1. A section of the computer which accepts information from outside the computer.
2. Device or devices which put out information of the computer.
3. Storage devices accepting information at a very high speed from the computer and releasing information at the proper speed for the peripheral equipment.
Ex. 9. Find in the text the sentences with Infinitive. Define its function and translate it.
IV. Comprehension
Ex. 10 Agree or disagree with the following statements.
1. To be accepted by the machine, information for a digital computer has to be in the form of symbols.
2. The input unit makes possible communication from the other data-handling equipment and human being to the computer.
3. The output of a computer is known to vary according to the receiving of the information.
4. All peripheral equipment is slow as compared with, the computer.
5. The computer can easily put out information in a form acceptable to human beings.
6. A human being is known to write by hand at the rate of about 100 words per minute.
7. The characters are regularly expressed for the computer's purposes as six or seven 1’s and 0’s.
Ex. 11 Answer the following questions:
1. What is the general purpose of the input unit?
2. How may the 1’s and O's be expressed for the computer?
3. What is the general purpose of the output unit?
4. What does the peripheral equipment consist of?
5. What is the general purpose of a buffer?
6. What is the ratio between a computer's speed and the top output speed of a human being?
7. How are input and output devices usually called?
Ex. 12 Make up the plan of the text.
V. Oral practice
Ex. 13. Prove the communication ability of the computer.
Ex. 14 Compare computer with other peripheral devices.
Ex. 15. Speak on the topic “Input and output unit” using the plan from Ex.11
V. Reading and comprehension.
Ex. 16 Read the text “Disk Buffers” and discuss the following problems in group:
a) In what way can a change in disk buffer size affect disk I/O times?
b) What factors can interact to cause disk delays?
Disk Buffers
Microcomputer systems that process large and complicated files often spend considerable time reading from, and writing, mass storage devices. This operation creates long processing pauses that annoy end users. By simply enlarging the PC-DOS/MS-DOS disk buffer setting from its normal default value of 2, you can dramatically reduce disk I/O delays.
A disk buffer is a block of main memory in which the DOS holds data that is being read from or written to a disk. Each time DOS is requested to read or write a record, it first looks to see whether the sector containing that record is already in a buffer. By increasing the size of the disk buffer, the more likely it is that sought-after data will be in main memory. If it is, then DOS simply transfers the record to the application without the need to read the data from the disk which, of course, saves time.
The logical solution would seem to be to move all the data used, by an application into the disk-buffer area. Unfortunately, microcomputer systems are not blessed with huge blocks of main memory and a compromise must be made between the amount of memory used for disk buffering and the main memory required for other system operations.
Many factors interact to cause disk delays (including facets of the specific hardware configuration and operating system), they cannot be derived theoretically. Instead, they must be measured empirically using the actual system configuration, operating system and "typical" disk transactions made in actual applications.
Measuring something as complicated as the timing of Disk I/O in a microcomputer system requires a system model.
Ex. 17 Read and translate the text:
WHAT EQUIPMENT IS REQUIRED?
To run word-processing software, you must, of course, have a computer. If the computer does not come with a display screen, you will need a separate screen. Most word-processing software comes on disks, so a disk drive is required. It's also good to have a couple of blank disks, in case you want to save something that you have written. And if you want to put what you've written on paper, you'll need a printer.
Word-processing software works like any other computer program—you simply load the program into your computer. Then you type on the computer keyboard just as you would type on a typewriter. As you type, the words appear on the screen. The words that you type are also stored in the computer's memory, so you can save your writing on a disk and work on it later, just as you can save a computer program on a disk and run or change it later. If you have a printer, you can print your writing on paper in much the same way that you print the output from the computer on paper. In fact, you can print as many copies of your work as you like without having to retype it.
Before you use a word processing program, you should read the documentation carefully in order to determine exactly what that particular program does and exactly what you have to do to run it. Most word-processing programs perform the same basic functions.
Unit 11
Computer networks
I. Language.
