Part 2: Software (Chapter 5 through 9)
As you shift your attention from hardware to software, it's appropriate to think of hardware as the vehicle and software as the driver. Or, if you prefer the concept of layers of activity, hardware is the bottom layer, and software sits on top. In fact, though, we'll see that software itself comprises a number of layers. The first of these is the operating system (OS), the layer in software that is responsible for managing the hardware-software partnership. The principles of the OS are covered in:
Over the years, systems developers have created multiple kinds and types of operating systems. Some of these variations are principally the consequence of improvements in technology, while others are largely the result of market forces. Whatever the reason or reasons, diversity in operating systems is a fact that must be dealt with by those planning to rely on computers in today's economy. Indeed, although Microsoft dominates the desktop, the choice for a system used for a complex activity like e-commerce includes quite a few viable alternatives and is not so easily made. We consider OS options in:
Continuing with the e-commerce example, the choice of OS is not the last software decision. The core of your business will be some sort of database. This is the software that will track your inventory and sales, and lots of other essential functions. One way of creating this software is to "roll your own"—hire some programmers and custom build everything you need. The process of software development, including programming languages and the hot area of "objects" is covered in:
Of course, you don't need to write your own software from the ground up—you can buy off-the-shelf packages that are already fully functioning databases, spreadsheets, or whatever. There are a lot of choices here, and the last chapter in this section puts considerable emphasis on how databases function and the different types now on the market. The concluding part of this chapter discusses the increasingly important issue of software reliability.