Utility Software

A utility is a program that performs a task not typically handled by the operating system or that enhances the operating system's functioning. Some of the major categories of utilities include file defragmentation utilities, data compression programs, backup utilities, antivirus programs, and screen savers.

Using a file defragmentation utility like the Disk Defragmenter (built into Windows 95, 98, and 2000), you can rearrange the fragmented pieces of data so your files are stored in contiguous sectors.

Data compression utilities such as WinZip, StuffIT, and others use special algorithms to search files for unnecessary bits, which are stripped out. The process can significantly shrink some types of files. In this collection of compressed files, some files have shrunk by more than 80 percent.

Backup software can help you copy large groups of files from your hard disk to another storage medium, such as tape or a CD-R disk. Many newer operating systems feature built-in backup utilities, but feature-rich backup software is available from other sources. These utilities not only help you transfer files to a backup medium, they also help organize the files, update backups, and restore backups to disk in case of data loss.

A virus is a parasitic program that can delete or scramble files, or replicate itself until the host disk is full. Computer viruses can be transmitted in numerous ways, and users should be especially vigilant when downloading files over the Internet or reusing old diskettes that may be infected. Antivirus utilities examine specific parts of a disk for hidden viruses and files that may act as hosts for virus code. Effective antivirus products not only detect and remove viruses, they also help you recover data that has been lost because of a virus.

Screen savers are popular utilities, although they serve little purpose other than to hide what would otherwise be displayed on the screen. A screen saver automatically displays when the system has been unused for a specified period of time. Screen savers display a constantly moving image on the screen and were originally created to prevent constantly displayed images from "burning" into the monitor. Today's monitors do not suffer from this problem, but screen savers remain a popular utility because they add personality to the user's system.

Unit 5. Processor and Memory cpUs Used in Personal Computers

Since 1978, Intel's processors have evolved from the 8086 and the 8088 to the 80286, 80386, and 80486, and then to the Pentium family of processors (which includes the Pentium, Pentium Pro, Pentium with MMX, Pentium II, Pentium III, Celeron, and Xeon processors). With the Pentium III processor, Intel achieved clock speeds greater than 500 MHz.

Advanced Micro Devices (AMD) was long known as a provider of low-performance processors for use in low-cost computers. That reputation changed in 1998, however, with the release of the K6 line of processors, which challenged Intel's processors in terms of both price and performance. With the K6-III processor, AMD broke the 600 MHz barrier, claiming the fastest processor title for the first time in IBM-compatible computers.

Cyrix began as a specialty chip maker but eventually began producing microprocessors including the MediaGX processor and now the MII series of processors.

Motorola makes the CPUs used in Macintosh and PowerPC computers. Macintosh processors use a different architecture than IBM-compatible PC processors.

PowerPC processors are RISC processors. Instruction sets for RISC processors are kept smaller than those used in CISC chips. This smaller size enables the processor to run faster and process more instructions per second. RISC processors are found in Apple microcomputers, some workstations, and many minicomputers and mainframe systems. They are also the basis for many small digital devices, such as H/PCs.