Developers often think of software quality in terms of faults and failures. faults are problems (for example, loops that never terminate or misplaced commas in statements) that developers can see by looking at the code. failures are problems, such as a system crash or the invocation of the wrong function, that are visible to the user. thus, faults can exist in programs but never become failures, because the conditions under which a fault becomes a failure are never reached. how do software vulnerabilities fit into this scheme of faults and failures? is every fault a vulnerability? is every vulnerability a fault?

When making changes to optimize part of a processor, it is often the case that speeding up one type of instruction comes at the cost of slowing down something else. for example, if we put in a complicated fast floating-point unit, that takes space, and something might have to be moved farther away from the middle to accommodate it, adding an extra cycle in delay to reach that unit. the basic amdahl's law equation does not take into account this trade-off. a. if the new fast floating-point unit speeds up floating-point operations by, on average, 2ă—, and floating-point operations take 20% of the original program's execution time, what is the overall speedup (ignoring the penalty to any other instructions)? b. now assume that speeding up the floating-point unit slowed down data cache accesses, resulting in a 1.5ă— slowdown (or 2/3 speedup). data cache accesses consume 10% of the execution time. what is the overall speedup now? c. after implementing the new floating-point operations, what percentage of execution time is spent on floating-point operations? what percentage is spent on data cache accesses?

Anul 2017 tocmai s-a încheiat, suntem trişti deoarece era număr prim, însă avem şi o veste bună, anul 2018 este produs de două numere prime, 2 şi 1009. dorel, un adevărat colecţionar de numere prime, şi-a pus întrebarea: “câte numere dintr-un interval [a, b] se pot scrie ca produs de două numere prime? “.

Peter is thinking of a number which isless than 50. the number has 9 factors. when he adds 4 to the number, itbecomes a multiple of 5. what is thenumber he is thinking of ?