Betriebssysteme/hw3/simu1/QUESTIONS.md

Questions 15-Relocation

The program relocation.py allows you to see how address translations are performed in a system with base and bounds registers. See the README for details.

Warmup

Run with seeds 1, 2, and 3, and compute whether each virtual address generated by the process is in or out of bounds. If in bounds, compute the translation.

Please answer the questions, by giving the result and - if asked - an explanation, why you got the result. Write your answers in markdown syntax in the new file ANSWERS.md.

Questions

1. Run with these flags: -s 0 -n 10. What value do you have set -l (the bounds register) to in order to ensure that all the generated virtual addresses are within bounds?

2. Run with these flags: -s 1 -n 10 -l 100. What is the maximum value that base can be set to, such that the address space still fits into physical memory in its entirety (explanation)?

3. Run some of the same problems above, but with larger address spaces (-a) and physical memories (-p). How does increasing effect the results (explanation)?

4. For each virtual address, either write down the physical address it translates to OR write down that it is an out-of-bounds address (a segmentation violation). For this problem, you should assume a simple virtual address space of a given size.

```text ARG phys mem size 16k

Base-and-Bounds register information:

 Base   : 0x00003952 (decimal 14674)
 Limit  : 1024

Virtual Address Trace

 VA  0: 0x0000024c (decimal:  588) --> PA or segmentation violation?
 VA  1: 0x000004eb (decimal: 1259) --> PA or segmentation violation?
 VA  2: 0x000002bd (decimal:  701) --> PA or segmentation violation?
 VA  3: 0x000000fa (decimal:  250) --> PA or segmentation violation?
 VA  4: 0x00000486 (decimal: 1158) --> PA or segmentation violation?
 VA  5: 0x00000521 (decimal: 1313) --> PA or segmentation violation?
 VA  6: 0x0000065c (decimal: 1628) --> PA or segmentation violation?
 VA  7: 0x000001a3 (decimal:  419) --> PA or segmentation violation?
 VA  8: 0x0000063a (decimal: 1594) --> PA or segmentation violation?
 VA  9: 0x0000034d (decimal:  845) --> PA or segmentation violation?
```