One of the main reasons our software is often so difficult to use is because its designers have made rational, logical assumptions that,
However, when we apply memory via task
In the physical world, storing and retrieving are inextricably linked;
A
storage system
is a method for safekeeping goods in a repository. It is a physical system
As we discussed in Chapter 13, disks and files are usually rendered in implementation terms rather than in accord with the
We can own a book or a
It is important that there be a proper place for our books and hammers, because that is how we find them when we need them. We can't just
In this model, which works just fine in your home, the storage system is the same as the retrieval system: Both are based on remembering locations. They are
This system of everything in its proper place sounds pretty good, but it has a flaw: It is limited in scale by human memory. Although it works for the books, hammers, and spoons in your house, it doesn't work at all for the
In the world of books and paper on library
The solution was an
index
, a collection of records that allows you to find the
location
of an item by looking up an
attribute
of the item, such as its name. Traditional library card catalogs provided lookup by three attributes: author, subject, and title. When the book is entered into the library system and assigned a number, three index cards are created for the book, including all particulars and the Dewey Decimal number. Each card is headed by the author's name, the subject, or the title. These cards are then placed in their respective indices in alphabetical order. When you want to find a book, you look it up in one of the indices and find its number. You then find the row of shelves that contains books with numbers in the same range as your target by examining signs. You search those particular shelves, narrowing your view by the lexical order of the
You
physically
retrieve the book by participating in the system of storage, but you
logically
find the book you want by participating in a system of retrieval. The shelves and numbers are the storage system. The card indices are the retrieval system. You identify the desired book with one and fetch it with the other. In a typical university or professional library, customers are not allowed into the stacks. As a customer, you identify the book you want by using only the retrieval system. The librarian then fetches the book for you by participating only in the storage system. The unique serial number is the bridge between these two interdependent systems. In the physical world, both the retrieval system and the storage system may be very labor