LBSC 690 Section 0201 and 0301 Final Exam Friday, December 13, 1996 Instructions: The maximum possible score on this exam is 100 and the minimum possible score is -3. There are six questions. The number of points available for each question is clearly indicated at the beginning of the question, as is the breakdown of points for each part of the question. Please pay attention to the number of points for each part. Some parts are worth so few points that they may not be worth your time to work on them! You may use your own personal copy of Blissmer and any notes that you have handwritten in your copy of Blissmer, and you may use a calculator. You may not use any other material. Please put all of your answers in the exam booklet that has been provided. You may answer the questions in any order. Only answers written in your exam booklet will be graded. Please also turn in this exam by placing it inside your exam booklet. It is a violation of academic integrity to reveal any information about this exam to any LBSC 690 student that has not yet taken it. Section 0301 will not take their final exam until Wednesday, December 18 at 5:30 P.M. ---------------------------------------------------------------------- 1. (20 points) Following the lead of the CLIS OWL lab, Santa is planning to replace all of his computers with Pentiums. He found the following advertisement in the Monday Washington Post Business section, but he needs a little help figuring it out. So he scanned it in and sent it to you by email: SYSTEM CONFIGURATION Intel Triton III VX Chipset PnP BIOS 256k Pipeline Cache 16 MB EDO RAM 60 ns PCI 2 MB Video Card with Mpeg 8X CD-ROM Soundblaster 16 PnP 1.6 GB Hard Drive 33.6 Fax Modem 60 Watt Speakers 104 Windows 96 Compatible Keyboard Microsoft Comaptible Mouse Microsoft Windows 95 with Manual Santa wants to know the answers to the following questions: a) (5 points) What the heck is "16 MB EDO RAM 60ns" used for? b) (5 points) Santa was told by his network manager that that component would be too slow. What speed RAM would Santa need if he wanted to connect it directly to a 100 MHz Pentium (assuming 1 operation per hertz, so that's really 100 megaflops)? c) (5 points) Mrs. Claus, a recent graduate of LBSC 690, mentioned that one of the components in the advertisement would make faster RAM unnecessary. Which component is that? d) (5 points) Mail delivery to the North Pole has been deteriorating rapidly, so Santa is planning to switch over to electronic gift lists. Approximately how many pages of gift lists will Santa be able to store on the "1.6 GB Hard Drive" that comes with each computer? Show your work. e) (0 points) Assuming that Santa assigns 40 elves to work for 60 hours each week, how long will it take to make each list and check it twice? You are reminded to check the number of points for each question before answering. This is your last warning. 2. (20 points) One thing Santa wants to do with the new computers is create a database that contains information from all of the toy catalogs he receives. He has offered you extra presents this year if you will design the tables for him. Here's what he wants to record: Toy name (30 characters) Toy price (numeric) Manufacturer name (30 characters) Manufacturer's address (100 characters) (100 characters) Manufacturer's country (20 characters) Mrs. Claus also mentioned to Santa that he would need some extra things in the tables. He can't remember for sure, but they were either called "locks" or "keys". a) (10 points) Design two tables that together can be used to print the information necessary to order any toy. b) (10 points) Santa's budget has been undergoing a downsizing this year, but he still needs to operate within the constraints imposed by the World Trade Organization agreement on geographic distribution of the toy manufacturing base. Design a query that will print ONLY the name of every toy costing less than $25 that is produced in Djibouti, a country in Africa. 3. (15 points) Santa is considering moving to Florida and continuing to manage his enterprises at the North Pole from there. Unfortunately, Florida is in the Eastern time zone, and the North Pole is in EVERY time zone! Santa has decided that he would need an "asynchronous remote" Computer Supported Cooperative Work (CSCW) system in order to ensure that he could get his important work done without being up at all hours of the night. a) (4 points) Give two examples of asynchronous remote CSCW that Santa might find useful. b) (5 points) Santa is also considering using this same technology to conduct the monthly training sessions for his elves. In discussions with Mrs. Claus he discovered that he has a pedagogic rationale for using computers in this way. What's that? c) (6 points) Mrs. Claus believes that "Silicon Snake Oil," a book by Clifford Stoll, would make a good Christmas gift because books are stable. She said that she got that term from an article about how various media are used in education that was written by a fellow named Kozma. Santa doesn't do much reading, but he once saw a video of a talk by Clifford Stoll. He thinks that it would be hard to characterize anything that Clifford Stoll was involved in as "stable." What is Mrs. Claus talking about? 4. (20 points) After checking on real estate using the world wide web and learning that house prices are higher in Florida than at the North Pole, Santa decided to remain where he was. So instead of buying the CSCW system he had been considering, he went ahead and bought the Pentiums that he had seen advertised. Believing that the Internet is the way of the future, Santa set up an Intranet at the North Pole. a) (5 points) Shortly after being installed, all of Santa's new computers got the new "Grinch" virus. Santa's computers all came with virus checking software, though. How come it didn't detect the Grinch virus? b) (+3 if right, -1 if wrong) Almost immediately after getting the Grinch virus off of all of his machines, Santa's network was disrupted by a group of evil graduate students at the University of Alaska who repeatedly downloaded the same web page from http://www.northpole.net/toys.html 15 trillion times every hour. This is known as: A) a trojan horse B) a denial of service attack C) spoofing D) security through obscurity c) (+3 if right, -1 if wrong) In order to prevent this sort of problem in the future, Santa installed a: A) firewall B) virus checker C) second web server D) digital signature d) (9 points) Before that solution could be implemented, someone used a password cracker to discover Santa's password. This evil person then used Santa's account to send email to every kid in the world announcing that Christmas had been cancelled! It took a team of 3,726 elves 42 days to write personal letters to every kid on the Internet explaining that Christmas had not really been cancelled and that it was important that they continue to be good because Santa did in fact know whether they had been naughty or nice and if they were nice they would get lots of presents at Christmas. Santa discussed this problem with Mrs. Claus and she explained that in LBSC 690 she had learned some ways of selecting and using passwords that could reduce the likelihood of this sort of problem. Name three good rules of thumb that together would result in effective protection of Santa's account. 5) (25 points) In addition to computerizing his workshop, Santa also wants to automate the North Pole library. As you might expect, this is a special library with some unique collections on toy history, toy manufacturing, and toy marketing. It also has a large section on Saints, although a certain Saint Nicholas seems to receive most of the attention. There's also the usual material on animal husbandry that is found in any facility in which reindeer are responsible for a substantial portion of the capital investment and operating expenses. a) (15 points) Santa has asked his librarian to explain to him how information generated by one library function would be used by the other library functions in this new system. Mrs. Claus suggested that a diagram of the sort she saw in LBSC 690 might provide some insight. Santa's librarian has contacted you in the hopes that you might be able to help. The library's new system will include an Online Public Access Catalog (OPAC), a circulation control system, and facilities for cataloging and inter-library loan. Overdue notices are handled by the circulation system, and there are no fines. Because the acquisition budget is so small, acquisition and collection policy will be handled manually. Produce a diagram of the information flow that identifies what sort of information flows between each task and indicates the direction of the flow (include both the manual and the automated tasks). b) (+3 if right, -1 if wrong) Santa's librarian needs this diagram quickly, but you don't have a fax number handy for the North Pole. You decide to scan the diagram and attach the image file to an email. What format should you use for the scanned image file? A) JPEG B) GIF C) HTML D) MPEG c) (7 points) You need to find the zip code for North Pole, Alaska so that you can send your bill to Santa's librarian. After searching Alta Vista for "zip code" and getting 500,000 hits (top 20 shown) you decide that it would be easier to use a service that categorizes information on the Web than to use a search engine. What service would you use and how would you use it? (BTW, North Pole, Alaska really exists and the zip code is 99705). 6) (0 points) Write a Java program to verify the following computation: No known species of reindeer can fly. But there are 300,000 species of living organisms yet to be classified, and while most of these are insects and germs, this does not completely rule out flying reindeer which only Santa has ever seen. There are 2 billion children in the world (persons under 18). But since Santa doesn't (appear to) handle Muslim, Hindu, Jewish, or Buddhist children, that reduces the workload by 85% of the total - leaving 378 million according to the Population Reference Bureau. At an average (census) rate of 3.5 children per household, that's 91.8 million homes. One presumes there is at least one good child per house. Santa has 31 hours of Christmas to work with, thanks to the different time zones and the rotation of the earth, assuming he travels east to west (which seems logical). This works out to 822.6 visits per second. This is to say that for each Christian household with good children, Santa has 1/1000th of a second to park, hop out of the sleigh, jump down the chimney, fill the stocking, distribute the remaining presents under the tree, eat whatever snacks have been left, get back up the chimney, get back into the sleigh and move on to the next house. Assuming that each of these 91.8 million stops are evenly distributed around the earth which, of course, we know to be false but for the purposes of our calculations we will accept), we are now talking about .78 miles per household, a total trip of 75.5 million miles, not counting stops to do what most of us do at least once every 31 hours, plus feeding, etc. That means that Santa's sleigh is moving at 650 miles per second, 3000 times the speed of sound. For purposes of comparison, the fastest man-made vehicle, the Ulysses space probe, moves at a poky 27.4 miles per second - a conventional reindeer can run, at tops 15 miles per hour. The payload on the sleigh adds another interesting element. Assuming each child gets nothing more then a medium sized lego set (2 pounds), the sleigh is carrying 321,300 tons, not counting Santa, who is invariably described as overweight. On land, conventional reindeer can pull no more than 300 pounds. Even granting the 'flying reindeer' can pull TEN TIMES that normal amount, we cannot do the job with eight, or even nine, we need 214,200 reindeer. This increased the payload - not even counting the weight of the sleigh - to 353,430 tons. Again for comparison - this is four times the weight of the Queen Elizabeth 353,000 tons traveling at 650 miles per second creates enormous air resistance. This will heat the reindeer up in the same fashion as spacecraft re-entering the earth's atmosphere. The lead pair will absorb 14.3 quintillion joules of energy per second. Each. In short, they will burst into flames almost instantaneously, exposing the reindeer behind them, and creating a deafening sonic boom in their wake. The entire reindeer team will be vaporized within 4.26 thousandths of a second. Santa meanwhile, will be subject to centrifugal forces 17,500.06 times greater than gravity. A 250 pound Santa (which seems ludicrously slim) would be pinned to the back of the sleigh by a 4,315,015 pounds force. Points or no points - have a happy holiday season and try to stay away from overzealous engineers :-)