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...
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.
* Rather systems use front-end processors to off-load some of the work of I/O processing from the CPU. For example a terminal concentrator can multiply with hundreds of terminals on a single port on a large computer.
* Several principles can be employed to improve the overall efficiency of I/O processing:
1. Reduce the number of context switches.
2. Reduce the number of times data must be copied.
3. Reduce interrupt frequency, using large transfers, buffering, and polling where
appropriate.
4. Increase concurrency using DMA.
5. Move processing primitives into hardware, allowing their operation to be
concurrent with CPU and bus operations.
6. Balance CPU, memory, bus, and I/O operations, so a bottleneck in one does not idle all the others.
* The development of new I/O algorithms frequently follows a progression from application level code to on-board hardware implementation, as shown in Figure. Lower-level executions are faster and more efficient, but higher-level ones are more adaptable and easier to modify. Hardware-level functionality may also be difficult for higher-level authorities (e.g. the kernel ) to control.
