Skip to main content

PROBLEM SOLVING AND PYTHON PROGRAMMING QUIZ

1) What is the first step in problem-solving? A) Writing code B) Debugging C) Understanding the problem D) Optimizing the solution Answer: C 2) Which of these is not a step in the problem-solving process? A) Algorithm development B) Problem analysis C) Random guessing D) Testing and debugging Answer: C 3) What is an algorithm? A) A high-level programming language B) A step-by-step procedure to solve a problem C) A flowchart D) A data structure Answer: B 4) Which of these is the simplest data structure for representing a sequence of elements? A) Dictionary B) List C) Set D) Tuple Answer: B 5) What does a flowchart represent? A) Errors in a program B) A graphical representation of an algorithm C) The final solution to a problem D) A set of Python modules Answer: B 6) What is pseudocode? A) Code written in Python B) Fake code written for fun C) An informal high-level description of an algorithm D) A tool for testing code Answer: C 7) Which of the following tools is NOT commonly used in pr...

Recovery from deadlock

Recovery From Deadlock
There are three basic methods to recovery from deadlock:
i) Inform the system operator, and allow him/her to take manual intercession.
ii) End one or more processes involved in the deadlock
iii) Preempt resources.
Process Termination
1) Two basic methods, both of which recover resources allocated to ended processes:
i) End all processes involved in the deadlock. This definitely solves the deadlock, but at the expense of ending more processes than would be absolutely necessary.
ii) End processes successively until the deadlock is fragmented. This is more conservative, but needs doing deadlock detection after each step.
2) In the latter case there are many factors that can go into deciding which processes to end next:
i) Process priorities.
ii) How long the process has been running, and how close it is to completing.
iii) How many and what type of resources is the process possession. ( Are they easy to prevent and restore? )
iv. How many more resources does the process need to finished.
v. How many processes will need to be ended
vi. Whether the process is relative or batch.
Resource Preemption
When preempting resources to reduce deadlock, there are three important issues to be addressed:
Selecting a victim - Deciding which resources to prevent from which processes involves many of the same decision criteria outlined above.
Rollback - Ideally one would like to roll back a prevented process to a safe state prior to the point at which that resource was originally allocated to the process. Unfortunately it can be difficult or 
impossible to determine what such a safe state is, and so the only safe rollback is to roll back all the way back to the origin. (I.e. remove the process and make it start over.)
Starvation - How do you guarantee that a process won't starve because its resources are always being prevented? One option would be to use a priority system, and increase the priority of a process every time its resources get prevented. Eventually it should get a high enough priority that it won't get prevented any more.


Popular posts from this blog

Introduction to C Programs

INTRODUCTION The programming language ‘C’ was developed by Dennis Ritchie in the early 1970s at Bell Laboratories. Although C was first developed for writing system software, today it has become such a famous language that a various of software programs are written using this language. The main advantage of using C for programming is that it can be easily used on different types of computers. Many other programming languages such as C++ and Java are also based on C which means that you will be able to learn them easily in the future. Today, C is mostly used with the UNIX operating system. Structure of a C program A C program contains one or more functions, where a function is defined as a group of statements that perform a well-defined task.The program defines the structure of a C program. The statements in a function are written in a logical series to perform a particular task. The most important function is the main() function and is a part of every C program. Rather, the execution o...

Performance

Performance ( Optional ) * The I/O system is a main factor in overall system performance, and can place heavy loads on other main components of the system ( interrupt handling, process switching, bus contention, memory access and CPU load for device drivers just to name a few. ) * Interrupt handling can be relatively costly ( slow ), which causes programmed I/O to be faster than interrupt driven I/O when the time spent busy waiting is not excessive. * Network traffic can also loads a heavy load on the system. Consider for example the sequence of events that occur when a single character is typed in a telnet session, as shown in figure( And the fact that a similar group of events must happen in reverse to echo back the character that was typed. ) Sun uses in-kernel threads for the telnet daemon, improving the supportable number of simultaneous telnet sessions from the hundreds to the thousands.   fig: Intercomputer communications. * Rather systems use front-end processor...

HEAT AND THERMODYNAMICS

Heat: * Temperature is the thermal state of the body, that chooses the direction of flow of heat.  * “Heat is a form of energy transfer between two systems or a system and its surroundings due to temperature difference between them.  Specific heat capacity  * Specific heat capacity of a substance is determined as the quantity of heat required to raise the temperature of 1 kg of the substance through 1K. Its unit is J kg^–1K^–1. * The specific heat capacity of water is the highest for any substance, 4180 J/kg K. It is 30 times the specific heat capacity  of mercury which is about 140J/kg K.  Specific Latent Heat  Specific Latent Heat of fusion of any substance is the quantity of heat energy needed to melt one kilogram of a substance without change in temperature. The symbol used is L. The unit for specific  latent heat is Joule/kilogram or J/kg  The Gas Laws  * Boyle’s Law  “Temperature remaining constant, the pressure of a given mass of ...