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(comp355)[2008](s)quiz1-sol~PPSpider^_10208.pdf
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COMP 355 Embedded Systems Software
Spring Semester 2008
Quiz 1
Date: 17 Feb. 2008 Time: 9:00 am - 9:20 am (20 minutes)
Name:_____________________ Student ID: ________________Email:____________________
Instructions
1. Please write your name, student ID and email address on this page.

2. Please answer all the questions within the space provided on the examination paper. Use no more than two or three sentences each.

3. This quiz consists of 6 questions and is printed on both sides of the sheet.


Questions (Answer in one or two sentences each.)
1. (2 points) Give one important difference between standard computer systems and real-time systems.



Key words: deadline constraint




2. (2 points) Give one difference between hard real-time systems and soft real-time systems.




Hard Real-time systems: Deadline violation/miss catastrophic.

Soft Real-time systems: Occasional Deadline violation/miss acceptable.


3. (2 points) Do you think a linker/locator in embedded software development needs to do address resolution? Explain your answer in one sentence.



Yes. Even for linker/locator, the address resolution step is needed to fix up references to variables and external references including to external variables, functions and library calls.




4. (3 points) Does a cross-compiler always need to generate object code for a CPU whose instruction set is different from the host computers CPU instruction set?



No, (1 pt) whether it is a native compiler or a cross-compiler, it generates code for a target processor (1pt). There is no restriction that the target processor instruction set needs to be different from the host processor instruction set. (1 pt)







5. (3 points) Can the linker use the same libraries that are used on the host workstation while generating the executable code for the target?




No (1 pt). The libraries should be especially compiled for the target processor (2pts).








6. (3 points) Why do you think real-time embedded systems do not use virtual memory?




The use of virtual memory cannot provide guarantees on the access time to memory locations. Consequently, the execution time of instructions cannot be guaranteed.