Black box testing, also called functional testing and behavioral testing, focuses on
determining whether or not a program does what it is supposed to do based on its
functional requirements. Black box testing attempts to find errors in the external
behavior of the code in the following categories:
(1) incorrect or missing
(2) interface errors
(3) errors in data structures used by interfaces
(4)behavior or performance errors
(5) initialization and termination errors. Through
this testing, we can determine if the functions appear to work according to specifications.
However, it is important to note that no amount of testing can unequivocally demonstrate
the absence of errors and defects in your code.
On a somewhat unrelated note, is there a specific name for the way Jane Austen wrote or the narrative techniques she used? I’m thinking of the way she can be very vague about details when information is irrelevant (kind of like your Treasure Island example when the specific year is omitted, “in the year of grace 17–-“)… Also, the way she will put the gist of what someone says in conversation in one giant paragraph-long quote without using first-person pronouns.
For example, from Sense and Sensibility:
Sir John could not have thought it possible. “A man of whom he had always had such reason to think well! Such a good-natured fellow! He did not believe there was a bolder rider in England! It was an unaccountable business. He wished him at the devil with all his heart. He would not speak another word to him, meet him where he might, for all the world! No, not if it were to be by the side of Barton covert, and they were kept waiting for two hours together. Such a scoundrel of a fellow! such a deceitful dog! It was only the last time they met that he had offered him one of Folly’s puppies! and this was the end of it!”
There are drawbacks to multi-factor authentication that are keeping many approaches from becoming widespread. Some consumers have difficulty keeping track of a hardware token or USB plug. Many consumers do not have the technical skills needed to install a client-side software certificate by themselves. Generally, multi-factor solutions require additional investment for implementation and costs for maintenance. Most hardware token-based systems are proprietary and some vendors charge an annual fee per user. Deployment of hardware tokens is logistically challenging. Hardware tokens may get damaged or lost and issuance of tokens in large industries such as banking or even within large enterprises needs to be managed. In addition to deployment costs, multi-factor authentication often carries significant additional support costs. A 2008 survey  of over 120 . credit unions by the Credit Union Journal reported on the support costs associated with two-factor authentication. In their report, software certificates and software toolbar approaches were reported to have the highest support costs.