The term, memory, in computing has a lot of confusion surrounding it. People often automatically equate memory with storage, which although technically correct, uses the word memory out of context. Memory, as part of a computer’s specifications, does not relate solely to the amount of storage capacity a computer has. Memory on a computer is not about how many movies, songs or photos it can hold.

Computers require a minimum amount of “memory” or working capacity in order to process information and execute the various programs in use. Thus, the term memory relates both to how much storage memory (See section on ROM below) and also how much random access memory (RAM) a computer has available to engage in processing information.

RAM can be thought of as the platform on which tasks are processed by the machines processor. The processing unit runs the program by fetching the instructions from RAM evaluating the programs in sequence and executing them. In a way, it can be compared to a bridge on a highway where cars are tasks, the motorway’s speed limit is the processor’s speed and the lanes on the motorway are the processor’s speed capability. When traffic converges onto the bridge, if the bridge doesn’t have enough lanes or capacity to deal with the amount of cars (tasks) that the highway is capable of processing then there is going to be a traffic jam. This process is demonstrated in Figs. 5.1 and 5.2.

Adding another lane (RAM memory bank) to the bridge will significantly increase the amount of traffic crossing the river. The processor speed still has a major contribution to the overall processing of tasks. There is no point in having a four-lane bridge on a small highway that has a speed limit of 30 km/h as most of these lanes would be left idle.

When discussing RAM, we considered real-time processing of tasks and how RAM integrates into a computer. The downfall of RAM is that its memory is not persistent through a cut-off of power. As RAM is only capable of storing memory when power is supplied to it, another type of memory is also needed to create a conventional computer. As it would be very inefficient to constantly apply power to the computer to store information that is infrequently accessed and not likely to be modified. Persistent data is needed in computing to store the start-up instructions of a computer, i.e. “boot” the computer. ROM differs from RAM in that its stored data persists even after power is no longer applied to it. Thus, ROM is ideal for use as the computer’s booting memory. ROM is also the type of memory used in hard-drives to store data such as movies, music and documents. The higher the ROM capacity, the greater is the storage capability available in a computer.

The computer’s operating system is the fundamental set of instructions that drives the operation of the computer. It manages all of the computer’s hardware and ties it to the computers software. Technically speaking, the computer’s operating system is software, but it is the main software that interprets all other software.

There are two main types of Personal Computer (PC) operating systems. These are Win and Unix systems. These types of systems are the basis for the Windows and Macintosh (Mac) operating systems, with the Windows operating system being developed by Microsoft and the Mac operating system being developed by Apple.

As illustrated in the diagram below, the operating system for a computer can be interpreted as sitting between the hardware and application software for a computer (Fig. 5.3).

The Apple or “Mac” overall layout, functionality and file structure is different to that of a conventional windows (Microsoft) personal computer. This is not because of the hardware that is used in producing the different machines; it is because of the operating system that they are using.

The operating system in an Apple Mac uses different system architecture than a traditional windows machine and therefore, has different capabilities and ways of doing things. In order to get a better understanding of a computer’s hardware specification, Table 5.2 outlines some perspective, relative to computing technology in 2013.