*:48 Electronic Mail and Computer Mediated Communication

Exam 1997-11-20 with solutions

You can submit the exam in Swedish or English, but if you want the text of the exam questions in English, you should notify Jacob Palme at least two weeks in advance. Examen på svenska på andra sidan.

Please write your e-mail address on the outside of the folder with your exam.

Allowed documents during the exam: Ordinary language dictionaries to and from Sweden and English.

To pass this exam, you will have to have a certain minimum number of points separately on question 1-2 and on question 3-4.

Carefully read the questions and check that your answer is really an answer to the question. As an example, in one exam a question was "Describe important characteristics with non-simultaneous computer conferencing systems, and which makes them different from electronic mail systems". One student gave a thorough description of the differences between computer conferencing and face-to-face meetings. Such an answer will regrettably give no points at all!

This exam is for 3.5 points. Those who have enrolled in thus course segment in 1996 or earlier, can choose to take the course as it was specified then, by only answering question 2-4 in the exam and only getting 2.5 points. If this is the case, write this very clearly as an answer to question 1 of the exam.

If you have earlier passed the course INT2, you shall only reply to question 3-4 and will only get 2 points in this exam. If this is the case, specify this clearly as your answer to question 3-4 in the present exam.

No. Question Max. score

1 Which technical problems can occur if several people at different computers are to change the same data at the same time? What can be done to handle these problems? 6

Suggested reply:
Problems: If both get a copy and modify it and save the change, only the last of the changes may get saved. One person cannot see what another person has simultaneously changed.
Solutions: Locking of a whole document or part of it, such as a paragraph, line or record. Merging of two parallel changes of the same item. Synchronisation of screens so that all see every change made by any of the other simultaneous updaters immediately.

2 In which of the following cases would electronic mail be a suitable medium? Give reasons for your answers with pros and cons of using e-mail in each case.
a. Exchange of experience between salesmen regarding the sale of a new product.
b. Discussions of whom of several applicants for a position should is most suitable.
c. Planning a revolution (coup d'état)
6

Suggested reply:
a. E-mail is good for experience exchange, especially between people who have difficulty meeting at the same time and place.
b. Security problems with sensitive personal information, may also be in conflict with data integrity legislation, difficult decisions difficult to make via e-mail.
c. Security problems, evidence in computers may be retrieved by the police. But an advantage with computers if good security measures might be that police can not as easily see who is meeting with whom as with F2F meetings.

3 Why is a hierarchical structure used in specifying domain names? 6

Suggested reply:

Because it allows decentralising of the task of giving out new globally unique names.
Because it makes searches for entries in decentralised directory data bases (DNS) easier.
Because such names are easy to understand for humans.

4 SMTP uses many small steps of interactions back and forward between two computers. This can make communication slow. Is there any method available to overcome this problem? 6

Suggested reply:
Send all the SMTP commands without waiting for response, and collect the responses as they come in. This technique is called command pipelining and ESMTP allows units communicating to indicate its use. Without ESMTP, it is technically not allowed, but often works also in that case.

Scoring limits

Points	SU score	KTH score
0-9	Not passed (U)	Not passed
10-13	Passed (G)	3
14-16	Passed (G)	4
17-24	Passed with distinction (VG)	5

No.	Question	Max. score

1	Which technical problems can occur if several people at different computers are to change the same data at the same time? What can be done to handle these problems?	6
	Suggested reply: Problems: If both get a copy and modify it and save the change, only the last of the changes may get saved. One person cannot see what another person has simultaneously changed. Solutions: Locking of a whole document or part of it, such as a paragraph, line or record. Merging of two parallel changes of the same item. Synchronisation of screens so that all see every change made by any of the other simultaneous updaters immediately.
2	In which of the following cases would electronic mail be a suitable medium? Give reasons for your answers with pros and cons of using e-mail in each case. a. Exchange of experience between salesmen regarding the sale of a new product. b. Discussions of whom of several applicants for a position should is most suitable. c. Planning a revolution (coup d'état)	6
	Suggested reply: a. E-mail is good for experience exchange, especially between people who have difficulty meeting at the same time and place. b. Security problems with sensitive personal information, may also be in conflict with data integrity legislation, difficult decisions difficult to make via e-mail. c. Security problems, evidence in computers may be retrieved by the police. But an advantage with computers if good security measures might be that police can not as easily see who is meeting with whom as with F2F meetings.
3	Why is a hierarchical structure used in specifying domain names?	6
	Suggested reply: Because it allows decentralising of the task of giving out new globally unique names. Because it makes searches for entries in decentralised directory data bases (DNS) easier. Because such names are easy to understand for humans.
4	SMTP uses many small steps of interactions back and forward between two computers. This can make communication slow. Is there any method available to overcome this problem?	6
	Suggested reply: Send all the SMTP commands without waiting for response, and collect the responses as they come in. This technique is called command pipelining and ESMTP allows units communicating to indicate its use. Without ESMTP, it is technically not allowed, but often works also in that case.