CISC 3140 - FINAL REVIEW (RED
TEXT)QUESIONS &
ANSWERS(RATED A+)
What are two actions that people involved in the Therac debacle could have taken to
reduce the damage that the machine caused? - ANSWER1. Listen to and investigate
the end-user complaints.
2. Test software successively and refine the old code, instead of relying on old code.
Choose an error in the Therac software and state two actions that people involved in
the Therac debacle could have taken to prevent or reduce the damage that the
machine caused. - ANSWER-Due to concurrent programming errors, the high power
electron beam was activated instead of the low power electron beam, giving patients
approximately 100 times the intended dose of radiation, and resulting in deaths.
-Listen to and investigate the end-user complaints.
-Test for bugs.
-Test software successively and refine the old code, instead of relying on old code.
Why is the Therac report of great importance to programmers (i.e., what is the most
important single fact demonstrated by the report that should be of major importance
to the
approach that should be taken when software is developed)? - ANSWERBad
software kills people.
In what country was the Therac-25 manufactured? - ANSWERCanada
What was one government agency that was involved with dealing with Therac-25
problems? - ANSWERUnited States Food and Drug Administration or Health
Protection Branch of the Canadian
government.
What kind of machine was the Therac-25 (i.e., what was the machine used for)? -
ANSWERAn X-ray and radiation therapy machine used to treat cancer patients.
The Therac report noted several failures in the way error reports for the machine
were handled. What was one such failure? - ANSWERThe machine responded with
an error message after a radiation dose, which usually meant that the treatment was
, not delivered. Due to this unclear and vague error message, the technician
repeatedly delivered beams of radiation to a patient which exceeded safe levels.
What was one error in the Therac software that resulted in a death? - ANSWERDue
to concurrent programming errors, the high power electron beam was activated
instead of the low power electron beam, giving patients approximately 100 times the
intended dose of radiation, and resulting in deaths.
The Therac programmers engaged in several practices that either failed to prevent
errors
from being included in production code or failed to repair programming errors when
incorrect program behavior was detected. Briefly state what two of those detrimental
practices were. - ANSWER- They did not listen to the end-user complaints.
- They did not properly test the software and failed to prevent errors.
- They denied the errors could exist and failed to repair them.
True or False? Replacement of a hardware lockout in a computer controlled machine
by
software will always result in faulty machine operation - ANSWERFalse. We need to
verify the new hardware is compatible with the software. If the hardware
is compatible, the only limitation is the implementation of the software.
What is the main purpose of the Make program? - ANSWERTo construct large
objects from a collection of smaller objects
What is one thing the make program can be used for besides constructing large
programs
from a collection of smaller components? - ANSWERTo include different versions of
some collections of files in a single collection, and extract
only the ones we want.
While "agile programming" has developed something of a cult following, it has major
disadvantages when applied to large programming projects. State one such
disadvantage. - ANSWERBecause of constantly changing specs, agile programming
is not effective for large ongoing
projects.
Why are "critical paths" in PERT charts important? - ANSWERThe critical path is the
longest path to the finish in the context of a PERT chart. A delay in
the critical path means the entire project is delayed, so it is important to keep track of
them
to make sure the project remains on schedule.
Can there be more than one critical path in a PERT chart. If so, why? - ANSWERNo,
a critical path is the longest possible route to finish the project, so logically there can
only be one of those.
In plain English state what the make program will do when it encounters the following
two
TEXT)QUESIONS &
ANSWERS(RATED A+)
What are two actions that people involved in the Therac debacle could have taken to
reduce the damage that the machine caused? - ANSWER1. Listen to and investigate
the end-user complaints.
2. Test software successively and refine the old code, instead of relying on old code.
Choose an error in the Therac software and state two actions that people involved in
the Therac debacle could have taken to prevent or reduce the damage that the
machine caused. - ANSWER-Due to concurrent programming errors, the high power
electron beam was activated instead of the low power electron beam, giving patients
approximately 100 times the intended dose of radiation, and resulting in deaths.
-Listen to and investigate the end-user complaints.
-Test for bugs.
-Test software successively and refine the old code, instead of relying on old code.
Why is the Therac report of great importance to programmers (i.e., what is the most
important single fact demonstrated by the report that should be of major importance
to the
approach that should be taken when software is developed)? - ANSWERBad
software kills people.
In what country was the Therac-25 manufactured? - ANSWERCanada
What was one government agency that was involved with dealing with Therac-25
problems? - ANSWERUnited States Food and Drug Administration or Health
Protection Branch of the Canadian
government.
What kind of machine was the Therac-25 (i.e., what was the machine used for)? -
ANSWERAn X-ray and radiation therapy machine used to treat cancer patients.
The Therac report noted several failures in the way error reports for the machine
were handled. What was one such failure? - ANSWERThe machine responded with
an error message after a radiation dose, which usually meant that the treatment was
, not delivered. Due to this unclear and vague error message, the technician
repeatedly delivered beams of radiation to a patient which exceeded safe levels.
What was one error in the Therac software that resulted in a death? - ANSWERDue
to concurrent programming errors, the high power electron beam was activated
instead of the low power electron beam, giving patients approximately 100 times the
intended dose of radiation, and resulting in deaths.
The Therac programmers engaged in several practices that either failed to prevent
errors
from being included in production code or failed to repair programming errors when
incorrect program behavior was detected. Briefly state what two of those detrimental
practices were. - ANSWER- They did not listen to the end-user complaints.
- They did not properly test the software and failed to prevent errors.
- They denied the errors could exist and failed to repair them.
True or False? Replacement of a hardware lockout in a computer controlled machine
by
software will always result in faulty machine operation - ANSWERFalse. We need to
verify the new hardware is compatible with the software. If the hardware
is compatible, the only limitation is the implementation of the software.
What is the main purpose of the Make program? - ANSWERTo construct large
objects from a collection of smaller objects
What is one thing the make program can be used for besides constructing large
programs
from a collection of smaller components? - ANSWERTo include different versions of
some collections of files in a single collection, and extract
only the ones we want.
While "agile programming" has developed something of a cult following, it has major
disadvantages when applied to large programming projects. State one such
disadvantage. - ANSWERBecause of constantly changing specs, agile programming
is not effective for large ongoing
projects.
Why are "critical paths" in PERT charts important? - ANSWERThe critical path is the
longest path to the finish in the context of a PERT chart. A delay in
the critical path means the entire project is delayed, so it is important to keep track of
them
to make sure the project remains on schedule.
Can there be more than one critical path in a PERT chart. If so, why? - ANSWERNo,
a critical path is the longest possible route to finish the project, so logically there can
only be one of those.
In plain English state what the make program will do when it encounters the following
two
