X. Listening and Comprehension.

Ex. 13. Listen to the text “PC and Microcomputer”. Cross out sentences given below which don’t correspond to the contents of the text.

Pc and microcomputer

The personal computer can serve as a work station for the individual today. Moreover, as it has become financially feasible to provide a computer for the individual worker, so also technical developments have made the interface between man and machine increasingly “friendly”, so that a wide array of computer functions are now accessible to people with no technical background.

A personal computer is a small computer based on a microprocessor; it is a microcomputer. Not all computers, however, are personal computers. A microcomputer can be dedicated to a single task such as controlling a machine tool or metering the injection of fuel into an automobile engine; it can be a word processor, a video game or a “pocket computer” that is not quite a computer. A personal computer is something different: a stand-alone computer that puts a wide array of capabilities at the disposal of an individual.

The first generation of true personal computers, which came on the market between 1977 and 1981, had eight-bit microprocessors; later introduced systems had 16-bits ones. Now 32-bit microprocessor chips are available, and soon they will be included in complete computer systems.

1. Performance of a wide array of computer functions.

2. Accessibility of PC for not professionals.

3. A microprocessor-based PC.

4. The operation of a microprocessor.

5. Comparison of a microcomputer and a PC.

6. Microprocessor’s capacity.

7. Microcomputer software.

8. The cost of a microcomputer.

XI. Reading and Translation.

Exercise 14. Read and Translate the text “Mini PC”.

Mini pCs

Recent improvements in large-scale integration and power-semiconductor technology have yielded compact PCs that can be used economically for controlling simple machines and processes. A number of companies are now producing the so-called mini PCs.

Mini PCs generally are classified as those that can economically replace as few as four relays. They provide timer and counter functions as well as relay logic, and typically are small enough to fit comfortably in a 19-in.rack. Most minis have less then 32 I/0s are ports, but some are expandable to drive up to 400 I/0s devices. The I/0s are usually digital, but analog I/0 are available. These make possible control of pressure, temperature, flow and other analog functions.

Some mini PCs are self contained, with the processor and a means for mounting numerous I/0 modules. Thus, modular mini’s are readily expandible. Some self-contained units are expandible, some are not.

Mini PCs often cost more than relays they replace, but installed cost of a mini is generally comparable to and sometimes less than a corresponding relay panel. The reason is that the mounting and wiring of a PC is much simpler than the mounting and wiring of corresponding relays. And the PC often occupies less space.

PCs, moreover, perform some functions that are not typically provided by relays but associated drum controllers, counters, specialty timers, and other complex-function panel components.

Many mini PCs are capable of controlling remote printers or of communicating with other PCs or a host computer. These capabilities make possible data collection and coordination with associated machines.

Most minis are preprogrammed to be self checking. Processors, I/0s, and programming devices are routinely checked for faulty operation. LEDs on the front of the PCs identify problem areas. In addition PCs can be programmed to diagnose and identify faults in limit switches, transducers, relays, motor startes, and similar peripheral components. These diagnostic capabilities reduce maintenance and down-time costs.