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?

Your task this week is to write a very simple spam classifier in python. it will classify messages as either spam (unwanted) or ham (wanted). the program will have a set of spam_words, words that are known to appear in spam messages. that set is included in the template file spam.pypreview the document. you will also define a spam threshold which reflects the allowed percentage of spam words in the message. you'll compute a 'spam indicator', which is the ratio of spam words to the total number of unique words in the message. if the spam indicator exceeds the spam threshold, the message is classified as spam. otherwise it is classified as ham. we'll assume that the spam threshold is a constant and has a value of 0.10. your program will prompt the user for a message and then will print the corresponding spam indicator with two decimal digits and the corresponding classification (spam or ham). the program will be case insensitive. the spam words are detected whether they are in lower case or upper case or mixed case. each word, spam or not, is counted once (even if it appears multiple times in the message.) the program will remove punctuation from the message before identifying the words and computing the spam indicator. for example '! ' must be identified as the spam word 'now'.

Explain why it is reasonable to assume that receiving 3 duplicate acks in tcp is an indication that the network is not currently congested.

Alook-up table used to convert pixel values to output values on a monitor. essentially, all pixels with a value of 190 or above are shown as white (i.e. 255), and all values with a value of 63 or less are shown as black (i.e. 0). in between the pixels are scaled so that a pixel with a value p is converted to a pixel of value 2/127 −+3969). if a pixel has a value of 170 originally, what value will be used to display the pixel on the monitor? if a value of 110 is used to display the pixel on the monitor, what was the original value of the pixel?