Thursday, November 12, 2009

Got Yottabytes?

Gleb Budman at online backup provider Backblaze has some interesting analysis on how to store the Yottabytes of data the National Security Agency will have in 2015. It will only take twice the world's GDP and fill the states of Delaware and Rhode Island with data centers. Now that's a real storage challenge.


Is Digital Archival?

Prints are still being made from Ansel Adams' negatives that are over sixty years old because they are inherently archival.

Will the same be true of digital files?

Will your children and grandchildren be able to look through a box of your digital files sixty years from now? Will the media be readable, and will there be anything to read it with?

The answer is NO if you’ve been using Sony’s AIT drives to archive and backup your files because they are being discontinued.

For over a decade, tape has been a primary archive and backup media for many IT professionals. It is considered by many to have a longer archival shelf life than hard drives. Up until the last year or two, tape was also cheaper per GB than hard drives, although that is no longer true. I suspect that the price drop in hard drive storage, coupled with new storage approaches have caused IT professionals to change their buying patterns.

In practical terms, what this means is that if you are using AIT, you need to immediately find a new backup media. It also means that it’s only a matter of time before you won’t have a drive available to read your archive of AIT Tapes. Your archive essentially just got reset to zero, because you’ll only be able to access it for as long as you can scrounge up drives on Ebay. Basically you need to rebuild your archive all over again if you’ve been using AIT tapes.

It’s becoming clear that digital files are not an archival medium, and that it takes constant investment to protect your archive in even an imperfect way. Even the Academy of Motion Picture Arts and Sciences realizes this. They’ve calculated that it’s less expensive and more archival to write digital movies to B&W separation negatives than it is to store a digital copy. In fact, they claim there is no archival digital storage method at all!!! Yikes!

All this makes the Millenniata/Cranberry archival DVDs a whole lot more interesting, but at 4.7 GB per disk, it’s not a efficient way to back up terabytes of files. And even if the media last as long as they claim, there’s still the problem of finding a reader that can read it 25+ years from now, and the cost of $16 per blank disk.

What’s my point? That we are constantly in danger of losing our digital photographs because there is no archival storage medium that we can be sure will be readable one hundred years from now. With my own eyes, I’ve seen the negative that makes Ansel Adam’s photograph Clearing Winter Storm, made in approximately 1939, and it’s still readable with the naked eye, and can be put into an enlarger and printed.

To achieve the same thing with digital we have to have media that doesn’t degrade, we need devices to read it, and we need software that still works with Windows 2070 SP6. No one has solved this one yet. Until someone does, make prints, which will be readable for a long time to come.

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Monday, November 02, 2009

What to do when the lights go out?

by Rich Seiling

This is probably the most unglamorous article that can be written about maintaining a digital imaging workstation, but believe it or not, paying attention to the electricity going into your computer is important. Computers need a constant and regular supply of electricity to maintain normal function. 

You want normal function, right?

Yes, you do, especially when you are transferring the photos from your latest amazing adventure to your hard drive.

Leave the lights on, I’m scared!

All kinds of screwy things can happen to your computer because of power outages.  Probably the worst is a hard crash, the equivalent of your computer hitting a brick wall at 50 mph with a cup of coffee in its hand.  Everything your computer was in the process of doing comes to a dead stop, and some of it goes flying all about, in a metaphorical sense. You really don’t want this to happen in the middle of a data transfer.

If you’re using a RAID to mirror your files, it makes for even more problems. A hard crash usually causes the RAID to go out of sync, which initiates a rebuild, which leaves your data without redundancy during the rebuild, and exposes you to risk of loosing your files.

What can brown-out do for you

Fortunately, there is an answer, in the form of a UPS. Not the little brown truck that delivers your online purchases, but an uninterruptible power supply. A UPS in its simplest form is a battery that continues to power your computer should there be a blackout.

The idea is to power your computer long enough to save your work and shut down it down before the battery dies. But in practice they can do even more than that. A UPS can condition power so your computer is getting a consistent voltage, and can carry you through brownouts, overvolt, or undervolt situations, all of which are probably more common they you might think. (Look at what a Main Bus B undervolt did for Apollo 13!)

Another great feature is that most UPSs can connect with your computer and turn it off before the battery runs out, so that you’re protected even when your computer is unattended.

Does this UPS make me look fat?

With a UPS, size is an important thing. If your computer and accessories draw more power than your UPS is designed for, it won’t protect you! When the power goes out, the UPS will be overloaded and it will turn off, taking your computer and devices with it!

For a UPS to be useful, you want it to be bigger than the load you intend to plug into it. To do that, you have to know how much power your computer and accessories pull. 

If you want to know the size UPS you need with great precision, buy a Kill-A-Watt watt meter that lets you measure the VA (volt amps) that your system pulls. 

Computers and other devices pull a greater load at startup than in normal operation, and your UPS has to be large enough to handle this peak load, so we need to measure it. Plug in all of your equipment, then while watching the Kill-A-Watt display, start up all of your equipment at the same time and record the peak load in VA.  (Warning! Never plug a laser printer into UPS! You’ll see this warning in the UPS instructions. The reason is that laser printers pull peak loads during use that can overload the average UPS.) Once you know your peak load, make sure that you use a UPS that is rated for at least 130% of that load.

Don’t want to do the test? OK, I’ll make it easy for you. I tested the following representative Photoshop workstation:

Mac Pro Tower

23 inch Apple Cinema Display

17 Inch CRT

It drew a peak of 345 VA at startup (or about 300VA once up and running.) This probably is close to what your workstation draws. So, in this case, you need a UPS that can handle at least  450 VA, but I’d feel much more comfortable UPS in the 750VA to 1000VA range. The price difference between the 750VA and 1000VA typically isn’t that much, so I usually go for the larger model. It also gives you room to add more accessories as your system grows.

How long will my battery last?

When you read the specs for a UPS, you’ll see an estimated runtime, which tells you how long the UPS should run without power. This measurement is usually given for a “half load”, meaning that if you are drawing half the rated load, say 500VA from a 1000VA UPS, it’s probably accurate. The larger the load, the less time the battery will last. If you are pulling anywhere close to a full load on your UPS, the battery isn’t going to last long at all, rendering it pretty much useless, so you don’t want to pull a full load!

How do you make sure you aren’t overloading your UPS? You can use the Kill-A-Watt meter, but an easier way is to choose a UPS that has a display that tells you how much load your devices are pulling. Then with a quick glance, you can tell what the load is. My personal preference is to pull no more than 50-60% of maximum power on my UPSs.

Testing your UPS

Once you have a UPS, and have everything plugged in, you need to test it. The easiest way is to use the test button (if available) but what I like to do is pull the plug of the UPS while the computer is running to see if it all still works. It may be a little dramatic, but I feel a real sense of confidence watching the computer run while I’m holding the power plug in my hand.

Where to buy

A 750-1000VA UPS isn’t the little UPS you see advertised in the Sunday circulars for $39.95. Best Buy might have them, but you may need to visit a computer store or go online to find the model you need. Expect to pay $100-$150 for a UPS this size, and watch out for shipping charges. The batteries in a UPS are made with lead, so they are heavy! You should also take care when lifting them, unless you like back pain.

Choosing bigger is usually better, but you’re not buying a UPS to run for hours at a time. If you need that kind or runtime, you need a generator and a UPS. But if you need to run multiple computers from a UPS, it’s usually cheaper to buy one big one than lots of little ones. A 1500VA battery will comfortably run two workstations, as long as they are close enough for the cords to reach the UPS.

Buying a UPS is probably the most boring $150 you’ll ever spend, but it will help you protect those thousands of dollars you’ve invested in creating priceless images. To me, it’s as vital as the $5 lens cap on my expensive lens. Not very exciting, but cheap protection for something very valuable

UPS manufacturers:




Tripp Lite

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