Digital computer systems use binary code in order to operate. In terms of binary form there are only two numbers, zero and one, that represent the sending and receiving of communication signals. There are two categories of digital computer systems, including general purpose and special purpose. The majority of digital computers are general purpose, meaning that they are designed to handle multiple applications and handle a variety of functions.
General purpose digital computer systems include mainframe, super, micro, and mini computers. Those systems that are classified as special purpose are designed for use with one application. Since most computers operate under binary form, almost every system from the desktop PC to the smart phone could be considered to be digital.
Mainframe digital computer systems are large systems that process an enormous amount of data. They are usually stored at a fixed site and are used by companies, such as airlines, that need to store and process huge quantities of data on an ongoing basis. For example, an airline reservation system must handle millions of queries regarding available flights, rates, seating assignments and upgrades. It must also process bookings and constantly update changes to seat availability, cancellations, delays and pricing.
Super computers are considered to be even larger than mainframe systems. They may be used in scientific research or financial analysis. These digital computer systems have the capability of processing the most information in the shortest amount of time.
The most prevalent type of digital computers is micro systems. This category includes personal computers in both desktop and laptop forms. Personal digital assistants (PDA) and handheld computers also fall under the category of micro computer systems. They are versatile and handle a variety of productivity functions and applications.
Desktop and laptop computers typically have the same data processing and storage capabilities. Laptops are popular for their portability. Even though desktop systems are not portable and users usually connect several peripheral devices to them, they are becoming more compact by incorporating the hard drive into the system's monitor. Flexibility has also increased with desktop systems due to wireless and Bluetooth technology. Keyboards, mouses and printers no longer have to be physically connected to a drive through a plug and play or USB cord connection.
Smaller portable computers, such as PDAs and tablet systems have begun to replace laptops. Many of the same capabilities and functions, including Internet access, e-mail communication and business productivity tools are available on these smaller, lightweight systems. Mobile computing devices tend to use wireless technology and are more convenient for traveling due to their substantially smaller size.