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Digital photography All-in-one desk reference 3rd edition - Busch D.

Busch D. Digital photography All-in-one desk reference 3rd edition - Wiley publishing, 2006. - 755 p.
ISBN: 0-470-03743-1
Download (direct link): digitalphotographyallinone2006.pdf
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Book II Chapter 2
Setting Up a Computer for Digital Photography
122 Archiving and Backing Up
even mammoth 500GB hard drives could be purchased for a lot less than 50 cents per gigabyte, and I expect the cost per byte will drop even more dramatically during the life of this book as the latest 750GB and larger disks become standard. However, even at 50 cents per gigabyte, hard drives arenít that much more expensive than CD-R media.
External hard drives
With external hard drives, youíre no longer limited to the number of disk drives you can cram into your computerís housing. These disks link to your computer using an IEEE 1394 (FireWire) or USB 2.0 interface, such as the one shown in Figure 2-2.
Figure 2-2: This drive uses slide-out trays to allow hot-swapping one disk drive for another.
The advantage of external storage is that you can install and remove FireWire and USB 2.0 drives without opening your computerís tower, and you donít need to worry about how to fit them in the case. You can also easily move such an external drive from computer to computer.
Archiving and Backing Up
Digital photos can fill even the largest hard drive faster than Yankee Stadium on Bat Day. Your graphics powerhouse needs open-ended storage
Avoiding Microprocessor No-brainers 123
that is relatively cheap and reliable and that provides near-online (permanent storage) access speeds.
Zip disks (R.I.P.)
I mention Zip disks because they eventually became a part of popular culture, almost turned into a generic term, and threatened to replace the floppy disk before $40 CD and DVD burners killed them off. Today, you see Zip disks only in old spy movies in which a secret agent copies crucial data while a bar graph on the computer display shows the progress. Today, solid state ďthumbĒ or ďjumpĒ drives do the same thing more cheaply and plug right into your USB port. (The latest spy movies show the agents using a thumb drive, but the bar graph remains maddeningly slow because the need for suspense hasnít been eliminated by the pace of technology.)
CD-Rs and CD-RWs
CD-R and CD-RW discs have a bit more credibility in this arena because you can cram a healthy 700MB on a CD that can cost as little as a nickel. You still wouldnít want to back up your 160GB drive to 200 CD-RW discs (even though the media itself might cost you only $20), but itís entirely practical to archive your digital photos on this media if you are using a camera with no more than 5 or 6 megapixels of resolution. For cameras that produce larger files, even CDs donít have much capacity.
DVDs have become a more viable long-term storage medium, even though the basic one-layer DVD barely holds the contents of a 4GB memory card. (And those of us with higher-resolution cameras can fill up a 4GB card very quickly; on a recent trip I snapped roughly 4GB of photos every day for ten days running.) Depending on how many layers are used, DVDs can store up to 8GB or more each. The cost of DVD burners is coming down, and this medium should become more popular when the industry settles on a single, standard format. In a world with DvD-ROM, DVD-RAM, DVD+RW, and DVD-RW, the best plan is to buy a DVD burner that supports them all. Things might become more complicated in the future when the newer, extra-high capacity DVDs (including the blue-laser Blu-ray discs) become available.
Avoiding Microprocessor No-brainers
The fastest microprocessor might not be absolutely essential for image editing if youíre using a digital camera with about 5 megapixels of resolution. Higher resolutions call for more horsepower, however, and if youíre buying a new machine, thereís no reason not to buy one with the fastest microprocessor available, within reason. The microprocessor is what processes many of
Book II Chapter 2
Setting Up a Computer for Digital Photography
124 Determining Whatís Most Important
your program instructions ó everything that isnít handled by a separate digital signal processing chip. So the faster the microprocessor runs, the faster your image editing software will work, generally speaking.
Each individual element of an image involves from 1 to 4 or more bytes of information. An RGB (red/green/blue) image requires 3 bytes per pixel, a CMYK (cyan/magenta/yellow/black) image needs 4, and additional alpha (selection) channels take up 1 byte each. Even a relatively minuscule 640 x 480, 24-bit image can involve nearly 1MB of data.
If you ask your image editor to apply an image-processing filter to an entire image, your microprocessor must calculate the effects of that filter on each and every one of those million bytes. That can take a second or two with a very fast system or as long as a minute or much more with very slow computers.
And although there are other constraints (such as memory or hard drive speed), the speed of the microprocessor affects nearly everything you do on your system. As you might guess, a fast CPU should be a major consideration when assembling a graphics workstation from scratch. You might not need the fastest microprocessor available, but then again, you never hear anyone complaining that a computer is just too darn fast.
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