Pre-class Activity 11: Disk Performance

FInd out the make and model of the hard disks you owned and used, both internal and external.  Go to the manufacturer websites and find out the specification — what is the average rotational time, seek time, and transfer time to read a block of data of your disks?   Which component is dominating the disk access time?

Pre-class Activity 9

Try running some memory-intensive programs (e.g., Adobe software, Firefox) and observe some information related to page faults on your computer:

1. For Windows users, open Task Manager, go to “View”, “Select Columns”, and show the “Page Fault” and “Page Fault Delta” columns. Observe the number of page faults for each process and how many new page faults are generated between updates (the delta).

2. For Linux users, open up a terminal and run “vmstat k”, where k is an integer that indicates the update interval. (man vmstat for details). Observe the “si” and “so” columns, which reports on the amount of memory swapped in and swapped out. Alternatively, run “ps -ea v” and observe the “MAJFL” columns, which report on the number of page faults.

3. For Mac users, open up a terminal and run “vm_stat k”, where k is an integer that indicates the update interval (man vm_stat for details). Observe the numbers under columns “faults”, “pageins” “pageouts”.

For comparisons with your friends, post the amount of RAM on the system you are making the observations on.

Pre-class Activity 8

1. On Windows, launch Task Manager. Under the Process tab, observe the amount of memory used by the processes. You can go to “View” and “Select Columns”. There are many different columns that corresponds to different accounting of memory usage. What are they? Can you identify some processes that hog the memory in your system?

2. On Linux or Mac, run top. Similarly, you can display various information related to memory usage of processes on your system. What are they? Can you identify some processes that hog the memory in your system?

Pre-class Activity 6

If you are running Windows, run the Task Manager, then go to “View”, “Show Columns..”, and enable the column “Base Priority.” (Detail could be different for different Windows version).

If you are running Linux or Mac OS X, invoke the shell and run ps -Ao user,args,pri. The last column shows the priority of each processes. Pipe it through less if the output is too long to see in one screen.

  1. What are the different priority levels you observe? What are some processes that have higher priority?
  2. When you run a multimedia programs (audio conferencing, video player), observe the priority of the processes associated with these programs.

Pre-class Activity 2

Perform the following on either MS Windows, Mac OS X, or Linux:

  • MS Windows: Type Ctrl-Shift-Esc to bring up the Task Manager and choose the tab “Applications” and “Processes”
  • Mac OS X: Run Activity Monitor (found under Applications / Utilities) and choose the tab “CPU”.
  • Linux: Open the terminal and type ps -eaf.

What do you see? What are the attributes shown? What do they mean? Explore the options/preferences/command line arguments for the respective tools you used.

Pre-class Activity 1

I try to post some pre-class activities every week before the lecture. These are activities that you can do or think about before each lecture. We may not explicitly discuss every pre-class activity during lecture and tutorial, but nonetheless following each activity could help improve your understanding of the class. Feel free to discuss these activities online (via commenting on this blog post) with your classmates and the teaching staff.

What is an operating system?

  1. Google “define: operating system” and see what the rest of the Web say.
  2. Microsoft tried to bundle the Internet Explorer with every Microsoft Windows, claiming that it is part of the operating system (see Wikipedia entry on US vs MSFT)

    Based on your understanding what an operating system is, should the Web browser be part of the operating system?

  3. Recently, a new phrase “The Web browser is the new operating system” has emerged. What does this mean? Do you agree?