Sunday, March 20, 2011

How Reliable Are Digital Files ?

Are Stone Carvings & Written Word
More Lasting Than Digital Files?
Quite Likely.......

The long term reliability of digital files is far from being 'written in stone', so to speak. For example, have you ever downloaded or received a file which your computer could not open, simply because of the format the data is stored in? Are Mac files and PC files compatible? Ever try to read a floppy disk on your brand new netbook? Floppy drive?? What's that??

Just what is the reliable lifespan of a CD Rom, a hard disk drive or those cute little memory sticks? How well, does any of these storage methods stand up to climate extremes? Do they tolerate freezing and thawing in a moist environment? If you leave them on the dash of your car on a hot summers day, will they simply melt? What happens to those 3200 books on your kindle, if you drop it on a hard surface? Get it wet?

In the last 30 years or so when IBM introduced the 5100 with an astounding 16K of memory for just less than $9,000 the technology has exploded so that today for less than $500 you can buy a dual processor PC with 1 Terabyte of memory. During that time storage on a single floppy disk was an incredible 1.3 MB and has grown to single memory flash drives capable of storing 64 GB for less than a $100. With every advance in the technology the ability to access old data files becomes more and more of a challenge, and that does not address the longevity of the media itself.
Two Problems With Maintaining Digital Files

As already outlined the format that data has been saved in as well as the physical means of storage are two issues challenging the lifespan of digital files. As pointed out by the British Joint Information Systems Committee: "Preservation is therefore a more immediate issue for digital than for traditional resources. Digital resources will not survive or remain accessible by accident: pro-active preservation is needed".

You can leave a book on a shelf for ages and barring a fire or other calamity, when you open it up the words will still be there for all to see and read. That is not as certain with digital storage mediums, they tend to work or not work, and they don't give any warning of the fact they failed, while just sitting there. If the actual storage medium is still functional, you will also have to be able to actually read the files in the format they were saved. Ever try to open a MS Office 2010 document with a version of MS Office 98?

The US Commission on Preservation and Access (Task Force 1996) outlined needed technical approached to maintaining digital information. The Commission recommends refreshing, migration and emulation in the maintenance of digital files.

Refreshing involves moving a file from one storage medium to another avoiding the physical decay or the obsolescence of that medium. Because physical storage devices (even CD-Roms) degrade, and technological changes render older storage devices (such as floppy drives) unusable to newer, ever changing computers, some continuing form of refreshing will be necessary for many years to come. 

Migration is an approach involving periodically moving files from one encoding format to another that is readable in a more modern computing environment. (An example would be moving a Wordstar file to WordPerfect, then to Word 3.0, then to Word 5.0, then to Word 97.) In a photographic environment older Photoshop files are no longer readable and need to be updated into a new format. Migration seeks to limit the problem of files encoded in a wide variety of file formats that have existed over time by gradually bringing all former formats into a limited number of contemporary formats.

seeks to solve a similar problem that migration deals with, it's approach focuses on the applications software instead of  the files containing information. Emulation backers want to build software that copies every type of application that has ever been written for every type of file format, and make them run on whatever the current computing environment is. (So, with the proper emulators, applications like Wordstar and Word 3.0 could effectively run on today's machines.) 

The actual decay of digital storage devices is another issue needing to be considered and as pointed out already, digital media has the tendency to either be fully functional or fail completely and unless you open the file, you have no way of knowing. The only way to safeguard data (for example your wedding pictures or kid's birthdays) would be to keep the data on several different means of storage. For example the same data could be on your hard drive on your PC, on a CD-Rom and on a memory stick. All of which you should check periodically to make sure they are still intact and nothing has become corrupt.

So while, technology has made gargantuan strides in the last few decades it is arguable that digital storage of important knowledge you wish to pass on to future generations, is perhaps not as capable of standing the ravages of times as the good old stone tablet, and written scroll.

One last challenge to the digital method of storing data ..... if you pull the plug, the whole thing is useless. On the other hand with a good old fashioned printed book, even if the power goes out, you can always light a candle or move your desk to the window, and I don't mean the MS kind.


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