CIS 505: Software Systems

Transcription

1 CIS 505: Software Systems Fall 2018 Assignment 0: Using the Virtual Machine Image Due September 7, 2018, at 10:00pm EDT 1 Background We will be offering a standardized development system for CIS 505 that is based on a virtual machine image. This image contains a small Linux installation and all the tools you will need for the homework assignments. Having such a standardized system has several advantages: 1. You do not have to worry about incompatibilities between the software we will be using and other software that may be installed on your machine; 2. If something goes wrong, you have a 'safe' configuration to go back to just reinstall the virtual machine image; 3. The virtual machine image will be the 'gold standard' for grading; thus, if your solution works in the VM image, you can be sure that it will also work on the graders' machines. The virtual machine image works with VMware Workstation, which has been installed on the Linux and Windows machines, such as M100A, M204 (Ketterer Lab), and Towne-M70. If you prefer using your own computer, you should be able to get a free copy of VMware Workstation for Windows or VMware Fusion for macos ( If you are a Linux user, try VirtualBox ( Of course, you are free to use a different development system (e.g., a different operating system, your favorite editor or IDE,...). However, we will only grade solutions based on their performance in the virtual machine image, and we can only offer limited support if you decide to use your own setup. 2 Installing the VM image Your first task is to install the VM image for this assignment. If you are using VMware Workstation (e.g., in one of the labs): 1. Download the VM image from 2. Unpack the.zip file; this should produce a folder called cis Start VMware Player (if you are using a Linux machine in the lab, press Alt+F2 to open the 'Run' dialog and enter vmware; you can also open a terminal and run vmware from there) 4. Click File -> Open. In the dialog box that appears, open the cis505 folder, select the CIS505.vmx machine image, and click 'Open'. 5. Click 'Play virtual machine'. If it asks whether the VM was moved or copied, say 'I moved it'.

2 If you are using VirtualBox: 1. Download the VM image from 2. Unpack the.zip file; this should produce a folder called cis Start VirtualBox and click New. For name, enter CIS505. Set the type to Linux and the Version to Ubuntu (64 bit). Click Continue and set memory to 2048 MB. (For Linux users, you might need to disable Secure Boot in the BIOS settings for VirtualBox to run.) 4. Check Use an existing virtual hard drive file. Open the cis505 folder and select Virtual Disk.vmdk. Click Create. (If you get a "Failed to open disk image" error, we recommend that you try the slightly older version 4.3 of Virtual Box, which you can download from 5. Click Start. If you are using VMware Fusion: 1. Download the VM image from 2. Unpack the.zip file; this should produce a folder called cis Rename this folder to CIS505.vmwarevm 4. Double-click on the folder in Finder; the VM should open directly. Whether you are using Workstation, Fusion, or VirtualBox, the Linux in the VM image should boot now. Wait until the login dialog appears. Click on 'CIS505' to log in. The password is vm. 2.1 A few tips regarding the virtual machine If you run out of storage space while unpacking vm.zip, try downloading vm.zip to a temporary directory (e.g., /tmp), and then unpack it to your home directory from there. (Do not unpack the VM image to /tmp, since files in this directory are deleted regularly!) CETS has allocated some extra space for CIS505 students; if you have a SEAS account, you should already have a symbolic link called cis505-vm in your home directory that points to this space. (If you don't have a SEAS account yet, go to this page contains instructions for requesting an account.) If the VM image doesn't fit into your normal SEAS account, please store it in this space. Always (!) shut down the VM properly before closing VMware Player (by clicking on the power button icon the lower right corner and selecting 'Shutdown'). If you do not do this, the VM image can become corrupted, just like your operating system can become corrupted if you switch off your computer before shutting it down properly. In particular, do not just 'power off' the virtual machine using the command in VMware Player, and do not just close VMware Player altogether. Always hit the button that is highlighted in the screenshot on the right, and wait for the VM to power off on its own. If the screen size of your VM is tiny, try resizing it or putting it into full-screen mode. If this doesn't do anything, you may need to reinstall the Guest Additions for your particular VMM.

3 For instance, if you are using VirtualBox, you can do this by opening a terminal (by clicking on the LXTerminal icon on the desktop) and running the following command: cis505@vm:~$ sudo apt-get install virtualbox-guest-additions-iso You will be prompted for the root password; please enter "vm". The VM will then download a few things, and then ask you whether to continue the installation; press Y to continue. (If the installation fails, try installing linux-kernel-headers and virtualbox-guest-dkms before installing the Guest Additions; you can do this by running sudo apt-get install linux-kernel-headers and sudo apt-get install virtualbox-guestdkms in the terminal window.) Once this is done, continue with the following commands to complete the installation: cis505@vm:~$ sudo mkdir /media/iso cis505@vm:~$ sudo mount /usr/share/virtualbox/vboxguestadditions.iso /media/iso cis505@vm:~$ sudo /media/iso/vboxlinuxadditions.run After the installation completes, reboot the VM as shown above (do not simply close VirtualBox!!). Once the VM has rebooted, you should be able to resize it. Note that the mouse pointer has to be over the VM window; otherwise your inputs will not be accepted. If at any point your mouse or keyboard are 'captured' by the VM (i.e., you can no longer move the mouse outside of the VM window or switch to other applications), press the 'Ctrl' and 'Alt' keys simultaneously (or Right Ctrl in VirtualBox). This should also help you to get out of 'fullscreen mode'. The data you store inside the VM is persistent (i.e., will survive reboots), and we will be using a version control system; nevertheless, we strongly recommend that you make occasional backups, e.g., by copying your data to eniac.seas.upenn.edu using the scp command. The password for the cis505 user is vm. You shouldn't normally need to become root, but if this ever becomes necessary, you can use sudo with the same password. If you would like to use a text editor other than Eclipse, please use apt-get to install it. For instance, to install gedit, run sudo apt-get install gedit in a terminal window. If the virtual disk (the.vmdk file(s) in the cis505 folder) is getting too big, try deleting some files inside the VM and then 'compacting' it (under Virtual Machine Settings... / Hard Disk (SCSI) / Utilities / Compact). This should free up some space on the host machine. You should be able to view and modify the number of CPUs of the VM in the setting of your VM Player; this option is useful for the latter homework assignments (such as HW1). For instance, if you use VirtualBox, you can view/modify the number of CPUs by going to Setting à System à Processor, and then selecting the desirable number of processors. Note that modification is only allowed when the VM is not running. If you want to set up a shared folder between your VM and your own machine to easily access files in your VM when you re outside the VM, you can set up a shared folder as follows:

4 If you are using VirtualBox: If you haven't already, install the Guest Additions as described above. Open VirtualBox, select your OS on the left then click on Shared Folders on the right. Click on the green cross on the top right to add a new Shared Folder Fill out the form by selecting which folder you want to share between your machines. Check auto mount and Save. Start up your Ubuntu now and navigate to /media and you will see your shared folder as sf_foldername. However, if you try and open it you ll get a permissions error. In order to access it from inside the vm, you need to open Terminal and paste in the following command: sudo usermod -a -G vboxsf cis505 (you'll need to reboot the VM after this!) If you should get an error message (e.g., "usermod: group 'vboxsf' does not exist"), try reinstalling the VirtualBox Guest Additions. Some virtual machine monitors also allow you to copy and paste texts from your host OS to the VM, and vice versa. To make this work, you may need to enable the corresponding feature; for instance, in VirtualBox it is called Shared Clipboard, and you can switch it on with the "Devices" / "Shared Clipboard" / Bidirectional" command from the VM window. 2.2 Configuring the VM Next, you need to configure the VM. To do this, open the Firefox browser in the VM (by double-clicking on the Firefox icon on the deskrop) and then enter the following URL: The web page will ask you to log in with your PennKey credentials. Once you have done this, Firefox will automatically download a file to your VM and pop up a window to ask you what to do with it. Select "Save File", and download the file to the "Downloads" folder. Now close Firefox and open a terminal (LXTerminal icon on the desktop). Enter the following into the window that appears: cis505@vm:~$ chmod 755 Downloads/configure-vm.sh cis505@vm:~$./downloads/configure-vm.sh If all goes well, you should see a message that starts with "Your VM is now configured for..." and that contains your name, SEAS login, and address. If you do not see this message; please check Piazza for solutions. 3 The HelloWorld application [10 points] Your third task in this assignment is to write a simple C program that writes your full name and your SEAS login name to stdout when it is invoked (for example, my own solution writes "*** Author: Linh Thi Xuan Phan (linhphan)"). This is not rocket science. We know. The goal is to familiarize yourself with the VM, and to try out the homework submission process, which is described below. In the following, we will assume that your VM

5 can successfully connect to the network. If you are not sure about the network connection, double-click on the Firefox icon on the desktop; this should open the CIS505 web page. To get started, open a terminal (click on the "LXTerminal" icon on the desktop), and then run the following two commands: rm -rf git git clone ssh://yourseaslogin@cis505.cis.upenn.edu/git/cis505/yourseaslogin/./git but replace the two occurrences of yourseaslogin with your actual SEAS login name. Do not forget the part at the end, and do not add or omit spaces! If you are asked whether you are sure that you want to continue connecting, type yes and hit Enter. You should now see messages like this: Cloning into './git'... remote: Counting objects: 9, done. remote: Compressing objects: 100% (8/8), done. remote: Total 9 (delta 0), reused 0 (delta 0) Receiving objects: 100% (9/9), done. After this, you should have a folder called git in your home directory (you can run ls in the terminal to check). Next, open Eclipse (Eclipse icon is on the desktop) and close the Welcome screen that will appear. Then click on "File..." / "Import..."; expand the "General" item; click on "Existing Projects into Workspace"; and click Next. Hit "Browse...", choose /home/cis505/git, and hit OK. Then check the box next to 'HW0' and hit Finish. You should now see the HW0 project in the Project Explorer on the left. Be sure to enable the C++ perspective - click on "Window" / "Perspective" / "Open Perspective" / "Other..." / "C/C++". Next, find the hello-world.cc file, and add the necessary code to write your full name and SEAS login. Please use the exact format above (Example: "*** Author: Linh Thi Xuan Phan (linhphan)"). Also, open the README file and complete all the fields. Finally, check all your changes back into the repository. To do this, open a terminal again (see above), and then run cis505@vm:~$ cd git/hw0 cis505@vm:~$ git status This should show that several files (hello-world.cc, README) have been modified. To commit your changes and send them back to the server, run cis505@vm:~$ git commit README hello-world.cc -m "Solved HW0" cis505@vm:~$ git push Notice how the commit command is given a list of files to commit, as well as a short descriptive message in upper quotes. You can use this message later to remember what you have changed; if you do not specify a message, an emacs window will open, and you can enter the message there. The push command sends the changes back to the server; if this succeeds, your changes are checked in.

6 For later assignments, we strongly recommend that you regularly check in your changes, at least once a day and/or whenever you've implemented a major new feature. That way, when something suddenly stops working, you can use git's diff feature to find the changes you've made since the last checkin. Also, when you create additional files, please don't forget to add them to the repository. 4 Requesting extensions We strong recommend that you start working on each assignment as soon as it becomes available. That way, if you encounter an unexpected problem that you cannot resolve by yourself, you will have enough time to post a question on Piazza, or to come to office hours. However, we do realize that things do not always go as planned. Therefore, you automatically receive three 'jokers' at the beginning of the semester, which you can redeem for a one-day extension. To redeem a joker, please go to You will see a list of assignments, the corresponding deadlines, and the number of remaining jokers. To spend a joker to extend one of the deadlines, click on "Extend". You can spend all jokers on one assignment, or each joker on a different assignment; however, you cannot extend a deadline that has already passed (it is ok to spend one joker before the original deadline, another one the next day, etc.). Once you have spent your three jokers, you cannot get further extensions for any reason, and each late day will lower your score by 20%. Therefore, we recommend that you try to save your jokers for emergencies and/or the inevitable time crunch at the end of the semester. The best way to save your jokers is to start early. 5 Packaging and submitting your solution Once you are ready to submit, you should first check in all your changes. After that, you should prepare a package with your source code as follows. First, double-click on the Terminal icon on the desktop to open a terminal window. In that window, run the following commands (text you should type is underlined): cis505@vm:~$ cd git/hw0 cis505@vm:~/git/hw0$ make pack rm -f submit-hw0.zip zip -r submit-hw0.zip hello-world.cc README Makefile adding: hello-world.cc (deflated 25%) adding: README (deflated 48%) adding: MAKEFILE (deflated 33%) cis505@vm:~/git/hw0$ This will create a file called submit-hw0.zip, which should automatically include all the source code you have written (to verify, you can run unzip -l submit-hw0.zip). Next, open Firefox and go to the following page:

7 You should see a list of homework assignments, along with the due date for each, as well as a submission form at the bottom of the page. Choose "HW0" from the "Choose an assignment" dropbox, then click on "Browse..."; in the dialog box that opens now, navigate to the /home/cis505/git/hw0 folder, and select the submit-hw0.zip file you just created. Finally, click on the "Submit" button. You should see a message saying that your solution has been received. The submission system has an automatic checker that performs some basic checks on each new submission (e.g., whether it is a valid zip file, and whether it builds correctly). The idea is to give you some early warnings in cases where there is clearly a problem with your submission. This checker only runs every couple of minutes, so the results won't be available immediately. At first, the status of your submission will show up as "Pending..." (in orange); once the checker has run, the status will either change to "OK" or "FAIL". Please do not keep hitting the "Reload" button while you wait - just check back five minutes after you submitted the file! If the checks fail, there will be a link to a page with some additional information; you should look at this information and fix any problems. You can resubmit at any time before the deadline. Please note that the automatic checker is not exhaustive it mainly aims to detect a variety of simple problems with your submission using some heuristics. Hence, its status should not serve as a definite source of feedback: an OK status does not guarantee that your solution works correctly; likewise, a FAIL status does not necessarily mean that there definitely is a problem with your submission (e.g., a built failure could be because of the different compiling environments between Eniac, which is used by the checker, and the VM). If the checker reports a problem, you should have a close look at your submission to determine whether there are any real issues and fix them (if any). If, after having investigated the problem, you are convinced that everything is fine with your submission, feel free to ignore the checker s status, or check with us on Piazza if you are not sure. As a general rule of thumb, always make sure that the submitted zip package includes all the necessary files (e.g., README with all fields completed, MAKEFILE, and all the header and source files needed for compiling), and that your submitted solution compiles successfully and executes correctly in the VM.