main site at ACoupleOfAdmins.com or, if you use iTunes, write a review. Lastly, you can drop any show ideas or topic requests on the wiki. There is a link to the wiki on the main show site. If you would like to participate in the show; either through an interview, a segment contribution, or any other way, please let us know.

Thanks everyone.