Ex. 1 Input/Output

1. Is it possible to scan a document and send it through a wireless network at full speed? Explain why, why not.
2. How can an OS facilitate the installation of a new device without any need to recompile the OS or even to reboot it?
3. In the slides four I/O software layers are listed; in which layers are the following operations done:
   1. Computing the track, sector, and head for a disk read
   2. Writing command to the device registers
   3. Checking is the user is allowed to use the device
   4. Converting binary integers to ASCII for printing
4. A DMA controller has four channels. The controller is able to request a 32bit word every 100 nsec.

A respond takes equally long. How fats should the bus be in order to avoid being a bottleneck?

5. Briefly explain what a thin client is.
6. Describe how a hard disk is working and give a few details regarding its geometry.
7. What are differences between RAID 0, 1, 5, 6, and 10?

Ex. 2 Multiprocessors

1. Suppose that the TSL instruction was not available for synchronizing a multiprocessor. Instead, another instruction, SWP was provided that atomically swapped the contents of a register with a word in memory. How could that be used to provide multiprocessor synchronisation?
2. Briefly describe virtualization and the main challenges that need to be overcome.

Ex. 3 File systems

1. Assuming the current working directory is /usr/share/doc/mutt/examples what is the absolute path of ../../../doc/../../lib/mutt?
2. A Unix system has 1KB blocks and 4B disk addresses. What is the maximum file size if i-nodes contain 13 direct entries, and one single, double , and triple indirect entry each?
3. The time required to read a certain number of bytes can be approximated by summing the seek, rotation delay, and transfer times. Given a disk with mean seek time of 8 msec, a rotation rate of 15,000 rpm and 262,144 bytes per track what are the data rates for block sizes of (i) 1 KB, (ii) 2 KB, and (iii) 4 KB?

Ex. 4 Security

1. If using only lowercase letters how many possible 8 letter words can be chosen? Explain why a password should always contain lower and uppercase letters, numbers and symbols.
2. Explain why memory dynamically allocated using malloc is sometimes random and some other times set to 0.
3. A computer system is made of several components each featuring a different level of security.

How secure is this system?

4. Can security be achieved? Explain your answer.

Ex. 5 Research

Write about a page on the topic of firewalls on Linux systems; include information on iptables, ebtables, and arptables. Do not forget to reference your sources of information.

Ex. 6 Linux

What is a kernel panic? Generate one on your Linux system and troubleshoot it. Provide all the details.

Ex. 7 Course survey

Complete the course evaluation survey and get a +5 bonus on the homework.v