INFORMATION TECHNOLOGY INFRASTRUCTURE

COMPUTER HARWARE

Today's computer systems have six major components: the central processing unit (CPU), primary storage, secondary storage, input technologies, output technologies, and communications technologies. The CPU is made up of the arithmetic-logic unit that performs the calculation, the registers that stores minute amount of data and instructions immediately before and after processing, and the control unit that controls the flow of information on the microprocessor chip. Microprocessor designs aim to increase processing speed by minimizing the physical distance that the data (as the electrical impulses) must travel, and by increasing the bus width, clock speed, word length and number of transistors on the chip.

There are four types of primary storage: registers, random access memory (RAM), cache memory, and read-only memory (ROM). All are direct access memory; only ROM is nonvolatile. Secondary storage includes magnetic media (tapes, hard drives and diskettes) and optical media (CD-ROM, DVD, FMD-ROM and optical jukeboxes)

Primary storage has much less capacity than secondary storage and is faster and more expensive per byte stored. Primary storage is located much closer to the CPU than is secondary storage. Sequential-access secondary storage media such as magnetic tape is much slower and less expensive than direct access media (hard drives, optical media).

An Enterprise storage system is an independent, external system with intelligence that includes two or more storage devices. There are three major types of enterprise storage subsystems: redundant arrays of independent disks (RAIDs), storage area networks (SANs) and network-attached storage (NAS). RAID links group of standard hard drives to a specialized microcontroller. SAN is architecture for building special, dedicated networks that allow access to storage devices by multiple servers. A NAS device is a special purpose server that provides file storage to users who access the device over a network.

Supercomputers are the most powerful, designed to handle the maximum computational demands of science and the military. Mainframes are not as powerful as supercomputers, but are powerful enough for use by large organizations for centralized data processing and large databases. Minicomputers are smaller and less powerful versions of mainframes, often devoted to handling specific subsystems. Workstations are in between minicomputers and personal computers in speed, capacity and graphics capability. Desktop personal computers (PCs) are the most common personal and business computers. Network computers have less computing power and storage, relying on a connection to a network for communication, data, processing and storage devices.

Laptop or notebook computers are small, easily transportable PCs. Palmtop computers are handheld microcomputers, usually configured for specific applications and limited in the number of ways they can accept user input and provide output. Wearable computers worn on the user's clothing, free their users' movements. Embedded computers are placed inside other products to add features and capabilities. Employees may wear active badges as ID cards. Memory buttons are nickel-sized devices that store a small database relating to whatever it is attached to. Smart cards contain a small processor, memory and an input/output device that allows them to be used in everyday activities such as personal identification and banking.

Principal input technologies include the keyboard, mouse, trackball, touch screen, stylus, joystick, ATM, POS terminal, bar-code scanner, optical mark reader, optical character reader, handwriting and voice recognition systems, sensor, microphone and camera. Common output technologies include the monitor, impact and nonimpact printers, plotter, voice output, multifunction devices and multimedia.

Multimedia computer systems integrate two or more types of media, such as text, graphics, sound, voice, full-motion video, images and animation. They use a variety of input and output technologies, often including microphones, musical instruments, digitizers, CD-ROM, magnetic tape and speakers. Multimedia systems typically require additional processing and storage capacity.

According to Moore's Law, microprocessor capability increases ever more rapidly. Miniaturization is also increasing. These advancements usher in new generations of faster, more powerful, and more compact computers, as well as new generations of microcontrollers. Organizations must continually appraise the issue of productivity work styles, new product and services, and improves communications against these new options. Adoption decisions are difficult because of heavy past, current and future investment.

COMPUTER SOFTWARE

Software consists of computer programs (coded instructions) that control the functions of computer hardware. There are two main categories of software: systems software and application. Systems software manages the hardware resources of the computer system and functions between the hardware and the application software. Systems software includes the system control programs (operating system) and the system support programs. Application software enables users to perform certain tasks and information-processing activities. Application software may be proprietary or off-the-shelf.

Operating systems manage the actual computer resources (i.e. the hardware). Operating systems schedule and process applications (jobs), manage and protect memory, ensure cache consistency, manage the input and output functions and hardware, manage data and files and provide clustering support, security, fault tolerance, interapplication communications, graphical user interfaces and windowing.

There are five types of operating systems: mobile, desktop, departmental, enterprise and supercomputer. Mobile device operating systems are designed to support a single person using a mobile, handheld device and information appliance. Desktop operating system has the least functionality and enterprise operating systems the most, with departmental operating system in the middle. Desktop operating systems are typically designed for one user, departmental operating systems for up to several hundred users and enterprise operating system can handle thousands of users and millions of transactions simultaneously. Supercomputer operating systems are designed for the particular processing needs of supercomputers.

Proprietary software can be developed in-house to address the specific needs of an organization. Existing software programs can be purchased off the shelf from vendors that sell programs to many organizations and individuals. Or a combination of these two methods can be used, by purchasing off-the-shelf programs and customizing them for an organization’s specific needs.

The major types of application software are spreadsheet, data management, word processing, desktop publishing, graphics, multimedia, communications, speech recognition and groupware. Software suites combine several types of application software (e.g. word processing, spreadsheet and data management) into an integrated package.

Software and programming languages continue to become more user oriented. Programming languages have evolved from the first generation of machine languages that is directly understandable to the CPU to higher levels that use more natural languages and that do not require users to specify the detailed procedures for achieving desired results. This trend ensures that the end users and the information systems staff will become more productive. In addition, software is becoming much more complex, expensive and time consuming to develop. As a result the trend is toward purchasing off-the-shelf software, often in the form of components, rather than developing it in-house. In the future, organizations will tend to buy component-based software modules to reduce cost and development time.

Organizations want packaged applications that support integration between functional modules (i.e. human resources, operations, marketing, finance, accounting etc.) that can be quickly changed or enhanced, and that present a common graphical look and feel. In addition organizations want individual components –software modules- that can be combined as necessary to meet changing business needs. Enterprise software consists of programs that manage a company’s vital operations, such as logistics-coordination, inventory replenishment, ordering, supply-chain management, human resource management, manufacturing, operations, accounting and financial management.