1331.0 - Statistics - A Powerful Edge!, 1996
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 31/07/1998
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DATA AND COMPUTERS
The electronic computer was introduced to the Australian business community and the world in the 1960s. It was only gradually adopted, as early models were very expensive and slow, and there was little expertise available. Commercial computing skills were not taught at university, and business software applications could not be bought, but had to be developed in-house by programming staff. Good programmers were scarce and expensive. The following table shows development of computer usage in the ABS, which mirrored a growing use of computers in the large business community.
COMMERCIAL COMPUTER INSTALLATIONS Large companies don’t have just one large computer, but usually a network of specialist computers. Depending on company size, there could be one or two very powerful mainframe computers, a number of small, medium and large Unix based mid-range computers, and individual PCs for all staff who work with information. These computers are networked together. The network connecting the computers in any one location is usually referred to as a Local Area Network (LAN), while all the individual LANs are connected together by a Wide Area Network (WAN). Using this network, authorised personnel can access data and make use of computer facilities anywhere in the system. Until about 10-15 years ago, the mainframe was the most common sort of computer in business. Mainframe computers today typically run older computer applications (often called “legacy” systems) written a few years ago; and also applications which require the highest levels of reliability, security and processing power. If the highest performance is not required, these days corporations often find it easier and more economical to use mid-range computers, usually running under the Unix operating system. Regardless of the type of large computer being used, users interact with their computer systems, and obtain data using their desktop or notebook PC. THE INTERNET and INTRANETS Businesses, academic institutions and people at home use the Internet to send E-mail messages around the world or to assist in research. However, most businesses consider that the Internet is too slow, unreliable and not secure enough for widespread internal use. To solve this problem, they set up their own private internal Internets, known as Intranets. This gives them the ease of use and convenience of the Internet, but with the performance and security of an in-house system. Intranets can be connected to the public Internet via secure gateways, which have “firewalls” to prevent unwanted external access to internal systems. COMPUTER HARDWARE To function properly, a computer system needs the following hardware components: An input device allows a user to enter data or program the computer. The processing unit controls all activities within the system. Data Storage holds databases, files and programs. Output devices present the finished information product to the user.
Processing unit. The Central Processing Unit (CPU) is the heart of a computer system. In most modern computers the CPU consists of just one or two silicon chips that are small enough to hold in one hand, but which contain many millions of logic circuits. A CPU would typically execute millions of instructions per second. Associated with the CPU is the read access memory (RAM) memory. The RAM has to be big enough to hold all programs and data that are being worked on at a given time. RAM size ranges from a few million bytes to a few hundred million bytes. Data storage. Disk drives are used on almost all computers to hold data. A current PC might have one 2.0 GB disk drive (two billion bytes), while large computers might have a number of disk drives holding tens or hundreds of GB. Data can be copied onto magnetic tapes or CD-ROMs for backup, transfer between computers, or long term storage. A CD-ROM can hold 600 MB, while tape units can range from about 500MB to 24GB. Data can also be copied onto Diskettes (floppy disks), but their small size (1.44MB) limits their usefulness with large data sets. Output devices. Output devices include video monitors, various sorts of printers, magnetic disks and tapes, CD-ROMs, data communication and phone lines, and stereo speakers. Computers can also be used to drive industrial processes, control chemical plants, and lock/unlock security doors. Modern car engine management systems, office lifts, VCRs, and numerous other domestic and industrial systems are now controlled by miniature computer systems. STORAGE AND RETRIEVAL Much of the computer’s power comes from its ability to store, sort and classify data. Over the past few years, disk systems have become very cheap and reliable, and it is now possible to obtain disk systems that will store billions of bytes of data for just a few hundred dollars. This thousand-fold drop in data storage price, and the development of sophisticated database systems has greatly improved the usefulness of computers. It is now possible to hold all company information, going back for years, on a computer. Laws are being changed to drop the legal requirement for paper storage. SOFTWARE There are two basic types of computer software: systems software which controls the operation of the computer, and applications software which performs useful tasks for the user. Computers are purchased in order to run the application software, while system software assists to make this job easy and convenient. Systems software: is dividied into two classes, operating systems and tools and utilities. An operating system typically has two levels: The lower level basic input-output system (BIOS) controls the most basic functions, such as: reading and writing RAM (memory), and input to and output from peripherals such as mouse, keyboard, printer and screen. The higher level main operating system (eg Windows) acts as a platform to host programs. It provides the user interface to control the computer’s operation, and the environment to effectively operate application software. For example, it provides a file sub-system with its structure of drive names, directories, folders, files, and indexes; and file handling facilities such as creating, copying and deleting. Typical operating systems are DOS, Unix, Mac OS and Windows 98. Mac OS and Windows 98 have a “user friendly” Graphical User Interface (GUI) which enables computer control by means of windows, menus, icons and a mouse. DOS and UNIX require the user to type precise commands, which can be hard to remember. Windows 98, Mac OS and Unix can run many programs at one time (multiprogramming), which makes for more efficient computer hardware use and user convenience. Tools and utilities are usually necessary to make productive use of a computer. Some are provided with the operating system and others are purchased separately. Typical system utilities are Internet browsers, anti-virus software, program compilers, editors and file backup systems. Applications Software can also be divided into two classes: personal productivity tools and other computer applications. Personal productivity tools are commercial products designed to handle standard computing tasks such as word processing, numerical analysis, data manipulation and storage, and data presentation. Typical products are:
Other Computer Applications: The above “personal productivity tools” are commonly used by most computer users at home, school and in the office. They are fairly cheap and available on many computers. However, businesses and organisations usually buy computers to automate major business functions, and this is not usually done on personal productivity software. Some software applications can cost many thousands of dollars to buy or develop, while a major banking or airline reservation system could cost millions. Application software can either be purchased “off the shelf” or developed for a specific purpose. An accounting package is a typical example of a purchased application, while a system to handle parking fines might be designed and written from scratch. A database application could be used for retail stock control: recording sales and setting up replacement orders. An airplane’s autopilot navigation system is an example of software that receives information (eg. compass heading and global positioning system [GPS] position) and outputs data that controls rudder and flap hydraulics which adjust the course. If it is decided to develop software to automate a task, the work is done by systems analysts and programmers. SYSTEMS ANALYST System analysis is the process of breaking down a data processing problem into functional components to determine the best method of handling the problem. The systems analyst must, with consultation:
PROGRAMMER Programming is the process of producing a set of instructions to make a computer perform a specified activity. The programmer takes system analysis results and develops computer programs to solve the problem. A programmer must:
USER The user is the final judge of whether a computer system is meeting the needs it was designed to fulfil. The better the link between automated system component and user, the more likely it is that the system will be effective. Modern system designers consult widely with the user in order to design systems that meet user needs, and put considerable effort and ingenuity into designing the interface between a system and its users.
EXERCISES
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