After the last storm the computer that used to act as this blog storage server gave up the ghost.
That means that the copies of laboratory exercises and course slides are gone too. Together with many of the documents referenced in this blog. I am not planning on restoring either the contents or the server anytime soon.
However, I will be posting each new document on the "private" PoliformaT site.
I have to let this blog go
I want to welcome all the new students. This blog has been the home for the English language class of the subject RED (code 5662). The format was simple (and sometimes even Internet Explorer rendered it properly) and you needed no silly authorization to download anything. However, the UPV in its infinite wisdom has decided to curtail the use of external tools, like this blog, in favor of their locally cooked version of Sakai they have named PoliformaT.
It seems that faculty not using this tool will be considered as doing no work on cyberspace. There is some money involved, don't get me wrong, we have a job to do and some money to make. By putting the carrot on the use of PoliformaT they are insuring all of us will end up using that platform whether it fits our (or your) needs or not.
For our English group it has been a constant cause of trouble the fact that students join us a bit later than the beginning of the term. Because of the involved paperwork, they use to come to the class sooner than they have got a username and password. Under the university instituted systems (so called microwebs and now PoliformaT) they have no access to course syllabus or slides. To address this problem I have been using for two years this blog (the fact blogger interface was cooler and simpler than the local alternatives did help too).
So from here I want to apology in advance for the possible trouble you are facing with this new move at the UPV. While technically I cannot claim this is censorship I would say they are giving as the same choice that Ford Motor Company gave to T-model customers: "You can choose any color you like as long as it is black".
It seems that faculty not using this tool will be considered as doing no work on cyberspace. There is some money involved, don't get me wrong, we have a job to do and some money to make. By putting the carrot on the use of PoliformaT they are insuring all of us will end up using that platform whether it fits our (or your) needs or not.
For our English group it has been a constant cause of trouble the fact that students join us a bit later than the beginning of the term. Because of the involved paperwork, they use to come to the class sooner than they have got a username and password. Under the university instituted systems (so called microwebs and now PoliformaT) they have no access to course syllabus or slides. To address this problem I have been using for two years this blog (the fact blogger interface was cooler and simpler than the local alternatives did help too).
So from here I want to apology in advance for the possible trouble you are facing with this new move at the UPV. While technically I cannot claim this is censorship I would say they are giving as the same choice that Ford Motor Company gave to T-model customers: "You can choose any color you like as long as it is black".
September marks
!!! I am glad to inform you that after marking the exams all of you have passed the subject. Details can be found on the usual place.
Next September 11th
Those of you who haven't pass the subject yet do not forget exam will be held September 11th, at 4:00pm.
Course Marks available
On our usual place in the "exams" tab.
Results are quite disappointing as several people did not show up for the exam. Others did but failed the subject by not scoring good enough. Most of you did pass, for those of you, congratulations.
Those who did not pass the subject, please think whether you could have done better by turning in any of the assignments, showing up for the lectures more often, doing the lab exam and, perhaps, studying a bit more.
Anyway, you are welcome to review your exam so you see for yourself what was wrong. Drop me an email for a reviewing appointment.
Solved exam is now available.
Results are quite disappointing as several people did not show up for the exam. Others did but failed the subject by not scoring good enough. Most of you did pass, for those of you, congratulations.
Those who did not pass the subject, please think whether you could have done better by turning in any of the assignments, showing up for the lectures more often, doing the lab exam and, perhaps, studying a bit more.
Anyway, you are welcome to review your exam so you see for yourself what was wrong. Drop me an email for a reviewing appointment.
Solved exam is now available.
Graded assignments
All the assignments turned in have been graded. Please go to the attendance/marks page to check yours.
Weekend reading
I mentioned today in the class I will post this article on one of the many network security battles. I guess the printer friendly version will remove most of the annoying advertising from the web page (but I was not sure the server would be happy about my referencing of a printer friendly page).
It seems that another one bites the dust in terms of getting their encryption system hacked (not that I am interested or worried as I do not have either content or player for that format).
It seems that another one bites the dust in terms of getting their encryption system hacked (not that I am interested or worried as I do not have either content or player for that format).
Fourth assignment
It's only one month left so here is the last assignment for you. Please note its due date is May 28th.
Some people's comments about IPv6
Slashdot was publishing a note about the use of IPv6 in space. Some people found this an opportunity to voice their opinion about IPv6.
All you wanted to know about bit error rate but were afraid to ask
One important detail about BER (bit error ratio) is that it is an average value. If you use it as such there is no problem. But for if you have link whose BER=10^-4 and you transmit 10000 bits over that channel it is likely you won't get any error at all. The reason is that BER is an statistic but not a RULE.
If you want to learn more abot what this means, read on this interesting but yet accessible document.
If you want to learn more abot what this means, read on this interesting but yet accessible document.
Computer Networks by Andrew S. Tanembaum
It seems the book is also available for campus-wide access in electronic format (part of the O'Reilly Safari Books on-line package) so as far as you are part of the campus network either connected locally or by a VPN from your home you should be able to read the recomended chapter 4.
Green third assignment
It seems the current trend is all for recycling and reducing the waste we create. I am joining this effort now by presenting you a fully recycled third assignment about IP fragmentation.
Please note that the due date is wrong (recycling sometimes has some problems). The correct due date is April 6th.
Please note that the due date is wrong (recycling sometimes has some problems). The correct due date is April 6th.
Solved 1st term exam
Already available, just follow this link.
Marks will be available in a few days in this same site as an update of this post.
Update: Exam marks are available in the same link as the attendance pages. Please note that solved exam contained a couple of errors that have been now fixed, just download a fresh version.
Second Update: It seems that some of you have trouble doing the math to know your current score, so now you have that numbers on the mark's page. I repeat what I explained the first day of class and it is detailed in Chapter0 slides.
The same logic will be applied to the second term marking and then, both marks will be averaged to obtain your final grade.
Please remember the pass mark is 50%, so if you score less than this you will have to work harder on the second term to pass the subject.
Lab exam is still being marked so it has not yet been accounted for.
Third Update: Now the lab mark has been included. Go and check yours!
Marks will be available in a few days in this same site as an update of this post.
Update: Exam marks are available in the same link as the attendance pages. Please note that solved exam contained a couple of errors that have been now fixed, just download a fresh version.
Second Update: It seems that some of you have trouble doing the math to know your current score, so now you have that numbers on the mark's page. I repeat what I explained the first day of class and it is detailed in Chapter0 slides.
mark(%) = attendance*10/classes + (9-assignments)*exam/10 + assignments*10 + labThe underlying logic is that exam only accounts for 70% of the final mark if you pass two assignments, 80% if you pass one assignment or 90% if you did not pass (or did not turn in) any assignment. Also note that failing on an assignment has not any negative effect on your score.
The same logic will be applied to the second term marking and then, both marks will be averaged to obtain your final grade.
Please remember the pass mark is 50%, so if you score less than this you will have to work harder on the second term to pass the subject.
Lab exam is still being marked so it has not yet been accounted for.
Third Update: Now the lab mark has been included. Go and check yours!
1st term exam
To be held January 30th, classroom B-5 at 10:00am laboratory exam.
For those of you who missed one or more laboratory sessions the exam will start at 10:30am. Duration two and a half hours.
For those of you who missed one or more laboratory sessions the exam will start at 10:30am. Duration two and a half hours.
Second assignment solution
It might not be the cleanest approach but I try to keep the line count low. You may download this server code that performs as required on the assignment#2 text.
What you may find weird is the fact that a timeout message is printed every 10 seconds when an upload is not taking place (therefore block number is zero). If you do not like this you can add an "if" sentence not to print that unless block number is larger than zero, but for me it serves as a sign that the server is up and running even when a file is not being received.
Second assignment marks
Ramazan, Anna, Manuel, Javier and Edgar have turned assignment#2 in. All of them have passed, though there are some comments, read on.
Some of them had the creative idea that a timeout event can stop the server. Let me tell you that "the show must go on" whatever it happens to the server. So you need to treat (catch) any exception that might cause the server to stop working.
On the other hand, I asked explicitly for the received files to be named in a certain way. Again some of you did not follow this part of the specification.
Edgar made the important observation that the performance when transmitting with this system is quite poor. And he also pointed out the cause: The use of a stop and wait protocol where the round trip time compared with the transmission time is quite significant.
Finally, to all of you that for any reason did not send me your work I want to encourage you to do it next time. I really think that assignment work can help you to improve your practical knowledge of network programming. Think of it like a little challenge and try not to follow the advice on this page.
Some of them had the creative idea that a timeout event can stop the server. Let me tell you that "the show must go on" whatever it happens to the server. So you need to treat (catch) any exception that might cause the server to stop working.
On the other hand, I asked explicitly for the received files to be named in a certain way. Again some of you did not follow this part of the specification.
Edgar made the important observation that the performance when transmitting with this system is quite poor. And he also pointed out the cause: The use of a stop and wait protocol where the round trip time compared with the transmission time is quite significant.
Finally, to all of you that for any reason did not send me your work I want to encourage you to do it next time. I really think that assignment work can help you to improve your practical knowledge of network programming. Think of it like a little challenge and try not to follow the advice on this page.
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