.. _USBStorage: USB Storage ========================= Essential Materials ------------------- .. figure:: /_static/essentials/usbdrive.jpg :align: center :scale: 45% USB External Drive Essential Skill --------------- Objective ********* Students will understand the need for a USB storage device. Procedure ********* Working with geospatial data often means working with very large data sets. Processing geospatial data requires understanding where the input data sets are located and where you want the output results to be stored. In order to get the best results from your work you will need to be aware of both where your data is and how large it is. Where are some places your data could be? You data could be stored on the hard drive of the lab computer that you are sitting at. This location has its benefits and its drawbacks. On the up side the data is located on the local computer and will be processed quickly. The downside is that you will be unable to access your data if you are not at the lab computer. What if you needed to access the data at home or you had to use another computer because someone beat you to the classroom and “took†your computer? Another place you could keep your data could be in your GIS Home Folder on the shared storage K drive available on all school computers. This would allow you to access the data from any school computer or from anywhere using the virtual lab. The potential downside of using the K drive is that the drive is not directly connected to the computer that you will be running your analysis processes on. The K drive is a networked storage device which means it is accessed via the internet. This means that occasionally the K drive may be inaccessible due to maintenance or latency may cause your analysis processes to fail because they would not access the data needed in the expected timeframe. If you have ever had a process mysteriously fail and suddenly work on the next attempt this could be the cause if you were working with data stored on the K drive. So what is the solution for storing, accessing and working with your data? The the solution is to have the data in the right place at the right time. If you want to use your data in an analysis process the ideal situation is to have the data stored directly on the computer that will be running the analysis. If you you want to access your data while you are at home you will want to have your data stored on the K drive. In order to have your dta in the right place at the right time you may need an additional tool to help you. That tool is an external, portable storage device such as a USB based external hard drive. With a USB external drive you can keep a copy of your data with you whereever you go and you can also run programs from the external drive such as `7-zip Portable <http://portableapps.com/apps/utilities/7-zip_portable>`_ or `Firefox Portable <http://portableapps.com/apps/internet/firefox_portable>`_. What should your workflow be? Lets walk through the steps of a potential lab assignment. Pretend you're sitting at a lab computer. #. You download the files required for the lab to your lab computer. #. You extract the files and organize your lab assignment in folders (see the :ref:`Compression` and :ref:`Organization` section of this :ref:`GettingStarted` guide). #. You run the processes required for the lab to create derived data and map products. #. You copy the results of your work (your organized lab folder) to your USB storage. #. You also copy the folder to your GIS Home Folder. Now you have a copy to carry with you and a copy on the networked storage. #. Delete the lab folder on the lab computer to free the local disk space for other students. If you were continuing work on a lab assignment you would precede this workflow by copying the lab folder from your USB storage device to the computer. The benefits of this workflow are: #. You have a backup of your lab work #. Your analysis processes will run more quickly from local storage #. Failures are less likely to arise during processing when using local storage Consider obtaining and using a USB storage device for this and other courses.