2. The Context of Cybersecurity: Cyberspace 27 Before the high-performing and ubiquitous Internet of today, people worked offline most of the time. They purchased software programs on CDs (and before that, floppy disks) and installed programs locally on their computers. These programs were known as desktop applications. The Microsoft Office Suite of programs, which includes Word, Excel and PowerPoint, are examples of popular desktop applications still in use today. Desktop applications are similar to the apps that we use on our tablets and smartphones. One major difference, however, is that most apps are dependent on Internet connectivity. In fact, they are essentially specialized web browsers. This is important for computing devices with small, touch-enabled screens because apps can deliver custom content more effectively than smartphone web browsers—that is why the app paradigm is much more popular on smartphones than on laptops. Web browsers are a desktop application that come pre-installed on our OSs, although many people use their pre-installed browsers to download alternative web browsers that they prefer. Web browsers are the main desktop application we use. They are our window into the data we access and the applications we use in the cloud. Online applications are called browser-based applications. Browser-based applications have several advantages over desktop applications. For one, information processing takes place on cloud servers, not on our local computers. This means it is not necessary for our computers to have a lot of processing power and memory. Also, our data is stored online and is accessible from any Internet-connected computer. We do not have to keep track of and synchronize data stored on multiple different local computers (e.g., our home computer and work computer). Nor do we have to worry about backing up our data to protect it from accidental loss—these were major issues before cloud computing. One downside of this data storage model, however, is that we are no longer the sole stewards of our data. We are trusting our data to an outside organization and this raises privacy concerns (more on this in Chapter 9). Also, being online makes our data an attractive and accessible target to hackers all over the world, raising much more serious privacy concerns! 2.3.5 Virtual Machines “Welcome my son / Welcome to the machine / What did you dream? / It’s alright, we told you what to dream.” - “Welcome to the Machine” lyrics by Pink Floyd Traditionally, a one-to-one correspondence has existed between physical computers and operating systems (OSs). A computer has one set of hardware, and the one OS mediates access to that hardware. Virtual machines (VMs) break this paradigm. A VM is an OS that runs as a program on top of a computer’s actual OS. This technology is called virtual machines because it enables users to allocate virtual hardware to OSs. This makes it possible to run multiple OSs on a single computer —even different kinds of operating systems. When a computer is running VMs, the actual OS is called the host OS and the VMs are called guest OSs. There is a limit to how many guest VMs can run on a single computer because virtual CPUs and RAM assigned to VMs ultimately run on physical
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