CS514 Operating Systems
Spring 2009
List of the Questions for Chapter 1
The following list contains questions that summarize the foundation of computer architecture
and organization that are essential for understanding operating systems. The test next week
will ask some of the following questions. However, at least two or three questions that do not
appear in the following list will still appear in the summary quiz.
The following sections are NOT included:


Section 1.3 (Instruction Execution): page 13-16
Paragraphs for “Multiple Interrupts” in Section 1.4: page 23-26
#1: What are the four primary components (elements) in a computer (as hardware components)?
Proc mem, io, system bus
#2: What can the content in a memory be for a processor?
Instructions, data?
#3: What are two different groups of registers in a processor?
User visible and control/status
#4: What are two groups of registers in “user-visible registers”?
Data, address
#5: Mention three examples of address registers.
Index, segment, stack pointer
#6: Which group of registers are also known as “GPR’s”?
User-visible registers
#7: Which register is unique to the processors that implement segmentation (the register that
will not exist in the processors that do not implement segmentation)?
Segment pointer
#8: Examples for the stack pointer
#9: Mention three examples of the control and status register.
Program counter, instruction register, condition code(flags)
#10: Mention at least two flags in the flag (status) register. For each of the two flags you
mentioned, briefly explain how it is used in assembly programs.
Overflow, ?
#11: Which flag in the flag (status) register is used to terminate a loop structure with a certain
number of iterations?
Zero flag?
#12: Briefly (within 40 words, using your words) explain why interrupt can improve
efficiency?
#13: Is the following statement TRUE or FALSE?
“Interrupt can interrupt a processor while it is in the middle of executing an instruction”.
false
#14: What is “interrupt handler”?
Determines what i/o module generated the interrupt and branch to program associated with
intterrupt
#15: What contains an interrupt handler (select the most appropriate option from the list
below)?
(a) User application program
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(b) Operating system bug patches
(c) Device driver
(d) User application updates
(e) None of the above
(f) All of (a) through (d)
all
#16: As a part of interrupt handling, on an interrupt a processor switches from a currently
executed process to an interrupt handler and the contents of the registers will be saved.
How is this sequence of activities called?
Interrupt processing
#17: What are the three primary performance metrics for memory?
How big, how fast, how expensive
#18: What are the typical trade-off problems in memory subsystem in computers?
Faster->more expensive/bit, bigger->cheaper/bit, bigger->slower
#19: What is “memory hierarchy”?
#20: Why is the memory subsystems for most of the computer systems is designed using
memory hierarchy?
Gets close to faster access time
#21: What is “locality of references” in memory?
Memory references tend to cluster
#22: Why is “locality of references” an important concept?
It allows memory heirachy to work
#23: In the future, it could be that the concept of “locality of references” may not be an
important concept any more, but how?
If everything can be put in registers, or main memory becomes as fast as registers
#24: What is “secondary memory” (answer this question as a concept not by providing
examples)? Explain the concept using your words (up to 8 words).
External non-volitale memory
#25: What is the primary motivation of using cache memory?
#26: What is “word transfer”? Where is “word transfer” used?
usually determined in a computer system?
Cache->cpu, size of data
How is the “word size”
#27: What is “block transfer”? Where is “word transfer” used?
usually determined in a computer system?
Cache->main memory
#28: What is the advantage of using block transfer?
How is the “word size”
#29: What are the primary design factors for cache memory?
examples.
Cache size
Block size
Mapping function
Replacement algo
Write policy
#30: What if:

If the block size is relatively too small?
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For each factor, mention

If the block size is relatively too large?
#31: How (or “when”) is programmed I/O used?
#32: How (or “when”) is programmed I/O used?
#33: What program does “program” in “programmed I/O” mean (mention the name of the
program)?
#34: What are the primary differences between “programmed I/O” and “interrupt-driven I/O”?
#35: For which of “programmed I/O” or “interrupt-driven I/O”, their response time is more
important? Briefly explain why.
#36: What problem(s) could occur if a computer system does not use “interrupt-driven I/O”?
#37: Why was DMA introduced? Explain the primary reason using your words.
Take load off of proc
#38: Describe the typical DMA procedure (for data transfer from memory to an I/O device).
You can assume the DMA is the one available in the computer system (not in an I/O
device).
#39: What are the typical parameters a processor needs to provide to a DMA controller (for
data transfer from memory to an I/O device). You can assume the DMA is the one
available in the computer system (not in an I/O device).
Read/write,address of i/o, mem location, size
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Notes:
(1) You can prepare your solutions for the above questions using group-study method and share
the solutions except for those questions that are specified as “answer the question using
your words”. For those questions, you must provide a solution using your words (i.e. you
can NOT share a solution with your classmate).
(2) Since the questions contained in the above list are all from undergraduate computer
architecture and organization, everyone should not have a serious problem in preparing a
solution. Therefore, Dr. Fujinoki will not provide solutions for the list before the test.
For anyone who has serious problems in preparing solutions for the above list, it is strongly
recommended for you to take CS516 (Computer Architecture) before you take this course.
(3) Since the test for the above questions is a part of the first midterm exam, serious academic
dishonesty will result in zero credit for your first midterm exam. If there is anything
unclear for the SIUE standards for academic dishonesty, please talk to Dr. Fujinoki for his
advises. Dr. Fujinoki will NOT be responsible for your wrong assumptions for the criteria
for academic dishonesty.
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