The reliability of a hard-disk drive is typically described in terms of a quantity called mean time between failures (mtbf). although this quantity is called a "time," the mtbf actually is measured in drive-hours per failure. if a system contains 2000 drives, each of which has a 850,000-hour mtbf, how often a drive failure will occur in that disk farm per year?

In which phase does software coding and testing happen in the spiral model? the spiral model does not have a separate testing phase. both, software coding and testing occurs during the phase.

Working on this program in python 3.7: a year in the modern gregorian calendar consists of 365 days. in reality, the earth takes longer to rotate around the sun. to account for the difference in time, every 4 years, a leap year takes place. a leap year is when a year has 366 days: an extra day, february 29th. the requirements for a given year to be a leap year are: 1) the year must be divisible by 42) if the year is a century year (1700, 1800, the year must be evenly divisible by 400some example leap years are 1600, 1712, and 2016.write a program that takes in a year and determines whether that year is a leap year.ex: if the input is 1712, the output is: 1712 is a leap year. ex: if the input is 1913, the output is: 1913 is not a leap year. your program must define and call the function isleapyear(useryear). the function should return true if the input year is a leap year and false otherwise.

Evaluate the scenario below and indicate how to handle the matter appropriately. situation: michael received an e-mail from what he thought was his doctor’s office, requesting his social security number. since he had just been in to see his doctor last week, he replied to the e-mail with his social security number.