Computer Internet Questions and Answers

Answer: C

Correct answer: Modulator demodulator

Modem is a contraction of modulator-demodulator, which names the two operations it performs: putting digital data onto an analogue carrier and taking it off again.

Answer: C

Correct answer: Unsolicited bulk messages sent indiscriminately

Spam is unsolicited bulk email, sent indiscriminately to very large numbers of recipients, usually advertising something or attempting fraud. It is economically viable because the marginal cost of sending a message is essentially zero, so a response rate of one in a million can still pay. That asymmetry - negligible cost to the sender, real cost to every recipient - is the whole of the problem, and it is a direct consequence of SMTP having been designed in an era of mutual trust, with no authentication of the sender. The countermeasures work at several levels: content filtering, often Bayesian, learning what a user treats as spam; blocklists of known senders; rate limiting; and sender verification through SPF, DKIM and DMARC, which let a domain declare which servers may send on its behalf and let receivers check the claim. The name comes from a Monty Python sketch in which the word drowns out all conversation.

Answer: D

Correct answer: Mesh

In a mesh every node has a direct bidirectional link to every other, which gives the greatest reliability at the greatest cost in cabling: n nodes need \( n(n-1)/2 \) links.

Answer: A

Correct answer: PAN

Of the four, only the PAN - personal area network - is a network at all, and it is the smallest of them, covering the space around one person. DSL is an access technology, and RAM and USB are not networks.

Answer: D

Correct answer: in

The top-level domain is the last label, here the country code .in. The .co before it is a second-level domain used for commercial organisations, and example is the name registered beneath it.

Answer: D

Correct answer: Writing a letter

An e-mail is a written message addressed to a particular person and delivered to them, which is what a letter is. The other three produce something to be looked at or heard rather than sent to an address.

Answer: A

Correct answer: FOXPRO

Mozilla, Netscape Navigator and Internet Explorer are all browsers. FoxPro is a database system.

Answer: A

Correct answer: network

A server provides resources to client machines over a network. The clients are what it serves; the network is what connects them.

Answer: D

Correct answer: 1, 3 and 4

Flow control keeps a fast sender from overwhelming a slow receiver, and the three methods are buffering the excess, windowing to limit how much may be outstanding, and signalling congestion avoidance when the receiver falls behind. Cut-through is a switching method, describing when a frame is forwarded, not a means of flow control.

Answer: D

Correct answer: Protocol identifier

Every URL begins with the scheme that says how the resource is to be fetched - http, https, ftp, mailto. That protocol identifier is the one part that is always present; www is merely a common host name and may be absent.