PPT-Void safety

these slides contain advanced material and are optional The inventor of null references I call it my billiondollar mistake It was the invention of the null reference in 1965 At that time I was designing the first comprehensive type system for references in an object oriented language ALGOL W My goal was to ensure that all use of references should be absolutely safe with checking performed automatically by the compiler But I couldnt resist the temptation to put in a null reference simply because it was so easy to implement This has led to innumerable errors vulnerabilities and system crashes which have probably caused a billion dollars of pain and damage in the last forty years . these slides contain advanced . material and are optional. The inventor of null references. I call it my billion-dollar mistake. It was the invention of the null reference in 1965. At that time, I was designing the first comprehensive type system for references in an object oriented language (ALGOL W). My goal was to ensure that all use of references should be absolutely safe, with checking performed automatically by the compiler. But I couldn't resist the temptation to put in a null reference, simply because it was so easy to implement. This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years. . David Brumley. Carnegie Mellon University. Our story so far…. 2. U. nauthorized. C. ontrol. I. nformation. T. ampering. http://. propercourse.blogspot.com. /2010/05/. i. -believe-in-duct-. tape.html. 15-213 / 18-213: Introduction to Computer Systems. 25. th. Lecture, Nov. . 21, 2013. Instructors:. . Randy Bryant, Dave . O’Hallaron, . and . Greg . Kesden. Review: . Semaphores. Semaphore. :. . What is function? Look the example…. #include<. stdio.h. >. void main( ). {. int. . x,y. ;. float w;. char . ch. ;. scanf. (“%d %. d”,&x,&y. );. scanf. (“%f ”,&w);. scanf. 367.912 -- Waiver deemed void. (1) Any contract which does not comply with the a pplicable provisions of KRS 367.900 to 367.930 shall be void and unenforceable as contrary to public policy. (2) Any w GCC4.7.0-O2:theabovecodesometimesprints0! 2/28 CcodeAssemblygeneratedintfunc_1(void){intl;for(l=0;(l!=4);l++){if(g_1)returnl;for(g_2=0;(g_2=26);++g_2);}}func_1:movlg_1(%rip),%edxmovlg_2(%rip),%eaxtes 15-213 / 18-213: Introduction to Computer Systems. 25. th. Lecture, Nov. . 27, 2012. Instructors:. . Dave O’Hallaron, Greg Ganger, and Greg . Kesden. Today. Races. Locking and Deadlocks. Producer-consumer problem. -. A Brief Analysis. By Nupur Thapliyal. “I like not fair terms and a villains mind.”. -William Shakespeare (in The merchant of Venice). WHAT IS AN AGREEMENT?. Sec2 (e) . Every promise and every set of promises, forming the consideration for each is an agreement.. Selection Sort. Insertion Sort. Merge Sort. Quick Sort. Bubble Sort is the simplest sorting algorithm that works by repeatedly swapping the adjacent elements if they are in wrong order.. Worst and Average Case Time Complexity: . Gal Diskin / Intel. (. @. gal_diskin. ). Hack.lu 2011. Legal Disclaimer. INFORMATION IN THIS DOCUMENT IS PROVIDED “AS IS”. NO LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT.  INTEL ASSUMES NO LIABILITY WHATSOEVER AND INTEL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY, RELATING TO THIS INFORMATION INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT.. 15-213 / 18-213: Introduction to Computer Systems. 25. th. Lecture, Nov. 20, 2018. Reminder: Semaphores. Semaphore:. . non-negative global integer synchronization variable. Manipulated by . P . and . 15-213 / 18-213: Introduction to Computer Systems. 24. th. Lecture, Nov. 18, 2014. Instructors:. . Greg Ganger, Greg . Kesden. , and Dave . O’Hallaron. Today. Races. Locking and Deadlocks. Producer-consumer problem. Outline. Void-safety. Problem of void-calls. A solution to void-calls. Attached types. Certified attachment patterns. Object test. Void-safety in other languages. For detailed information, see. “Avoid a Void: The eradication of null dereferencing”. Agreements . in which a part of consideration or object is . unlawful—. This is mentioned in Section 24 of the Act. The basic essence of this statement is that if the consideration, as a whole or in part is unlawful or if the end product of the agreement is illegal then the agreement is declared void. The contract would, however, be considered valid after deleting the unlawful clauses.