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How many books can you store in 1 GB hard drive?

December 6, 2010 34 comments

As explained in my previous post Few rules of thumb

Let’s apply Rule #7 to this problem. As the rule says, “A character is represented by 8 bits” i.e. each character takes about 8 bits. Please note that this problem can be solved only by making few assumptions and your solution depends on the kind of assumptions you make.

Let’s solve the problem now:

  • we know 1 byte = 8 bits (Ref. table at the end of this post)
    • 1 GB (giga byte) = 1073741824 bytes (≈ 109 bytes) [read it as, 10 power 9]
    • 1 GB = 8 * 109 bits
  • Now assume on an average every word is comprised of 5 characters
  • Assume every page has about 10 lines and each line has about 20 words => 200 words per page
  • Number of characters in each page => 5*200 = 1000 characters per page
  • Assume every book has about 300 pages => 1000*300 = 300000 characters per book
  • Now that every book has about 300,000 characters. The amount of memory taken by each book is
    • 300,000 * 8 = 2400000 bits (≈24*105 bits of space)
    • The above principle states that each book takes about 24*105 bits of space
  • Now, how many bookscan be stored in 1 GB hard drive?
    • (8 * 109 )/ (24*105) ≈ 3333.33 books (It’s corrected now. Thanks to the comments)

Answer to the question is… In 1 GB hard drive you can store about 3334 books with the kind of assumptions we made!

We used following conversions to solve the above problem:

  • 1 Byte = 8 Bit
  • 1 Kilobyte = 1024 Bytes
  • 1 Megabyte = 1048576 Bytes
  • 1 Gigabyte = 1073741824 Bytes