CIS-2151 Lab Assignment #1: Introduction

Reading: Chapter 1 in the text is a broad overview of the subject. I recommend skimming it to see what's there, maybe reading a bit if you see something that interests you. We will start the main content of the course with Chapter 2, especially sections 2.1 through 2.4. Start looking at those sections when you can, but we won't be getting into that material in detail until next week.

The primary purpose of this lab assignment is for you to get connected to Lemuria. You will also do some practice with number systems.

Part 1

You should have received your Lemuria credentials in email (subject line "Lemuria Credentials"). Install an SSH client on your system, such as PuTTY, and use it to connect to Lemuria. Mac users might be interested in these notes for using SSH on a Mac.
Create a small text file (on Lemuria) using a text editor such as nano. For example, create a file named myfile.txt using the command:
```
      $ nano myfile.txt
    
```
The nano editor is easy to use. Just type. At the bottom of the screen you will see a list of commands that you can activate. The '^' character before a letter means that you must use the Ctrl key with that letter. For example, "^X" means type "Ctrl+X". This exits nano, but you will be prompted to save the file first.

Try out some Linux commands: ls, cp, rm, and mv. For example (the text after '#' is a comment; don't type that text):

      $ cp myfile.txt myfile-backup.txt   # Make a backup copy.
      $ rm myfile.txt                     # Delete the original.
      $ mv myfile-backup.txt myfile.txt   # Move (rename) the backup to the original name.

Use the ls command after each command above to see what is happening to your files.

On your personal system install a file transfer program such as WinSCP. Use it to transfer your text file from Lemuria to your personal system. This is how you can later back up your work.
Try running the command:
```
      $ tshark -i em1
    
```
You will need to type ^C (that's Ctrl+C) to end the output. The tshark command is a network analyzer. It allows you to see all the traffic going to/from a particular network interface. In this case you are looking at the interface named "em1" which is connected to the VTC local area network (LAN). Each frame is represented by one line in this summarizing view. We will be making extensive use of this tool to observe and dissect network traffic.

Note that using a tool like tshark on the VTC LAN is a violation of Policy 502. Such tools potentially allow you to see the network traffic generated by other users, and give you access to the data those other users are downloading or uploading. This creates privacy concerns and also allows you, potentially, to see sensitive, confidential information. However, Lemuria is connected to a CIS lab network which has an exemption to Policy 502 for educational purposes.
(OPTIONAL) Tshark is a powerful tool with many features. If you feel like exploring more, I invite you to try the commands on my Tshark quick-start page. We will do all the things described on that page, and more, in future labs, so it is not necessary to do it right now.
(OPTIONAL) There is a text-mode mail program on Lemuria called alpine. To start it use the command:
```
      $ alpine
    
```
You can use the arrow keys to navigate around the display. You can also type individual letters or control characters to activate commands (alpine's interface is similar to nano's). Go into the "Setup" menu and select "C" to configure alpine. Set your "Personal Name" (at the top of the list of configurable items), and set the "User Domain" to "lemuria.cis.vtc.edu". Exit from the setup screen, and compose an email to yourself with the file you created earlier as an attachment. This is an alternate way to transfer files off Lemuria.

You may have to use your VTC email address as the recipient address. The email system on Lemuria is not completely configured; major email providers such as Google may reject email sent from it as potential spam. Also, there is currently no way to receive email on Lemuria, so you won't be able to reply to the messages you receive from the system. It is possible that email might work better on Lemuria at some future time.

Part 2

In this part you will get some practice with number conversions. For the questions, below show your work using the methods described in class. That way I can check that you understand the concepts. You can, however, check your work using an online conversion tool.

Convert the following values to 8-bit binary numbers (by specifying the size, I mean you should include leading zeros when necessary to make the result 8 bits). For each binary value, also show a two-digit hex representation (again, with a leading zeros, if necessary). You should be able to just write down the hex representation directly from the binary value.
- 127
- 65
- 192
- 224
Convert the following values directly to 16-bit hex numbers (with leading zeros, etc.) using the same approach as presented in class. For each hex value, also show a 16-bit binary representation (with leading zeros, etc.). You should be able to just write down the binary representation directly from the hex value.
- 65535
- 4096
- 256
- 1
Convert the string "CIS-2151 is fun." to a sequence of ASCII values represented as two-digit hex numbers. Be sure to note the difference between upper and lower case letters, and don't forget to show the ASCII values for the dash, the space, and the period at the end. For this question, I'm expecting you to just look up the answer in an ASCII table.

Submit a document to Canvas with your answers for Part 2. You do not need to submit anything for Part 1 in this lab. I prefer submissions to be in PDF format, but I will accept plain text, MS Word, or OpenDocument Text (LibreOffice or OpenOffice). If you want to use some other format, contact me first.