Storage Comparison

Vincent Bockaert,

In this article, we will compare magnetic and optical storage.

Storage Cost

Medium CD DVD 200 GB Hard disk
Type Optical Optical Hard disk - Magnetic
Cost (US$)[1] 0.25 0.75 100
Capacity (GigaByte) 0.68 4.4 186
Number of six megapixel JPEG images[2] 250 1,500 70,000
Number of six megapixel uncompressed RAW images[3] 80 500 23,000
Number of six megapixel JPEG images per US$[2] 1,000 1,500 700
Number of six megapixel uncompressed RAW images per US$[3] 320 660 230

Since US$1 allows you to store hundreds of images, deciding whether or not you want to keep an image is not worth your time. So I just back up and keep everything I shoot. Then in a later stage I then create a second series with the best images. Image management will be discussed in a future article.

Magnetic Versus Optical Storage

. Magnetic Optical
Cost Low, but higher than optical Low
Compatibility High High for CDs, lower for DVDs
Data Stability Relatively stable, but less than optical Stable, but lifetime depends on quality
Accidental Deletion of data High[4] Low as it is read-only[5]
Environmental Resistance Sensitive to shocks and power surges Sensitive to scratches
Data Recovery Excellent but can cost time and money Virtually impossible
Backup Convenience Very convenient Requires burning
Reorganizing data Easy Requires re-burning
Traveling Convenience One 200 GB disk is relatively compact 275 CDs or even 45 DVDs are bulky.

So if you make at least one magnetic and at least one optical backup, you are combining the benefits of both media.

Technical Footnotes

  1. (1) Estimation only. Prices vary a lot depending on where you buy, the quantity, the quality, the brand, and the speed rating, and in case of DVD whether it is DVD+R or DVD-R.
  2. (2) Estimated, depending on the compression and content of the image.
  3. (3) Estimated, depending on the content of the image and the camera. Compressed RAW will allow for about 60 to 70% more images.
  4. (4) Can be reduced by setting the file attributes to "Read-Only".
  5. (5) As explained earlier, risks are higher for multi-session burning.
This article is written by Vincent Bockaert,
author of The 123 of digital imaging Interactive Learning Suite
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