tag:blogger.com,1999:blog-85910212977295271242024-03-05T14:19:13.993+08:00MIS AlleyDigital Scribbles in a Digital WorldPatrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.comBlogger24125tag:blogger.com,1999:blog-8591021297729527124.post-32506349862614565882009-12-01T01:00:00.004+08:002009-12-01T01:25:35.647+08:00For the Nth TimeI created this blog to serve as a repository for my MIS-related stuff from UPOU. Back then, my intent was to keep updating this as often as I can. My purpose was a blend of it to be a time-capsule of sort and to be of aid to others who would wish to pursue the post-grad degree themselves.<div><br /></div><div>Being one comfortable with blogging, I thought I could actually live up to that. What I never anticipated was that real life would have its way with the blogger from time to time.</div><div><br /></div><div>So the hiatus was mainly about:</div><div><ul><li><b>Work</b>. Of course this trumps almost everything in the list and with the way deadlines and expectations pile up, this time of the year, it shouldn't be surprising if I end up silent here again.</li><li><b>School</b>. While this is mostly about school, the IS238-IS272 combo the previous sem, actually bore down on most of my free time. So much that the weeks actually felt like I had coffee for blood in my veins. Add to that taking the program's comprehensive exam, (of which I will write about soon), and that pretty much pictures how hectic school was. </li><li><b>Family</b>. While the family ranks among the top of my priorities, affairs tend to become more demanding as the family ends up becoming bigger. My brother, for instance, had <a href="http://patrickestrella.wordpress.com/2009/11/30/tying-the-knot/">his wedding last Saturday</a>. </li><li><b>Health</b>. Given hectic schedules and busy routines, (not to mention <a href="http://patrickestrella.wordpress.com/2009/10/02/the-long-walk-home-1-of-3/">a crazy typhoon experience</a>,) it's always easy to neglect one of rest and a healthy lifestyle. So it wasn't really surprising that around the middle of the month, I had to be treated for something before I get down with full-blown pneumonia or tuberculosis. I'm alright now and I'm on my way to getting rid of the cancer stick from my routine forever. </li></ul>I hope to be able to write again here soon before I ride off into the sunset though.</div><div><br /></div>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-45122172324583745602009-06-25T23:48:00.002+08:002009-06-25T23:52:49.400+08:00IS238 - Quiz 1Yup. I'm done... and relieved...<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhc8V8WnjNTmEsz_hyx0isWhywJfZj7W0IuqX24RSyhaDT_BndFGsQB2xgJLe9S0Tr61-EBhdIPc2q2-A_mARwZI8QbENAczttmvW_9evta5EKM9MASvbc191TGy6a4kqmWq15fHtlrXGek/s1600-h/Server+Screenshot.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px; height: 224px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhc8V8WnjNTmEsz_hyx0isWhywJfZj7W0IuqX24RSyhaDT_BndFGsQB2xgJLe9S0Tr61-EBhdIPc2q2-A_mARwZI8QbENAczttmvW_9evta5EKM9MASvbc191TGy6a4kqmWq15fHtlrXGek/s320/Server+Screenshot.png" alt="" id="BLOGGER_PHOTO_ID_5351293230992883426" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEha6PH0hXYJjlwQCqC33IdZsQjd9jLEYTbfwEwPZGSZLY0AO7BwHP1wqZMLXaevHcoOZcrwewE9AgnTjjb6vEXKbL0p7H_wS7yDoNMqs57sfKpKXV2aVvSG4XL8pGtJ79QssqpByMq2Q-9x/s1600-h/Client+Screenshot.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px; height: 224px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEha6PH0hXYJjlwQCqC33IdZsQjd9jLEYTbfwEwPZGSZLY0AO7BwHP1wqZMLXaevHcoOZcrwewE9AgnTjjb6vEXKbL0p7H_wS7yDoNMqs57sfKpKXV2aVvSG4XL8pGtJ79QssqpByMq2Q-9x/s320/Client+Screenshot.png" alt="" id="BLOGGER_PHOTO_ID_5351293231641092722" border="0" /></a><br />For now that is.Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-80706068044714113272009-06-21T00:07:00.002+08:002009-06-21T00:12:15.465+08:00Over OCRI've never given a thought on OCR stuff much before because I never thought of a situation I would end up actually needing it.<br /><br />Just early this day, I actually needed to find a solution towards that direction.<br /><br />More specifically, I have a PDF in IS238 with lengthy code in it and I need to have both server and client codes running. While the intuitive step of having the program files is to copy and paste everything, it turned out that things won't be easy as that. It turned out that the text turned out garbled when pasted in <a title="Notepad++ Website" href="http://notepad-plus.sourceforge.net/" target="_blank">Notepad++</a>.<br /><br />As a <a title="PDF Encryption" href="http://misalley.blogspot.com/2007/11/pdf-encryption.html" target="_blank">previous endeavor</a> has shown, my tinkering inclination actually had me try to have the garbage figured out--how values map to the other. After a while I gave up though. I thought I should have ended up typing the 6 page mammoth instead of ending up having to spend an entire day decyphering the thing.<br /><br />The only thing left for me to try was the OCR solution. Not wanting to have additional software installed though, I spent a few clicks at Google and found <a title=" How to OCR images and printed documents using Office 2007 on Vista" href="http://vista.blorge.com/2007/07/29/how-to-ocr-images-and-printed-documents-using-office-2007-on-vista/" target="_blank">a surprising solution</a>. Surprising in the sense that I never thought I'd find something of actual use for MS Office's OneNote, its <strong>Copy Text from Picture</strong> functionality was literally a lifesaver here.<br /><br /><div style="text-align: center;"><img class="size-full wp-image-270" title="OneNote OCR" src="http://patrickestrella.wordpress.com/files/2009/06/onenote1.jpg" alt="OneNote's Copy Text from Image" width="468" height="282" /><br /><span style="font-weight: bold;">OneNote's Copy Text from Picture</span><br /></div><br />So after a few clicks on Adobe Reader's Snapshot tool before getting the text from OneNote, I got what my codes. Well, sort of since there were a few glitches in the translation that I had to correct still.<br /><br />I'll happily take that over straining these fingers having to retype everything though.Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-54567315829703062282008-07-14T00:37:00.004+08:002008-07-14T01:06:16.773+08:00Forum SnapshotsThe last time I posted about something here about the computing ethics subject I'm currently taking up, it had that tone of a dilemma about whether to post my experience being active at <a href="http://www.highfiber.org/">highfiber</a>. It was due primarily to the fact that the place is pretty much an asylum sans the downright retardedness back in the time I choose to associated my activeness with the site.<br /><br />It goes without saying then that to write of the experience in a relatively more formal online venue would be to advertise myself short of being an alpha male online. At least that was how I saw it.<br /><br />And it didn't help me either to go on and on revising my supposed post. What had me eventually post my piece on the forum personality question was the professor's reaction towards my comment on the <a href="http://www.matrixmediaphilippines.com/upou/index.php?topic=156.0">ethics of killing because of self-defense</a>.<br /><br />To make the long story short, the professor misunderstood what I said. I can't say I blame him though because of the way I chose to shorten my comment. The venue was definitely more formal than what I'm used to at highfiber hence the need to be more on the look out for what I leave around there.<br /><br />So I answered back essentially to clarify myself. Apparently there was no harm intended from our mentor really. In choosing to answer back the way I did however, it suddenly struck me that I already showed a glimpse of my arrogance, and philosopher and grammarian tendencies. In doing so, I found it much easier to finalize the revisions to my piece and go ahead with posting what I had in mind for the question.<br /><br />Who says flame wars always end up ugly? :DPatrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-63333473438252369992008-07-14T00:07:00.003+08:002008-07-14T00:33:10.939+08:00Wading through Ada Programming<div style="text-align: justify;"><span style="font-size:85%;"><span style="font-family: verdana;">I got to "experience" programming in Ada back at college first. Back then, I remember having used a certain version of GNAT. It was for Win95 if I remember it right.</span></span><br /><br /><span style="font-size:85%;"><span style="font-family: verdana;">Now, I tried to get the same environment for my notebook to help me answer an FMA question. Never did I realize that it would be that hard. I spent more than 6 hours to get the <a href="http://libre.adacore.com/gps">GNAT Programming Studio</a> (GPS) IDE going for me but eventually, I had to raise up my arms in surrender in the end. Getting my ADB file, (a simple </span><span style="font-weight: bold; font-family: verdana;">Hello World</span><span style="font-family: verdana;"> program for crying out loud,) to work in the IDE consumed a lot of my time as the compiler and build messages were too cryptic. The scarcity of related material from the internet helped me reach the conclusion that were I to get the stuff going, it would only be because I had already sacrificed time I should be spending for other important stuff too.</span></span><br /><br /><span style="font-size:85%;"><span style="font-family: verdana;">Thanks to this </span><a style="font-family: verdana;" href="http://sandbox.mc.edu/%7Ebennet/ada/index.html">Mississippi College resource</a><span style="font-family: verdana;">, I was able to get some stuff going through the command line. It was not as pretty but it got what I wanted done: to test some named compatibility scenarios in Ada. The essence was particularly in the </span><a style="font-family: verdana;" href="http://sandbox.mc.edu/%7Ebennet/ada/gnat_ug/gnat_ug.html">GNAT (compiler) User's Guide</a><span style="font-family: verdana;"> page.</span></span><br /><br /><span style="font-size:85%;"><span style="font-family: verdana;">In particular, the following lines of code could be used to generate the executable given a <span style="font-weight: bold;">hello.adb </span>file:</span></span><br /><br /><span style="font-size:85%;"><span style="font-family: courier new;">gnatgcc -c hello.adb</span></span><br /><span style="font-size:85%;"><span style="font-family: courier new;">gnatbind hello</span></span><br /><span style="font-size:85%;"><span style="font-family: courier new;">gnatlink hello</span></span><br /><br /><span style="font-size:85%;"><span style="font-family: verdana;">or simply:</span></span><br /><br /><span style="font-size:85%;"><span style="font-family: courier new;">gnatmake hello.adb</span></span><br /><br /><span style="font-size:85%;"><span style="font-family: verdana;">Thanks to <a href="http://sandbox.mc.edu/%7Ebennet/index.html">Dr. Bennet</a> for the helpful information.</span></span><br /></div>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-70585272038204877542008-06-23T21:41:00.011+08:002008-06-23T22:53:41.967+08:00Prelude to a Few Forum Snapshots<p class="MsoNormal" style="margin-bottom: 12pt; text-align: justify;"><span style=";font-family:Verdana;font-size:85%;" >Since last week, I've had my answer to the activity for module 6 where the student's forum behavior is asked of. Here's a snippet for the instructions for the exercise for the module in particular:</span><span style=";font-family:Verdana;font-size:85%;" ><br /></span></p><blockquote><p class="MsoNormal" style="margin-bottom: 12pt; text-align: justify;"><span style=";font-family:Verdana;font-size:85%;" >...Our activity would be to go over the various types of "<a href="http://redwing.hutman.net/%7Emreed/" target="_blank">Flame Warriors</a>"by <a href="http://redwing.hutman.net/%7Emreed/warriorshtm/announcement.htm" target="_blank">Mark Reed</a> and find out which of the types you identify with (there are more than 80 types, so no denial queen/king here) and also maybe those whom you often meet in your online encounters.</span><span style=";font-family:Verdana;font-size:85%;" ><o:p></o:p></span><span style=";font-family:Verdana;font-size:85%;" ><br /></span></p><p class="MsoNormal" style="margin-bottom: 12pt; text-align: justify;"><span style=";font-family:Verdana;font-size:85%;" >Then write a post about it (a kind of short essay- try to think out of the box) - about yourself and about others. Try to comment to at least 1 post that your classmate would make (to encourage, to clarify, to console, or to empathize.)</span></p></blockquote><p class="MsoNormal" style="margin-bottom: 12pt; text-align: justify;"><span style=";font-family:Verdana;font-size:85%;" ></span><span style=";font-family:Verdana;font-size:85%;" ><o:p></o:p></span><span style=";font-family:Verdana;font-size:85%;" >It wasn't easy to come up with content as I've registered a lot of "hits" in that checklist in describing myself and other people I've interacted with at <a href="http://highfiber.org/">highfiber</a>. Hell, I didn't even bother writing each categorization despite the fact that I've picked up at least 20 personas easily!<o:p></o:p><br /></span></p><p class="MsoNormal" style="margin-bottom: 12pt; text-align: justify;"><span style=";font-family:Verdana;font-size:85%;" >I'm unsure though as to how my classmates there would take the personas to which I qualify. The decorum on our online forum at <a href="http://www.upou.org/">upou</a> is generally formal and accomodating while hifi, to which I associate myself with for more than 5 years now, is more on the "alternative" side of online interaction. By alternative, I'm referring to how the community started as a sanctuary for people who have had enough of poseur-stuff at friendster and PEX--enormous blinking texts, attention-whoring animated GIFs, etc.</span><span style=";font-family:Verdana;font-size:85%;" ><o:p></o:p></span><span style=";font-family:Verdana;font-size:85%;" ><br /></span></p><p class="MsoNormal" style="margin-bottom: 12pt; text-align: justify;"><span style=";font-family:Verdana;font-size:85%;" >What struck me when I first had my way around the site was how unpretentious the people were in talking about stuff in such a way that it ended up worth finding time to actually read content there. And stuff there's literally anything under the sun: politics, current events, global warming, education, religion, economics, dating, kids, etc.</span><span style=";font-family:Verdana;font-size:85%;" ><o:p></o:p></span><span style=";font-family:Verdana;font-size:85%;" ><br /></span></p><p class="MsoNormal" style="margin-bottom: 12pt; text-align: justify;"><span style=";font-family:Verdana;font-size:85%;" >People there refer to the place as an asylum and one of the many reasons why is that flamewars often erupt there. Unlike other forums though, people there actually have accepted the fact as a way of life, as something imminent because of the diversity of people there and the amorphousness of the community itself. I've been to a lot of other more orderly forums but I just can't find myself writing about any other forum apart from hifi.</span><span style=";font-family:Verdana;font-size:85%;" ><o:p></o:p></span><span style=";font-family:Verdana;font-size:85%;" ><br /></span></p><p class="MsoNormal" style="margin-bottom: 12pt; text-align: justify;"><span style=";font-family:Verdana;font-size:85%;" >So I'm actually thinking hard over my supposed post over the last few days. No matter how I tone down what I wrote, it still ends up meaning something I'm too hesitant to post especially if it's to be read by "normal" people. :))</span><span style=";font-family:Verdana;font-size:85%;" ><o:p></o:p></span></p>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-40033639597847367232008-06-16T22:41:00.003+08:002008-06-16T23:29:37.531+08:00Why Searching Has Become a Skill<div style="text-align: justify;">Since the ethics portfolio is to appear a journal as much as possible, I've decided to "litter' this with my little thoughts on related stuff. Seemingly-related ones included.<br /><br />Sir GGR's piece on how to answer the forums got my attention the other day. That is when he said:<br /><br /><blockquote>Just one thing to remember though..., the challenge for all is <span style="font-weight: bold;">personal critical thinking</span> and <span style="font-weight: bold;">personal reflection</span>. Don't just accept what people have written but rather process them and be brave to post your own insights (backed by evidences of course).<br /><br />This is what we lack in this technology and information-rich society. Let's face it, many in today's world can't process quality of information rather they get lost or drowned in the superficial ones.</blockquote><br />How true.<br /><br />How else would you explain the difficulty of getting decent material from searches these days? Sure there are some gems you'll get to stumble along the way but that still doesn't account for the rest of the senseless ones you'll have to wade through to get to the good stuff. And by good stuff I mean those that actually qualify as valid sources from the subject.<br /><br />It is quite rare when you'd find someone who actually spends time writing substantial thoughts on his/her own. Personally I find it so much an eyesore to wade through too much post-modern delivery of entries in a particular blog.<br /><br />Try and make a real paper acceptable to strict academic standards and you'll get what I mean. Sure <a href="http://en.wikipedia.org/">wikipedia</a> gets you off to a good start but there's still a lot of work to be done.<br /><br />That and the popularity of readers to get content perceived to be worth one's time are telltale in themselves. While the issue of convenience to get information the fastest way seems to be the reason for the popularity of the latter, it also brings to fore another reason: time spent for searching for sensible content is better spent for something more productive.<br /><br />Finally we see SEO as another buzzword in growing usage around cyberspace. With the battle of the search rankings raging on for the past few years because of the Web 2.0 movement, it really isn't hard to see how the quality of content has to eventually give way to its quantity.<br /><br />And to think that once I was raring to post <a href="http://www.herecomeseverybody.org/2008/04/looking-for-the-mouse.html">this interesting piece</a> on what the author calls "social surplus" somewhere. Perhaps Luis hit something there when writing about <a href="http://guttervomit.com/2008/05/05/zero-barrier/">his piece</a> about "blogs and their rather sordid relationship with mainstream media:"<br /><br /><blockquote>The point I’m trying to make is this: I do not begrudge anyone their grammatically-challenged, horribly-written detailing-my-last-shampoo-purchase train-wreck-of-a-blog. This is your God-given right as someone who (probably) pays for Internet access. However, we shouldn’t sell it like it’s the cure for cancer either. We need to accept the fact that the Internet - particularly the part of it that’s user-generated - is full of crap. It’s filled to the brim and everyday the container overflows and splashes everyone in the face with crap. And we shouldn’t wonder why people on the other side of the fence look at us and shake their heads, saying, “Wow, look at those people doing backflips into that giant pool of feces.”<br /></blockquote><br />Right.<br /></div>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-74936892850849255282008-06-03T21:08:00.005+08:002008-06-03T21:54:13.366+08:00A Second Serving<span style="font-size:85%;">So after the summer's through (or at least it's supposed to be as we're still waiting for the rain from where I am,) I'm back in school. I had enrolled in IS201 and IS214 last April then had gotten the course materials from the learning center last weekend already. While I have yet to get my grade for 2 of the 3 subjects I took up last semester, I have to start with the real thing now.<br /><br />IS201 is on Computer Ethics while IS214 is on Programming Languages. The two subjects are actually similar to some major subjects I took when I was still an undergrad at UP Diliman. Those would be CS207 (Special Topics) and CS150 (Programming Languages.) While intuitively that should work to my advantage, I'm not letting my guard down. Not when I got to take a look at the course requirements.<br /><br />Requirements for IS214 are much like IS215: 20% on FMAs and 80% on a make-or-break multiple choice final exams. While I'm giving myself a heads up on the IS215 serving of that examination, I know I could've done better. That's why I'm preparing for the exam a lot earlier this time.<br /><br />As for the IS201, I think they're a lot like the requirements in ENRM221: participation in online discussions, a submitted paper which in this case is called an Ethics Portfolio and a final exams. While the Ethics Portfolio is not that formal, it has to be written gradually so as to present something substantially noteworthy. Hence a lot of the meat I'll be including there will appear here just as gradually. Since I was dissatisfied with how my ENRM221 concept paper I wrote for a number of weeks came out, I'm putting in more time to come up with something which will end up something satisfactory.<br /><br />Now if only I can organize everything I have in mind.<br /></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-17107313849445661662008-03-02T20:37:00.003+08:002008-03-02T21:11:36.361+08:00ENRM 221 Finals<span style="font-size:85%;"><span style="font-family:verdana;">The elective I took up this semester is a subject on the socio-cultural perspectives on the environment. A course requirement for the subject would be a final examination so in the same vein as in the previous post, I'm posting the </span><a style="font-family: verdana;" href="http://www.freewebs.com/patrickestrella/ENRM221/Exam%20Reviewer.doc">exam reviewer</a><span style="font-family:verdana;"> I used.</span><br /><br /><span style="font-family:verdana;">Again, apologies for typos in the answers to the guide questions.</span><br /></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-28117992938119323862008-03-02T18:14:00.003+08:002008-03-02T18:38:26.228+08:00IS215 - Finals<div style="text-align: justify;"><span style="font-family: verdana;font-size:85%;" >To anyone who'll be taking IS 215 in the future and fortunate enough to find this post will eventually have to face the final examinations. So I'm leaving the two-part reviewer I made for myself which turned out to be helpful after all.<a href="http://www.freewebs.com/patrickestrella/IS215/Exam%20Reviewer.doc"> The first part</a> covers the <span style="font-weight: bold;">Single Processors</span> topic while <a href="http://www.freewebs.com/patrickestrella/IS215/Exam%20Reviewer2.doc">the second</a> spans the topics on <span style="font-weight: bold;">Networks</span> up to the <span style="font-weight: bold;">Internet</span>.<br /><br /></span><span style="font-family: verdana;font-size:85%;" >Pardon me for the occasional typo errors though. I had been so much in a hurry that correcting those stuff went beyond me already. Also the Parallel Systems and the Internet can still be made more comprehensive. Blame it all on the rush again. :D</span><br /></div>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-30168270500570504092008-03-02T16:40:00.012+08:002008-03-02T18:08:59.470+08:00IS 226 - Project 1 - Part 2<div style="text-align: justify;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgLo9YN5y414LxCEVSmg_H_E6b5pwFu9YfluU4g8H_Vi_1u_L8wtxslsyjEjY9IeDxift393vjd4FvYuhUKKAULn48_xMoUy4uezfd8ckxrlF63339VsrF_RPoNmAF_4lbGwfRYJmnq-kS/s1600-h/1.png"><img style="margin: 0pt 0pt 10px 10px; float: right; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgLo9YN5y414LxCEVSmg_H_E6b5pwFu9YfluU4g8H_Vi_1u_L8wtxslsyjEjY9IeDxift393vjd4FvYuhUKKAULn48_xMoUy4uezfd8ckxrlF63339VsrF_RPoNmAF_4lbGwfRYJmnq-kS/s320/1.png" alt="" id="BLOGGER_PHOTO_ID_5173071224776844610" border="0" /></a><span style=";font-family:verdana;font-size:85%;" >And for Projects 2 and 3 anyway...</span><br /><br /><span style="font-size:85%;"><span style="font-family:verdana;">It was just a shame my first sem at school again after more than half a decade took away the little time I could afford to update this blog. Anyway I'm adding this link to the product of my full attention set at web development. And by web development I mean everything from web design to web technology codes.</span></span><br /></div><div style="text-align: justify;font-family:verdana;"><span style="font-size:85%;"><br />Which is the reason why I chose to include projects 2 and 3. The next projects are essentially refinements to the preschool home page requirement for the first project so it definitely makes sense to lump them all here together.<br /><br /></span><span style="font-size:85%;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilajZTBcK_f8p3RHzvK52SWIZm7arvSj-okzZugyBH7kTAMrdiKfd3K38sSGXvoqCDfYSdo89NnEFruoPy1SS9ALKbCbeb9te9GCMdQXibHk3tNwQ-D4tgKAuwJCTGmqYj0K97FdCBuW_X/s1600-h/2.png"><img style="margin: 0pt 0pt 10px 10px; float: right; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilajZTBcK_f8p3RHzvK52SWIZm7arvSj-okzZugyBH7kTAMrdiKfd3K38sSGXvoqCDfYSdo89NnEFruoPy1SS9ALKbCbeb9te9GCMdQXibHk3tNwQ-D4tgKAuwJCTGmqYj0K97FdCBuW_X/s320/2.png" alt="" id="BLOGGER_PHOTO_ID_5173072831094613330" border="0" /></a></span><span style="font-size:85%;">Project 2 takes off from project 1 by requiring additional themes to the homepage output from the first. That is, project 2 requires additional CSS files so that a different look and feel would be provided for the user without any changes to the XHTML codes. Kind of reminds you of <a href="http://www.csszengarden.com/">CSS Zen Garden</a>. Finally there should be at least three additional themes apart from the default one coming from the first project.<br /><br /></span><span style="font-size:85%;">Project 3 on the other hand, required JavaScript codes to validate user inputs during login, depending on the type of user signing in. For the particular project, that would either be <span style="font-style: italic;">student</span>, <span style="font-style: italic;">teacher</span> or <span style="font-style: italic;">parent</span>. Though I wouldn't really implement such validation that way for a production website in real life, I had no trouble finding my way in JavaScript. Prior to this course I was more of a back-end programmer so much of what I actually got from it was more on the web design end. That is, I found project 2 of the course more time consuming though not essentially more difficult.<br /><br />Without further ado here's the <a href="http://www.freewebs.com/patrickestrella/IS226/project1/pestrella%5Fproject2.html">home page</a>. The 2nd (Kids' Play) and 3rd (Black and White) screenshots not shown in this post can be found <a href="http://www.freewebs.com/patrickestrella/IS226/3.png">here</a> and <a href="http://www.freewebs.com/patrickestrella/IS226/4.png">here</a> btw.<br /></span></div>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-88220472214986926312007-12-01T10:27:00.000+08:002007-12-01T11:40:11.797+08:00IS 226 - Project 1 - Part 1Since reality's been keeping me so busy elsewhere, I thought I'd stick these links for the first IS 226 project. I thought it would be easier and less time-consuming for me to write an entry and get here from time to time rather than to organize my bookmarks which is close to a hodgepodge of ideas in an anything-goes forum.<br /><br />Anyway here are the said links.<br /><ol><li><a href="http://www.google.com/">www.google.com</a> and search for <a href="http://www.google.com.ph/search?hl=tl&client=firefox-a&channel=s&rls=org.mozilla%3Aen-US%3Aofficial&hs=Cjx&q=%22homepage+design%22&btnG=Hanapin&meta=">“homepage design”</a></li><li><a href="http://www.useit.com/alertbox/20031110.html">The Ten Most Violated Homepage Design Guidelines</a></li><li><a href="http://www.useit.com/alertbox/20020512.html">Top Ten Guidelines for Homepage Usability</a></li><li><a href="http://www.useit.com/alertbox/20030210.html">Homepage Real Estate Allocation</a></li><li><a href="http://www.useit.com/alertbox/20050523.html">The Canonical Intranet Homepage</a></li><li><a href="http://www.useit.com/alertbox/designmistakes.html">Top Ten Web Design Mistakes of 2005</a></li><li><a href="http://www.webcredible.co.uk/userfriendlyresources/webusability/planusablewebsite.shtml">Planning a usable website: A threestep guide</a></li></ol>And now for the homepage...Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-11277256872851806232007-11-25T09:39:00.000+08:002007-11-25T09:52:35.116+08:00IS215 - Concurrent Processes Exercises - 2<span style="font-size:85%;"><span style="font-family: verdana;">11. Write a monitor solution to the readers and writers problem given in (8).</span><br /><br /><span style="font-family: verdana;">12. Outline a method of handling (detecting and recovering from) lost messages in a message passing system.</span><br /><br /><span style="font-family: verdana;">13. What issues are true for message passing implemented in distributed systems and that are not issues when message passing is implemented in single processor systems.</span><br /><br /><span style="font-family: verdana;">14. Trace the execution of the program for reading and writing to a buffer. Try to illustrate all possible executions of this program.</span><br /><br /><span style="font-family: verdana;">read()</span><br /><span style="font-family: verdana;">{</span><br /><span style="font-family: verdana;"> while (TRUE) {</span><br /><span style="font-family: verdana;"> read(&item)</span><br /><span style="font-family: verdana;"> /* wait for empty buffer */</span><br /><span style="font-family: verdana;"> RECEIVE(write@uplb,&m);</span><br /><span style="font-family: verdana;"> construct_message(&m,item);</span><br /><span style="font-family: verdana;"> SEND(write@uplb,&m);</span><br /><span style="font-family: verdana;"> }</span><br /><span style="font-family: verdana;">}</span><br /><br /><span style="font-family: verdana;">write()</span><br /><span style="font-family: verdana;">{</span><br /><span style="font-family: verdana;"> while (TRUE) {</span><br /><span style="font-family: verdana;"> RECEIVE(read@upd,&m);</span><br /><span style="font-family: verdana;"> extract_item(&m,&item);</span><br /><span style="font-family: verdana;"> write(item);</span><br /><span style="font-family: verdana;"> SEND(read@upd,&m);</span><br /><span style="font-family: verdana;"> }</span><br /><span style="font-family: verdana;">}</span><br /><br /><span style="font-family: verdana;">15. Compare and contrast the merits of semaphores over message passing and vice versa.</span><br /><br /><span style="font-family: verdana;">16. Show that semaphores, monitors and message passing solutions to the concurrency problem are equivalent.</span><br /><br /><span style="font-family: verdana;">17. Write a solution to the Dining Philosophers problem that contains </span><br /><br /><span style="font-family: verdana;">a) starvation problem</span><br /><span style="font-family: verdana;">b) mutual exclusion violated</span><br /><br /><span style="font-family: verdana;">18. Write a correct solution to the Dining Philosophers problem that is different from the one given in book.</span><br /><br /><span style="font-family: verdana;">19. Show the correctness of the following solution to the Dining Philosophers problem:</span><br /><br /><span style="font-family: verdana;">int fork[5];</span><br /><br /><span style="font-family: verdana;">philosopher(i)</span><br /><span style="font-family: verdana;">{</span><br /><span style="font-family: verdana;"> for( ; ; ) {</span><br /><span style="font-family: verdana;"> think;</span><br /><span style="font-family: verdana;"> while does not have both forks {</span><br /><span style="font-family: verdana;"> wait(fork[i]);</span><br /><span style="font-family: verdana;"> if (fork[(i+1) mod 5)] is free</span><br /><span style="font-family: verdana;"> wait(fork[(i+1) mod 5]);</span><br /><span style="font-family: verdana;"> else</span><br /><span style="font-family: verdana;"> signal(fork[i]);</span><br /><span style="font-family: verdana;"> }</span><br /><span style="font-family: verdana;"> eat;</span><br /><span style="font-family: verdana;"> signal(fork[i]);</span><br /><span style="font-family: verdana;"> signal(fork[(i+1) mod 5]);</span><br /><span style="font-family: verdana;"> }</span><br /><span style="font-family: verdana;">}</span><br /><br /><span style="font-family: verdana;">20. Two brothers are seated opposite each other on a table with a plate of Palabok and fork. The action of each brother consists of alternate periods of picking food and chewing. The action starts by taking control of the fork, if successful starts to pick the food, then put the fork back on the table and starts to chew. After this, the cycle is repeated. A possible solution to this problem is the following:</span><br /><br /><span style="font-family: verdana;">jollibee()</span><br /><span style="font-family: verdana;">{</span><br /><span style="font-family: verdana;"> /* execute in parallel */</span><br /><span style="font-family: verdana;"> brother(1) || brother(2);</span><br /><span style="font-family: verdana;">}</span><br /><br /><span style="font-family: verdana;">brother(i)</span><br /><span style="font-family: verdana;">{</span><br /><span style="font-family: verdana;"> while (TRUE) {</span><br /><span style="font-family: verdana;"> pick_fork();</span><br /><span style="font-family: verdana;"> pick_palabok();</span><br /><span style="font-family: verdana;"> put-Down_fork();</span><br /><span style="font-family: verdana;"> chew();</span><br /><span style="font-family: verdana;"> }</span><br /><span style="font-family: verdana;">}</span><br /><br /><span style="font-family: verdana;">a) What are the possible problems that will be encountered by this solution?</span><br /><span style="font-family: verdana;">b) When do the problems you identified occur? Give one instance for each problem.</span><br /><span style="font-family: verdana;">c) Improve the solution using semaphores.</span></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-85724377902844857592007-11-25T09:32:00.000+08:002007-11-25T09:35:24.580+08:00IS215 - Concurrent Processes Exercises - 1<span style="font-family: verdana;font-size:85%;" >1. Give two examples of competing processes in an actual system. Do the same for cooperating processes.<br /><br />2. Write a procedure (different from what was given in this book earlier) use_resource() illustrating the following mutual exclusion problems:<br /><br />a) starvation<br />b) mutual exclusion violated<br />c) deadlock<br /><br />3. What is a monitor as used for regulating concurrent access to shared resources? Give examples of problems that may be eliminated by the use of a monitor.<br /><br />4. Describe an approach to process synchronization. Illustrate your answer by outlining an algorithm for a cyclic buffering system; show how your algorithm works by considering the progress of a consumer and a producer processes as they advance through critical regions, get delayed on queues, etc.<br /><br />5. When, and why, do processes need to synchronize their activities. Describe an approach to process synchronization based upon semaphores. Show how these may be used to solve two typical synchronization problems.<br /><br />6. Illustrate or argue the correctness of the Dekker's algorithm? Do the same for the Paterson's algorithm and the engineering solution.<br /><br />7. In order for the engineering solution to execute correctly, the test&set() function must be executed in one CPU cycle. Why is this so? What happens if this is not executed in one CPU cycle?<br /><br />8. The readers and writers problem models access to a database. Consider a big database with many competing processes wishing to read and write into it. It is acceptable to have multiple processes reading the database at the same time, but if one process is writing, no other process may have access to the database, not even readers. Write a program employing semaphores that ensure correct execution of this.<br /><br />9. What does the initial value of the semaphore s stands for?<br /><br />10. Show that counting semaphores can be implemented using binary semaphores.</span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-92063014152975869852007-11-24T21:05:00.000+08:002007-11-24T21:41:16.231+08:00IS215 - Resource Management Exercises - 2<span style="font-size:85%;"><span style="font-family:verdana;">11. Given a river crossing deadlock situation in Figure 6.3.</span><br /><br /><span style="font-family:verdana;">a) Name the three broad classes of policies dealing with deadlocks. Give one specific policy each to illustrate the classes using the river crossing 'deadlock situation.</span><br /><span style="font-family:verdana;">b) Illustrate the Banker's algorithm using the river crossing deadlock situation.</span><br /><br /><span style="font-family:verdana;">12. The Banker's algorithm has some inherent weaknesses. Discuss some of these inherent weaknesses.</span><br /><br /><span style="font-family:verdana;">13. Deadlock avoidance is very expensive. Why?</span><br /><br /><span style="font-family:verdana;">14. Consider the traffic deadlock depicted in Figure 6.5.<br /><br /></span> </span><div style="text-align: center;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjl9l3Q-VoOppVSVHSguO6aoePufWhYU201A3QZSV2X3A9g_K-PZnr3qL2TdBRYvy0g5apO13ST7rxIc_xKal702osa4houCfIScjcz1UbnWKyR0tTnwR6VyLe6NyxjWH0HOrfMq3EnvsRl/s1600-h/deadlock.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjl9l3Q-VoOppVSVHSguO6aoePufWhYU201A3QZSV2X3A9g_K-PZnr3qL2TdBRYvy0g5apO13ST7rxIc_xKal702osa4houCfIScjcz1UbnWKyR0tTnwR6VyLe6NyxjWH0HOrfMq3EnvsRl/s320/deadlock.JPG" alt="" id="BLOGGER_PHOTO_ID_5136395679500599602" border="0" /></a><span style="font-weight: bold;font-size:85%;" ><span style="font-family:verdana;"><br />Figure 6.5. Traffic deadlock<br /><br /></span></span> </div><span style="font-size:85%;"> <span style="font-family:verdana;">a) Show that the four necessary conditions for a deadlock indeed hold in the said situation.</span><br /><span style="font-family:verdana;">b) Come up with a simple rule that will avoid deadlocks in the streets of Metro Manila.</span><br /><br /><span style="font-family:verdana;">15. Compare the four policies for dealing with deadlocks using the following criteria:</span><br /><br /><span style="font-family:verdana;">a) overhead introduced for adopting such policy,</span><br /><span style="font-family:verdana;">b) inconvenience to users when a deadlock occurs,</span><br /><span style="font-family:verdana;">c) difficulty of implementation.</span><br /><br /><span style="font-family:verdana;">16. Differentiate a deadlock situation from starvation.</span><br /><br /><span style="font-family:verdana;">17. Consider a computer system that has four magnetic tape drives (MT), four exchangeable disk drives (DD), two line printers (LP), and two card readers (CR). Suppose the current allocation of resources to processes are:</span><br /><span style="font-family:courier new;"><br /><span style="font-family:courier new;">18. 19. P1 20. P2 21. P3 22. P4 23. Max</span><br /><span style="font-family:courier new;">24. MT 25. 0 26. 0 27. 2 28. 2 29. 4</span><br /><span style="font-family:courier new;">30. DD 31. 0 32. 0 33. 2 34. 2 35. 4</span><br /><span style="font-family:courier new;">36. LP 37. 1 38. 0 39. 0 40. 0 41. 2</span><br /><span style="font-family:courier new;">42. CR 43. 0 44. 1 45. 1 46. 0 47. 2</span><br /></span><span style="font-family:verdana;"><br />Suppose,<br /><br />P1 is waiting for DD,<br />P2 is waiting for MT, and<br />P4 is waiting for CR.<br /><br />Will a circular wait result if we allocate<br /><br />LP to P2<br />LP to P3<br />LP to P4?<br /><br />18. Why is deadlock recovery such a difficult policy to implement?<br /><br />19.If the state is unsafe, it does not follow that the system will result to a deadlock. Explain why this is the case. Give an example of an unsafe state that will result to all the processes completing without deadlock occurring.<br /><br />20. Under what circumstances would you adopt the following deadlock policies:<br />a) Bahala na<br />b) Avoidance<br />c) Detect and Recover<br />d) Prevention</span></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-35007102471580773512007-11-24T20:49:00.000+08:002007-11-24T21:42:57.351+08:00IS215 - Resource Management Exercises - 1<span style="font-size:85%;"><span style="font-family:verdana;">1. Discuss the two resource allocations methods (static and dynamic). Give the advantages of one over the other.</span><br /><br /><span style="font-family:verdana;">2. Classify the following resources as either sharable or non-sharable: CPU, memory, line printer, card reader, magnetic tape, magnetic disk, file, database record.</span><br /><br /><span style="font-family:verdana;">3. Give an example of a system in a deadlock situation. The example should be a system with at least three different types of resources.</span><br /><br /><span style="font-family:verdana;">4. Explain the four conditions for a deadlock to occur. Is it necessary for all four conditions to hold for a deadlock to occur.</span><br /><br /><span style="font-family:verdana;">5. Why does the Bahala Na policy work? Why is this policy not often used?</span><br /><br /><span style="font-family:verdana;">6. How can the circularity condition be prevented from holding? Illustrate how deadlock can be avoided by preventing this condition.</span><br /><br /><span style="font-family:verdana;">7. How can hold and wait be prevented from holding? Illustrate how deadlock can be avoided by preventing this condition.</span><br /><br /><span style="font-family:verdana;">8. One way of detecting a deadlock is to detect if circularity wait already holds in the system. </span><br /><span style="font-family:verdana;">Outline a method of detecting a deadlock.</span><br /><br /><span style="font-family:verdana;">9. Outline the cheapest method of recovering from a deadlock. Support your answer by arguing for it.</span><br /><br /><span style="font-family:verdana;">10. Aborting a process during deadlock recovery is not that simple. Explain.</span></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-27252111193601779722007-11-24T18:05:00.000+08:002007-11-24T21:37:28.637+08:00IS215 - File and Disk Management Exercises - 2<span style="font-size:85%;"><span style="font-family:verdana;">11. What method of ensuring file systems reliability is suitable for each of the following 'file system:</span><br /><br /><span style="font-family:verdana;">a) small in size and data loss is tolerable (quite cheap to recover)</span><br /><span style="font-family:verdana;">b) small and data loss are very expensive, hence it should be avoided</span><br /><span style="font-family:verdana;">c) large in size and data loss is tolerable</span><br /><span style="font-family:verdana;">d) large in size and data loss is very expensive</span><br /><br /><span style="font-family:verdana;">Explain your answer.</span><br /><br /><span style="font-family:verdana;">12. Periodic dump is expensive. Explain.</span><br /><br /><span style="font-family:verdana;">13. Discuss the procedure for recovering from file system crash, when the system used is a combination of periodic dump, incremental dump and transaction logging.</span><br /><br /><span style="font-family:verdana;">14. Name an actual system that uses the directory structure:</span><br /><br /><span style="font-family:verdana;">a) single-level directory</span><br /><span style="font-family:verdana;">b) two-level directory structure</span><br /><span style="font-family:verdana;">c) tree-structured directory</span><br /><span style="font-family:verdana;">d) acyclic directory</span><br /><br /><span style="font-family:verdana;">15. Discuss a method of checking the consistency of a file system.</span><br /><br /><span style="font-family:verdana;">16. During file system recovery after a crash, files are often compacted into contiguous regions on the disk even though such contiguity may be irrelevant to the file access method. Explain why compaction may still be advantageous.</span><br /><br /><span style="font-family:verdana;">17. Given the following requests for disk access in a disk whose tract number ranges from 0 to 99.</span><br /><br /><span style="font-family:verdana;">20, 7, 99, 56, 75, 19, 89, 2, 50</span><br /><br /><span style="font-family:verdana;">The read/write head is currently reading track number 15 and has just gone from track number 26, if the scheme used is:</span><br /><br /><span style="font-family:verdana;">a) First-Come-First-Serve</span><br /><span style="font-family:verdana;">b) Shortest-Seek-Time-First</span><br /><span style="font-family:verdana;">c) SCAN</span><br /><span style="font-family:verdana;">d) CSCAN</span><br /><span style="font-family:verdana;">e) N-Step SCAN</span><br /><br /><span style="font-family:verdana;">18. Differentiate non-contiguous sector allocation from non-contiguous block allocation.</span><br /><br /><span style="font-family:verdana;">19. What are the overheads involved with the allocation strategies: contiguous, linked, 'and indexed, if the file:</span><br /><br /><span style="font-family:verdana;">a) grows at the beginning</span><br /><span style="font-family:verdana;">b) grows at the middle</span><br /><span style="font-family:verdana;">c) grows at the end?</span><br /><br /><span style="font-family:verdana;">Answer also the cases when the file shrinks instead of grows.</span><br /><br /><span style="font-family:verdana;">20. All the disk scheduling algorithms (SSTF, SCAN, C-SCAN, N-Step SCAN) except FCFS are not truly fair (starvation may occur). Arrange the algorithms in order of degrading fairness. Show how you arrived at your answer.</span></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-84916258650317441492007-11-24T17:56:00.000+08:002007-11-24T21:44:47.310+08:00IS215 - File and Disk Management Exercises - 1<span style="font-size:85%;"><span style="font-family:verdana;">1. What is a file? Describe the three most common file organizations.</span><br /><br /><span style="font-family:verdana;">2. What is a file descriptor? What is a file directory? What is the relationship between the two?</span><br /><br /><span style="font-family:verdana;">3. What is the difference of a tree-structured directory structure from an acyclic directory structure?</span><br /><br /><span style="font-family:verdana;">4. Suppose a computer system will be used for software development of a programming team.</span><br /><br /><span style="font-family:verdana;">a) What directory system is suited for this type of system?</span><br /><span style="font-family:verdana;">b) What file protection scheme is needed to satisfy the needs of the users?</span><br /><span style="font-family:verdana;">c) What file access methods should be supported?</span><br /><span style="font-family:verdana;">d) What file allocation method should be used?</span><br /><br /><span style="font-family:verdana;">Answer the same questions for system intended as an automated teller machine (ATM).</span><br /><br /><span style="font-family:verdana;">5. Identify the minimal operations on files that will allow all other operations to be simulated using the operations in the minimal set operations.</span><br /><br /><span style="font-family:verdana;">6. One way of protecting the file system is through the use of passwords. Why is this method not used anymore in most modern operating systems?</span><br /><br /><span style="font-family:verdana;">7. Outline a method of protecting the files of a user in a multi-user operating system. The method should allow others to access the files of the user if he allows it.</span><br /><br /><span style="font-family:verdana;">8. What are the advantages of direct access to files over the sequential access to files? Are both access methods really necessary in an operating system?</span><br /><br /><span style="font-family:verdana;">9. What is the difference between sector and block file allocation methods? Is there a situation where both methods are one and the same?</span><br /><br /><span style="font-family:verdana;">10. What is the problem in contiguous allocation method that is solved by the linked allocation method?</span></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-36833837179753270132007-11-24T17:39:00.000+08:002007-11-24T21:45:36.153+08:00IS215 - Memory Management Exercises - 2<span style="font-size:85%;"><span style="font-family:verdana;">11. Discuss the factors that may affect the performance of a paging system. For each of the sequence of page requests given below, and assuming a store size of four page frames, give the optimum sequence of page fetches and replacements and also, the sequence which would be generated if the replacement algorithm used is LRU. Do the same for FIFO. Comment on the results obtained.</span><br /><br /><span style="font-family:verdana;">a) 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3</span><br /><span style="font-family:verdana;">b) 1, 2, 1, 3, 1, 4, 1, 5, 1, 2, 1, 3, 1, 4, 1, 5, 1, 2</span><br /><span style="font-family:verdana;">c) 1, 2, 3, 4, 5, 4, 3, 2, 1, 2, 3, 4, 5, 4, 3, 2, 1, 2</span><br /><span style="font-family:verdana;">d) 1, 2, 3, 4, 5, 4, 3, 2, 1, 5, 4, 3, 2, 1, 2, 3, 4, 5</span><br /><br /><span style="font-family:verdana;">12. With the sequence of page requests given in (11a-11d), give the contents of the memory for each sequence. Assume that the memory is initially empty and the working set is 4 pages at any instant.</span><br /><br /><span style="font-family:verdana;">13. Outline a possible structure for page and segment tables. Explain how an associative memory may be used to reduce effective access time. Show that if p% of accesses fail to match entries in the associative store then, in a page segmented addressing system, there will be a slow down of p%.</span><br /><br /><span style="font-family:verdana;">14. Local page replacement policy is prone to thrashing. Argue for or against this statement.</span><br /><br /><span style="font-family:verdana;">15. Paged segmentation was designed to combine the advantages of paging and segmentation. Hence there are problems present in</span><br /><br /><span style="font-family:verdana;">a) paging alone; and</span><br /><span style="font-family:verdana;">b) segmentation alone</span><br /><br /><span style="font-family:verdana;">which are not in paged segmentation. List all these problems.</span><br /><br /><span style="font-family:verdana;">16. Demand and anticipatory fetch policies can be combined together. Outline a system that combines these two fetch policies.</span><br /><br /><span style="font-family:verdana;">17. Discuss how thrashing is avoided when the working set of a process is determined in advance.</span><br /><br /><span style="font-family:verdana;">18. Consider a swapping system. Measured utilization are:</span><br /><br /><span style="font-family:verdana;">CPU utilization - 20%</span><br /><span style="font-family:verdana;">Swapping device (drum) - 99.7%</span><br /><span style="font-family:verdana;">Other I/O devices - 5%</span><br /><br /><span style="font-family:verdana;">What will be the effect on CPU utilization if we</span><br /><br /><span style="font-family:verdana;">a) get a faster CPU</span><br /><span style="font-family:verdana;">b) get a bigger hard disk for swapping</span><br /><span style="font-family:verdana;">c) increase the degree of multiprogramming</span><br /><span style="font-family:verdana;">d) decrease the degree of multiprogramming</span><br /><span style="font-family:verdana;">e) get faster other I/O devices.</span><br /><br /><span style="font-family:verdana;">19. Consider a swapping system in which the memory is composed of the following hole sizes (assuming the leftmost hole is the first in the list):</span><br /><br /><span style="font-family:verdana;">10K, 4K, 20K, 18K, 9K, 12K, 15K</span><br /><br /><span style="font-family:verdana;">Which hole is taken for successive segment=requests of 12K, 5K, 10K for first-fit? Repeat the question for best-fit and worst-fit.</span><br /><br /><span style="font-family:verdana;">20. Which of the following programming techniques and structures are ideal for paging. Support your answer.</span><br /><br /><span style="font-family:verdana;">a) sequential search</span><br /><span style="font-family:verdana;">b) binary search</span><br /><span style="font-family:verdana;">c) array operations</span><br /><span style="font-family:verdana;">d) stack operations</span><br /><br /><span style="font-family:verdana;">Which is ideal for segmentation?</span></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-27556652194500287432007-11-24T16:38:00.000+08:002007-11-24T21:45:59.712+08:00IS215 - Memory Management Exercises - 1<span style="font-size:85%;"><span style="font-family:verdana;">Exercises</span><br /><br /><span style="font-family:verdana;">1. When binding of addresses to memory locations is done at execution time, relocation 'is less expensive than when binding is done at compile time. Explain.</span><br /><br /><span style="font-family:verdana;">2. The main problem of Multiprogramming with Fixed Number of Tasks is internal fragmentation while that of Multiprogramming with Variable Number of Tasks is external fragmentation. Explain.</span><br /><br /><span style="font-family:verdana;">3. Define swapping. What are the motivations for providing swapping? Show how this technique enables a reasonable response time to be given to each user of an interactive system. In what situation is swapping not effective?</span><br /><br /><span style="font-family:verdana;">4. Why is CPU utilization improved when swapping is upgraded from that where only one user process is allowed in memory at a time to one where more than one user process is allowed in memory at a time.</span><br /><br /><span style="font-family:verdana;">5. Outline one method of protecting the memory of a multi-user system. Specifically answer the question of how to protect the systems area (without totally preventing other users from accessing the said area as long as it is done correctly) and the areas allocated to other users.</span><br /><br /><span style="font-family:verdana;">6. Compaction usually introduces a high overhead because it has to consider the binding of user's variables to memory locations. Explain.</span><br /><br /><span style="font-family:verdana;">7. Differentiate temporal from spatial locality. Illustrate the two using access to the memory by the computer system.</span><br /><br /><span style="font-family:verdana;">8. Why is it impossible to share the code of a process that allows modification on the code itself.</span><br /><br /><span style="font-family:verdana;">9. Given the following segment table:</span><br /><span style="margin: 0pt 5px; padding: 0pt 5px; text-align: left;font-family:verdana;" ><table style="margin: 0pt 5px;"><tbody><tr><th>Segment Number</th><th>Base</th><th>Limit</th></tr><tr><td>0</td><td>50</td><td>150</td></tr><tr><td>1</td><td>1000</td><td>100</td></tr><tr><td>2</td><td>500</td><td>200</td></tr><tr><td>3</td><td>250</td><td>50</td></tr></tbody></table></span><br /><span style="font-family:verdana;">What are the equivalent real addresses of the following virtual addresses:</span><br /><br /><span style="font-family:verdana;">a) (0, 10)</span><br /><span style="font-family:verdana;">b) (1, 150)</span><br /><span style="font-family:verdana;">c) (2,100)</span><br /><span style="font-family:verdana;">d) (3, 25)</span><br /><br /><span style="font-family:verdana;">10. Assuming a page frame size of 1024 and given the following page table:</span><br /><span style="margin: 0pt 5px; padding: 0pt 5px; text-align: left;font-family:verdana;" ><table style="margin: 0pt 5px;"><tbody><tr><th>Page Number</th><th>Base</th></tr><tr><td>0</td><td>1024</td></tr><tr><td>1</td><td>3072</td></tr><tr><td>2</td><td>5120</td></tr><tr></tr><tr><td>3</td><td>2048</td></tr></tbody></table></span><br /><span style="font-family:verdana;">What are the equivalent real addresses of the following virtual addresses:</span><br /><span style="font-family:verdana;">a) (0, 64)</span><br /><span style="font-family:verdana;">b) (1, 1048)</span><br /><span style="font-family:verdana;">c) (2, 1)</span><br /><span style="font-family:verdana;">d) (3, 1024)</span><br /><br /></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-29534015895357004062007-11-24T06:22:00.000+08:002007-11-25T17:35:34.686+08:00IS215 - Processor Management Exercises - 2<script type="text/Javascript"> function expandcollapse (postid) { whichpost = document.getElementById(postid); if (whichpost.className=="textshown") { whichpost.className="texthidden"; } else { whichpost.className="textshown"; } } </script><span style=";font-family:verdana;font-size:85%;" >11. Explain what is a fair scheduling algorithm?<br /><br />12. What are the objectives of CPU scheduling?<br /><span style="font-family:verdana;"><br /><a href="javascript:expandcollapse('question12')">Answer</a></span><br /><span class="texthidden" id="question12" style="font-family:verdana;">The main objective of CPU scheduling is "to allocate the CPU so as to optimize system performance without sacrificing user convenience... To achieve the objective of CPU scheduling, we need to provide a good performance using the measures outlined above, meet user specified deadlines, and provide good utilization of other system resources."<br /></span><br />13.Describe the advantages and disadvantages of two short-term scheduling policies that could be used to select which process next enters the run state.<br /><br />14. State an undesirable feature associated with each of the following scheduling algorithms:<br />a) First-come-first-serve<br />b) Shortest job first<br />c) Shortest remaining processing<br /><br />15. Round robin schedulers normally maintain a list of all runnable processes, with each process occurring exactly once in the list. What would happen if a process occurred twice in the list? Can you think of any reason for allowing this?<br /><br />16. When is the response time of a process different from its waiting time.<br /><br />17. Most operating systems usually use a two-level scheduler.<br />a) Give two advantages of this set-up.<br />b) Give two disadvantages of this set-up.<br />c) Describe the actions of a two-level scheduler when it is called to select a process to be dispatched.<br /><br />18. Minimizing mean response time is the same as maximizing throughput. Prove this 'statement.<br /><br />19. Evaluate the scheduling algorithms<br />a) First-Come-First-Serve<br />b) Shortest Job Next<br />c) Shortest Remaining Processing Time<br /><br />in terms of the following criteria:<br />CPU utilization<br />throughput<br />turnaround time<br />waiting time.<br /><br />20. Short time slices means better response times. Explain why this is so?</span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-44600883072841772922007-11-24T06:01:00.000+08:002007-11-25T17:28:41.339+08:00IS215 - Processor Management Exercises - 1<script type="text/Javascript"> function expandcollapse (postid) { whichpost = document.getElementById(postid); if (whichpost.className=="textshown") { whichpost.className="texthidden"; } else { whichpost.className="textshown"; } } </script><span style="font-style: italic;font-family:verdana;font-size:85%;" >Making use of the decryption routine before, I took the exercises contents in the single processor PDF for a ride. However it turned out that the text in text areas don't render pasted text from the clipboard properly especially for non-alphanumeric characters. If I end up having free time soon, I'll try and refine the functionality further. Right now, I need to sleep already.<br /><br />Anyway, here are the exercises for the processor management chapter after a few tweaks from the resulting text:</span><br /><br /><span style=";font-family:verdana;font-size:85%;" >1. Providing good response time at a terminal might introduce large overheads that in effect will reduce the overall CPU utilization. Explain what are these overheads that will reduce CPU utilization.<br /><br />2. When we view all the processes in the system, we can see that a state transition by one process could cause another process to make a state transition. Under what circumstances, if any, could the following cause-and-effect transitions occur?<br /><br />a) block -> dispatch<br />b) preempt -> dispatch<br /><span style="font-family:verdana;">c) block -> preempt</span><br /><span style="font-family:verdana;">d) wake-up -> dispatch</span><br /><br /><span style="font-family:verdana;">3. Under what circumstances, if any, would the following transitions cause no other immediate transitions:</span><br /><br /><span style="font-family:verdana;">a) dispatch</span><br /><span style="font-family:verdana;">b) preempt</span><br /><span style="font-family:verdana;">c) block</span><br /><span style="font-family:verdana;">d) wake-up</span><br /><br /><span style="font-family:verdana;">4. Differentiate preemptive from non-preemptive scheduling in terms of when to change the program currently in control of the CPU.</span><br /><span style="font-family:verdana;"><br /><a href="javascript:expandcollapse('question04')">Answer</a></span><br /><span class="texthidden" id="question04" style="font-family:verdana;">Preemptive scheduling refers to a scheduling strategy where "the CPU is suspended when a higher priority process is in the ready queue" while non-preemptive scheduling refers to a scheduling strategy where "even if a higher priority process is ready, the running process is allowed to continue until either it is blocked or completes its execution."<br /></span><br /><span style="font-family:verdana;">5. When no process is ready to take control of the CPU, we need to have something to keep the CPU busy. Why?</span><br /><br /><span style="font-family:verdana;">6. State the effect of</span><br /><br /><span style="font-family:verdana;">a) time slicing; and</span><br /><span style="font-family:verdana;">b) increasing the time for one interaction<br /><br />on the response time of a process.</span><br /><br /><span style="font-family:verdana;">7. What is the purpose of a dispatcher in an operating system? Illustrate your answer by showing the sequence of events and dispatcher actions that occur when a process enters the run state from the ready state.</span><br /><br /><span style="font-family:verdana;">8. Differentiate high-level scheduling of jobs and low-level scheduling of processes.</span><br /><span style="font-family:verdana;"><br /><a href="javascript:expandcollapse('question08')">Answer</a></span><br /><span class="texthidden" id="question08" style="font-family:verdana;">High-level scheduling of jobs refers to swapping processes in and out of memory. Issues concerning high-level scheduling include deciding if another process can still run, whether the process table is full, whether the user process limit has been reached and whether to load to swap space or memory. Low-level scheduling on the other hand refers to deciding which process in memory should get CPU time next.<br /></span><br /><span style="font-family:verdana;">9. The scoring system in high-level scheduling usually "age". Why is there a need to "aged" the scores?</span><br /><br /><span style="font-family:verdana;">10. Short-term scheduling can either be preemptive or non-preemptive. Differentiate these two methods of short-term scheduling.</span><br /></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-46784488924331102022007-11-22T01:02:00.000+08:002007-11-22T10:21:38.478+08:00PDF Encryption<script type = "text/javascript"> function decryptText() { var enc = document.getElementById( "encrypted_content" ); var strContent = enc.value; var strResult = ''; n = strContent.length; i = 0; for ( ; i < n; i++ ) strResult = strResult + String.fromCharCode( ( strContent.charCodeAt( i ) + 29 ) % 256 ); enc.value = strResult; } </script><span style="font-family: verdana;font-size:85%;" ><span style="font-weight: bold;font-size:100%;" >Messing It Up</span><br /><br />One thing frustrating I encountered when copy-pasting stuff from the Single Processor PDF was that things messed up during the paste-part. To see this, try highlighting the a few words or line of texts from the said PDF.</span><br /><span style="font-size:85%;"><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7BGOrlWbz4fuSoQKl8fQv21eLNApariZQYzDDs3cF48cRIQFZ6HaBgE56DQyQrRDT0Pqv9wV_8UkgBPGxPX745taaQjvmpNF3-HDUxZpNpOD12DkrJVhfYvKxEkq-01II9Zqmi8CHvjtc/s1600-h/scrnshot1.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7BGOrlWbz4fuSoQKl8fQv21eLNApariZQYzDDs3cF48cRIQFZ6HaBgE56DQyQrRDT0Pqv9wV_8UkgBPGxPX745taaQjvmpNF3-HDUxZpNpOD12DkrJVhfYvKxEkq-01II9Zqmi8CHvjtc/s320/scrnshot1.JPG" alt="" id="BLOGGER_PHOTO_ID_5135373906780881170" border="0" /></a><br /><span style="font-family: verdana;font-size:85%;" >Then pasting it in any word processor or text editor produces garbage. The next screenshot was how it appeared in Notepad++ here.<br /><br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-mTVxvoLI08FjFRoOAqqEpCqqwarQA2ykFT2ap-Ztm4DL4GjnIhOAachrGFhcZjkWYDcpRMN0qhRzdYUq6w4pmRwesNymC4JtDmPqYpT5fiHe-kVYWq1k-77KUx07vLYH-CwEBZ3Cyz3i/s1600-h/scrnshot2.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-mTVxvoLI08FjFRoOAqqEpCqqwarQA2ykFT2ap-Ztm4DL4GjnIhOAachrGFhcZjkWYDcpRMN0qhRzdYUq6w4pmRwesNymC4JtDmPqYpT5fiHe-kVYWq1k-77KUx07vLYH-CwEBZ3Cyz3i/s320/scrnshot2.JPG" alt="" id="BLOGGER_PHOTO_ID_5135374731414602018" border="0" /></a><br /><span style="font-family: verdana;font-size:85%;" >Not good especially if copy-paste saves a lot of time. And today's just two days before the deadline! If I just had the time, I would've even bothered to create at least an equivalent Word document for easier searching of terms and concepts if the time still permitted.<br /></span><br /><br /><span style="font-family: verdana;font-size:85%;" ><span style="font-weight: bold;font-size:100%;" >Workarounds Anyone?<br /><br /></span></span><span style="font-family: verdana;font-size:85%;" >Now I don't know if there are any third-party software for this one. What I do know is that the mapping's pretty obvious. You might want to try and comparing ASCII values of characters from several encrypted and decrypted samples. If you do so, you'll end up with:<br /><br />y = ( x + 29 ) mod 256<br /><br />Nothing much useful there though except if it can be used without the calculator and ASCII table.<br /><br />So I actually spent time to create a working decryption form for it, (a horribly crude but functional one that is.) So after a few lines of Javascript and HTML code, it worked!<br /><br />Check it out below.</span><br /><br /><textarea name="encrypted_content" id="encrypted_content" rows="4" cols="35">Your Encrypted Text Goes Here...</textarea><br /><br /><a href="javascript:decryptText()">Decrypt Now</a>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0tag:blogger.com,1999:blog-8591021297729527124.post-25477268950110744412007-11-22T00:32:00.000+08:002007-11-22T00:57:22.764+08:00What's With The New Blog?<span style="font-family: verdana;"><span style="font-size:85%;">Just another attempt at organizing MIS routines.<br /><br />Since I just started with my MIS studies at UPOU, I've had less time for my other blogs, (<a href="http://patrickestrella.wordpress.com">Half-Empty, Half-Full</a> and <a href="http://dominoeffect.wordpress.com">The Domino Effect</a> both at <a href="http://www.wordpress.com">Wordpress</a>). It might seem a little odd then that one of the reasons I chose to fix my already crazy schedule is to create yet another one.<br /><br />But what can I do, I have to start organizing stuff somewhere. At the rate regular and freelance work along with family responsibilities pour in, I can't make a dedicated and specialized online storage for the things the way I want it. Throw in the slow yet merciless ticking of the clock and I have to make my move now.<br /><br />Why the Blog? Because I don't have the time to create a CMS for the stuff, not even something half-baked. Sure there are several-minute-setup CMS services out there but I'm more used to blogging. Perhaps a move elsewhere in the future might be in order but for now, this should do.<br /><br />Why <a href="http://www.blogger.com">Blogger</a>? I find the functionalities of Wordpress too constraining especially the lack of support for some HTML and Javascript, especially for the latter. Since I intend to include some functionalities here, the lack of client-side scripting appears glaring.<br /><br />So after a deep breath, here goes nothing...<br /></span></span>Patrickhttp://www.blogger.com/profile/09306667977156055687noreply@blogger.com0