Interrupt and a Trap in an Operating System Essay Example for Free

Interrupt and a Trap in an Operating System Essay What are the differences between an interrupt and a trap? What are their importance? According to Stallings (2012) an interrupt is â€Å"a suspension of a process, such as the execution of a computer program, caused by an event external to that process and performed in such a way that the process can be resumed† (p. 716). Stallings (2012) goes on to say that â€Å"interrupts are provided primarily as a way to improve processor utilization. For example, most I/O devices are much slower than the processor† (p. 14). â€Å"A trap is an unprogrammed conditional jump to a specified address that is automatically activated by hardware; the location from which the jump was made is recorded† (Stallings, 2012, p. 721). A trap is actually a software generated interrupt caused either by an error (for example division by zero, invalid memory access etc.), or by a specific request by an operating system service generated by a user program. Trap is sometimes called Exception. The hardware or software can generate these interrupts. When the interrupt or trap occurs, the hardware transfers control to the operating system which first preserves the current state of the system by saving the current CPU registers content and program counters value. Then the focus shifts to the determination of which type of interrupt has occurred. For each type of interrupt, separate segments of code in the operating system determine what action should be taken and thus the system keeps on functioning by executing computational instruction, I/O instruction, storage instruction etc. Provide an example of each. Example of an Interrupt retrieved from http://www.scriptoriumdesigns.com/embedded/show_codefile.php?fname=interrupts/AVR_ISR_1.c // AVR_ISR_1 #include avr/io.h #include avr/interrupt.h typedef uint8_t u8; // convenient unsigned variable designations typedef uint16_t u16; #define INPORT PIND #define OUTPORT PORTC #define OUTDDR DDRC volatile u8 Int_flag = 0; ISR( INT0_vect ) { OUTPORT ^= 0x01; // toggle LED } void int0_init( void ) { MCUCR = (1ISC01); // enable negative edge on INT0 GICR = (1INT0); // enable INT0 } int main( void ) { OUTDDR = 0x01; // set bit 0 to output OUTPORT = 0x01; // set LED off (active low) int0_init(); // configure INT0 sei(); // enable global interrupts while (1) // loop forever, all work happens in ISR ; return(0); Example of a trap retrieved from http://www.ibm.com/developerworks/aix/library/au-usingtraps/index.html #!/bin/bash # proj_dir=/opt/pcake/bin # check file is present if [ ! -f $proj_dir/run_pj ] then echo $proj_dir/run_pj not presentexiting exit 1 fi # make a backup copy cp -p $proj_dir/run_pj $proj_dir/run_pj.24042011 if [ $? != 0 ] then echo $proj_dir/run_pj no backup madeexiting exit 1 fi # copy over updated file if [ ! -f /opt/dump/rollout/run_pj ] then echo /opt/dump/rollout/run_pj not presentexiting exit 1 fi cp -p /opt/dump/rollout/run_pj $proj_dir/run_pj if [ $? != 0 ] then echo $proj_dir/run_pj was not copied..exiting exit 1 fi References: Stallings, W. (2012). Operating systems: Internals and design principles (7th ed.). Boston, MA: Prentice Hall.

Iranian Education Essay -- Iran Middle East

Iranian Education: From Modernization to Traditionalism An education system, because of its purpose as the shaper of the future, is a good indicator of what is going on within a country politically and culturally. The history of the Iranian education system showed change as the ideological values of the country shifted with each new regime change in the mid twentieth century. Iran, as a country, went from a country focused on modernization and secularization under the Reza Shah, to a country focused on traditional Islamic values under the new government established after the Islamic Revolution of 1977-791. These changes shifted the very purpose of education, its impact on women (in arguably negative or positive ways), and its literature. The shift in political focus from modernism to religious traditionalism can also be seen in how religion is taught in Iran, especially compared with different countries around the world. The history of the Iranian education system from 1907-1977 is one that is filled with problems. In 1907, Iran established a Ministry of Science and Art to control all areas of education, even religious education. In 1910, this ministry was reorganized and renamed the Ministry of Education, and given more power to set laws and guidelines for education, religious and secular. This body was not necessarily effective in setting new guidelines for Iranian schools. The main problem was overcoming was the lack of qualified, quality teachers (Szyliowicz 176- 7). After 1925, the Shah2 built many new schools and tried to revitalize the educational system. This effort was hampered again, by lack of qualified teachers (Szyliowicz 231), a lack of coherent ideology (Szyliowicz 232), and a program of edu... ...ern Iran. Ithaca and London: Cornell University Press, 1992. Rivard, Jean-Franà §ois and Massimo Amadio. â€Å"Teaching Time Allocated to Religious Education in Official Timetables.† Prospects 33 (2003): 211-217. Shavarini, Mitra K. â€Å"Misconceptions about Islam and Women’s Education: Lessons learned from the Islamic Republic of Iran (IRI).† International Education. 33.1 (Fall 2003): 40(11). Gender Watch. Proquest. Univ Mass Amherst. 10 Feb 2006. . Szyliowicz, Joseph S. Education and Modernization in the Middle East. Ithaca and London: Cornell University Press, 1973. UNESCO. Integration of Technology and Vocational Education into Special Needs Education. Austria, Colombia, Iran, Tunisia. Geneva: Imprimeries Popularies, 1977. Zia, Rukhsana. â€Å"Religion Education in Pakistan: An Overview.† Prospects. 22 (2003): 165-178.

Weekly Routine

I am an engineer. My company is in Longtan Science Park. I live in Nan Kan. It’s a little far from my company and I have to drive a car to company every day. I get up at 7:00 a. m. and next I will try to wake my daughter up after ten minutes’ shower and set the television to cartoons in order to have her attention and it is painful to let her awaken during that time. I send my daughter to her kindergarten before I send my wife to the bus stop to take bus to Taipei. Then I buy breakfast at McDonald's drive-through and finally get on he highway to company, it’s about 8 o’clock usually. I arrive at company after 30 minutes’ drive. After a short break to catch my breath, I wipe my desk firstly and turn on my computer to check the emails for a while. Second, I go pantry room to have a cup of coffee before the weekly meeting at 10 o’clock and in general, the meeting will not finish until lunch time and it always depress me on Monday morning. I come back to work at 1:30 after taking a lunch break and my work ends at 5:30 p. m. Then I go home and spend a good time with my family except for Tuesday and Wednesday due to learning English in Trinity. I will turn on the air condition as soon as I arrive home and then I hasten restroom to wash my daughter’s hands and myself. My daughter starts to watch TV at 8:30 and it’s hard to extract her from it until 9 o’clock. Later I commence to review her lessons and it takes me half hour. Then I wheedle her into sleep and she falls asleep by 10 o’clock. I have my private time after she gets to sleep and ometimes I go internet and kill time and I go to bed at 12 finally. Daily life is almost the same and unchangeable on weekdays but I live a life of diverseness on weekends. I will not get up until 10 o’clock and after that I go brunch with my wife and daughter. We will tour by car or go for an outing somewhere to enjoy our vacation in the afternoon and then go to a restaurant to taste delicacies with family love and joy. I think I am the happiest father in the world as soon as I see the fulfilled smiles of my daughter at that time.

Spelling Bee Descriptive Essay - 731 Words

One chilly December morning, I was walking into my school, reading a spelling book, cuddling inside my warm woolen jacket. Little did I know that I walked into a wall, â€Å"Ow!† I shrieked. I rubbed my forehead and went back to reading and memorizing my spelling book. Today was our school’s annual spelling bee competition. I suddenly remembered that I had better get to my classroom fast. I ran as fast as I could with a heavy backpack, a lunchbox, and a bulky woolen jacket. I got there just in time for the line-up. I shoved my backpack and lunchbox under my desk and threw my jacket onto my chair. I scurried after the line to the auditorium. My name was called after many others. I nervously walked up to the stage, wishing I had never been†¦show more content†¦I spelled inside my head â€Å"Subdermatoglyphic† and was getting nervous. The judge said, â€Å"I will say the same to you and Maia Diaval, and I am guessing this will be a neck to neck competitio n†. Maia Diaval had to spell the word, and if she had gotten it wrong. I had to spell the word too but wasn’t ready to do so. I stalled by asking a few questions. â€Å"Um, would you tell me what kind of word it is†, I asked. The judge said,† It is an Isogram, a word in which every letter is only used once† I questioned, â€Å"Well, would you tell me the definition, please† I hope he did not know about me stalling. He gave me the definition,† The underlying dermal matrix that determines the pattern formed by whorls, arches, and ridges of our fingerprints†. I then asked him, â€Å"May you put it in a sentence?† I knew that I had to figure the word out fast. The judge in his British accent said, â€Å"Have you ever looked at your finger’s Subdermatoglyphic†. Next, I asked him, â€Å"Is the part of speech provided? If yes, what is the part of speech?† I knew that I had been stalling for over few minutes and I could tell that everyone was getting impatient. The judge answered â€Å"No, it, well†¦it has not been provided†. He then asked me â€Å"will you spell the word, Subdermatoglyphic,† I asked him to repeat the word. I wrote the word, â€Å"S.U.B.D.E.R.M.A.T.O.G.L.Y.P.H.I.C†, on my hand, which is the technique I use for spelling, my Dad taught me this trick. I nervously spelled â€Å"S.U.B.D.E.R.M.A.T.O.G.L.Y.P.H.I.C†Show MoreRelatedLogical Reasoning189930 Words   |  760 Pagesprobable good consequences of each action and the probable bad consequences while weighing the positive and negative impact of each consequence. It’s a kind of cost-benefit analysis. Exercises 1. Columbus Day is an American holiday. Write a short essay that weighs the pros and cons and then comes to a decision about whether there should be more or less public celebration (by Americans and their institutions) on Columbus Day, October 12. Here is some relevant background information to reduce yourRead MoreIgbo Dictionary129408 Words   |  518 Pagesillustrated the meaning and use of words; the great majority of the examples are due to him. Their merit is that they are not translations from English, but natural Igbo sentences elicited only by the stimulus of the word they illustrate. The short essays which appear from time to time (e.g. under otà ¹tà ¹, à ²Ã¯â‚¬ ¤gbanÌ„je) on aspects of culture are also his work, as are the sketches which served as basis for the illustrations, a large number of new words, and various features of the arrangement. When he hadRead MoreStephen P. Robbins Timothy A. Judge (2011) Organizational Behaviour 15th Edition New Jersey: Prentice Hall393164 Words   |  1573 PagesGroves Senior Operations Supervisor: Arnold Vila Operations Specialist: Cathleen Petersen Senior Art Director: Janet Slowik Art Director: Kenny Beck Text and Cover Designer: Wanda Espana OB Poll Graphics: Electra Graphics Cover Art: honey comb and a bee working / Shutterstock / LilKar Sr. Media Project Manager, Editorial: Denise Vaughn Media Project Manager, Production: Lisa Rinaldi Full-Service Project Management: Christian Holdener, S4Carlisle Publishing Services Composition: S4Carlisle Publishing