concept sequential programming in category .net
This is an excerpt from Manning's book Concurrency in .NET.
1.2.1 Sequential programming performs one task at a time
Sequential programming is the act of accomplishing things in steps. Let’s consider a simple example, such as getting a cup of cappuccino at the local coffee shop. You first stand in line to place your order with the lone barista. The barista is responsible for taking the order and delivering the drink; moreover, they are able to make only one drink at a time so you must wait patiently—or not—in line before you order. Making a cappuccino involves grinding the coffee, brewing the coffee, steaming the milk, frothing the milk, and combining the coffee and milk, so more time passes before you get your cappuccino. Figure 1.1 shows this process.
Figure 1.1 For each person in line, the barista is sequentially repeating the same set of instructions (grind coffee, brew coffee, steam milk, froth milk, and combine the coffee and the milk to make a cappuccino).
Figure 1.1 is an example of sequential work, where one task must be completed before the next. It is a convenient approach, with a clear set of systematic (step-by-step) instructions of what to do and when to do it. In this example, the barista will likely not get confused and make any mistakes while preparing the cappuccino because the steps are clear and ordered. The disadvantage of preparing a cappuccino step-by-step is that the barista must wait during parts of the process. While waiting for the coffee to be ground or the milk to be frothed, the barista is effectively inactive (blocked). The same concept applies to sequential and concurrent programming models. As shown in figure 1.2, sequential programming involves a consecutive, progressively ordered execution of processes, one instruction at a time in a linear fashion.