Chapter 4: Storage

Overview

In some ways, personal computer is an inadequate name . Most people don t use a personal computer to compute. They use a computer to communicate (through e-mail or instant messaging) and to store and organize their personal data (such as e-mail, documents, pictures, and digital music). Unfortunately, while your computer presently stores this data quite well, it does a relatively poor job of allowing you to organize the information so that you can find it later.

Disk capacity has been growing at roughly 70 percent annually over the last decade . It s presently possible to buy drives with more than 250 gigabytes (GB) of storage. It s likely that 500-GB drives will become available in the next few years and that many systems will have more than one disk drive. I just did a quick check on the computer on which I m writing this chapter, and I have 283,667 files in 114,129 folders in only 200 GB of disk space. When I forget exactly where I put a file, it can take quite a while to find it again. In the worst case, I have to search the entire contents of each disk. In a few years , people will be able to store millions of files, most of which, if nothing improves , they ll never see again.

One reason people have difficulty finding information on their computer is because of the limited ability for the user to organize data. The present file system support for folders and files worked well originally because it was a familiar paradigm to most people and the number of files was relatively small. However, it doesn t easily allow you to store an image of your coworker Bob playing softball at the 2007 company picnic at a local park and later find the image when searching for documents that

• Mention Bob

• Involve sports

• Relate to company events

• Pertain to the park or its surrounding area

• Were created in 2007

The hierarchical folder structure doesn t work well when you want to categorize data in numerous ways. Therefore, we have a problem today in that we have lots of stuff to store and no good way to categorize it. In addition to categorizing information, which many people associate with attaching a fixed set of keywords to data, people need to relate data. For example, I might want to relate a picture to the company picnic, or I might want to relate a picture to Bob, who is also a member of an organization to which I donate time and effort, as a contact.

Another problem is that we store the same stuff in multiple places in multiple formats. Developers spend much time and effort creating their own, unique storage abstractions for everyday information such as People, Places, Times, and Events. For example, Microsoft Outlook has a definition of a Contact. The Microsoft Windows Address Book also has its own definition of a contact. Each instant messaging application has yet another. Each application stores its definition of a contact in a unique, isolated silo of information.

There are a number of problems with current approaches to data storage, including the following:

• Developers reinvent the basic data abstractions repeatedly.

• Multiple applications cannot easily share common data.

• The same information lives in multiple locations.

• The user repeatedly enters the same information.

• Separate copies of data become unsynchronized.

• There are no notifications of data change.