CLASSIFICATION OF OUTPUT DEVICES

CLASSIFICATION OF OUTPUT DEVICES

Based on the hard copy and soft copy outputs, the output devices are classified into: hard copy and soft copy output devices. Printers, plotters, and microfilms are the most commonly used hard copy output devices while monitors, voice response systems, projectors, electronic whiteboards, and headphones and headsets are some commonly used soft copy output devices 

Figure 7.3. Classification of Output Devices

TYPES OF RAM

There are two types of random access memory, which are as follows:

• Static RAM (SRAM): This RAM retains the data as long as power is provided to the memory chip. It need not be 'refreshed' (pulse of current through all the memory cells) periodically. It is very fast but much more expensive than DRAM. SRAM is often used as cache memory due to its high speed.
• Dynamic RAM (DRAM): This RAM, unlike SRAM, must be continually refreshed to maintain the data. This is done by placing the memory on a refresh circuit that rewrites the data several hundred times per second. DRAM is used for most system memory because it is cheap and small 

Web crawler

A Web crawler is an Internet bot that systematically browses the World Wide Web, typically for the purpose of Web indexing.

A Web crawler may also be called a Web spider, an ant, an automatic indexer, or 

(in the FOAF software context) a Web scutter.

Web search engines and some other sites use Web crawling or spidering software to update their web content or indexes of others sites' web content. Web crawlers can copy all the pages they visit for later processing by a search engine that indexes the downloaded pages so that users can search them much more quickly.

Crawlers can validate hyperlinks and HTML code. They can also be used for web scraping (see also data-driven programming).

Web crawling

A Web crawler starts with a list of URLs to visit, called the seeds. As the crawler visits these URLs, it identifies all the hyperlinks in the page and adds them to the list of URLs to visit, called thecrawl frontier. URLs from the frontier are recursively visited according to a set of policies.

The large volume implies that the crawler can only download a limited number of the Web pages within a given time, so it needs to prioritize its downloads. The high rate of change implies that the pages might have already been updated or even deleted.

The number of possible crawlable URLs being generated by server-side software has also made it difficult for web crawlers to avoid retrieving duplicate content. Endless combinations of HTTP GET(URL-based) parameters exist, of which only a small selection will actually return unique content. For example, a simple online photo gallery may offer three options to users, as specified through HTTP GET parameters in the URL. If there exist four ways to sort images, three choices of thumbnail size, two file formats, and an option to disable user-provided content, then the same set of content can be accessed with 48 different URLs, all of which may be linked on the site. This mathematical combination creates a problem for crawlers, as they must sort through endless combinations of relatively minor scripted changes in order to retrieve unique content.

Computer Network Part-2

6.

A communications device that combines transmissions from several I/O devices into one line is a

1)	concentrator
2)	modifier.
3)	multiplexer.
4)	full-duplex line.

7.

Sending a file from your personal computer's primary memory or disk to another computer is called

1)	uploading
2)	downloading
3)	logging on
4)	hang on

8.

What is the name of the software package that allows people to send electronic mail along a network of computers and workstations?

1)	Memory resident package
2)	Project management package
3)	Data communication package
4)	Electronic mail package

9.

The communication mode that supports two-way traffic but only one direction at a time is

1)	simplex
2)	duplex
3)	half duplex
4)	multiplex

10.

HMP (Host Monitoring Protocol) is:

1)	a TCP/IP protocol used to dynamically bind a high level IP Address to a low-level physical hardware address
2)	a TCP/IP high level protocol for transferring files from one machine to another
3)	a protocol used to monitor computers
4)	a protocol that handles error and control messages

Computer Networks Part-1

1. Error detection at a data link level is achieved by   1) bit stuffing 2) cyclic redundancy codes 3) Hamming codes 4) equalization 2. When the computer provides the manager with a multiple choice of possible answers, the prompting technique is   1) question and answer 2) form filling 3) open-ended question 4) menu selection 3. Which data communication method is used to transmit the data over a serial communication link?   1) simplex 2) half-duplex 3) full-duplex 4) None of above 4. What is the minimum number of wires needed to send data over a serial communication link layer?   1) 1 2) 2 3) 4 4) 6 5. Most data communications involving telegraph lines use:   1) simplex lines 2) wideband channel 3) narrowband channel 4) dialed service

IBPS Specialist Officer Exam Questions..Very Important Part-4

Question 1:

Which data communication method is used to transmit the data over a serial communication link?

a. simplex

b. half-duplex

c. full-duplex

d. b and c

e. None of above

Question 2:

What is the minimum number of wires needed to send data over a serial communication link layer?

a. 1

b. 2

c. 4

d. 6

e. none of above

Question 3:

Which of the following types of channels moves data relatively slowly?

a. wide band channel

b. voice band challen

c. narrow band channel

Question 4:

Most data communications involving telegraph lines use:

a. simplex lines

b. wideband channel

c. narrowband channel

d. dialed service

Question 5:

A communications device that combines transmissions from several I/O devices into one line is a 

a. concentrator

b. modifier

c. multiplexer

d. full-duplex line

Question 6:

How much power (roughly) a light emitting diode can couple into an optical fiber?

a. 100 microwatts

b. 440 microwatts

c. 100 picowatts

d. 10 miliwatts

Question 7:

The synchronous modems are more costly than the asynchronous modems because

a. they produce large volume of data

b. they contain clock recovery circuits

c. they transmit the data with stop and start bits

d. they operate with a larger bandwidth

e. none of above

Question 8:

Which of the following statement is correct?

a. terminal section of a synchronous modem contains the scrambler

b. receiver section of a synchronous modem contains the scrambler

c. transmission section of a synchronous modem contains the scrambler

d. control section of a synchronous modem contains the scrambler

e. none of the above

Question 9:

In a synchronous modem, the digital-to-analog converter transmits signal to the 

a. equilizer

b. modulator

c. demodulator

d. terminal

e. none of aobve

Question 10:

Which of the following communications lines is best suited to interactive processing applications?

a. narrow band channel

b. simplex lines

c. full duplex lines

d. mixed band channels

Answers

 ---------------------

1. c

2. b

3. c

4. c

5. c

6. a

7. b

8. c

9. a

10. c