This is one of a series of posts that introduce common information technology management activities to educational leaders.
In the vocabulary of IT technicians, imaging refers to the process of creating a file that contains the copy of a computer hard drive, then sending that to the hard drives of other computers. This strategy is particularly useful in situations where there are a large number of the same model installed in one place.
Imaging occurs in three steps. First, a single computer is configured exactly as it (and the others needs to be). The operating system and applications are updated, network settings established, printers configured, and old data files are removed and unused applications uninstalled, and any other maintenance tasks completed to create an image.
Second, the computer is restarted using software that bypasses the operating system on the hard drive. This may be done with software installed on a USB disk or that is stored at a network location. Typically, this includes a minimal operating system, so keyboards, network adapters, displays and similar tools function as the software to create and receive an image file loads. Third, the software imaging software is used to either create an image or receive an image (overwrite the current hard drive with the contents of a stored image).
There are several complicating factors in creating and using images including:
- Images are model-specific. If a school distributes five different models of laptops to teachers, then the IT staff must manage five images, and they must be sure to deploy the correct image to each model. More recent imaging software is minimizing the need to manage different images for each model, but the IT managers must still be clear about exactly which software titles (including drivers and extensions and configurations) need to be installed on each model.
- After making an image, it is essential that it be thoroughly tested before it is deployed. An error in setting up network printers on the image, for example, can make a whole fleet of computers unable to print if the image is deployed without being tested. Technicians must confirm all settings are correct to avoid the need to repeat the process.
- Some reconfiguration of recipient computers may be necessary. Several factors such as the types of software licenses that are on the hard drive used to create the image and the specifies of how devices are named on the network and the methods used to create user profiles determine how much unit-specific configuration is necessary after it receives an image.
- Imaging does irreversibly erase the contents of a hard drive, so data that has not been backup-up is lost. For this reason, technicians ask, “do you need the data on this computer?” more than once before reimaging a computer.
Typically, a technician will reimage a computer when it is observed to have unusual and difficult-to-troubleshoot symptoms; technicians are frequently heard to say, “well that is weird,” immediately before deciding to reimage a computer. If a technician suspects a computer has been infected by a virus or other malware, then he or she is likely to reimage it as well. The great advantage of this strategy from the technician’s point of view is that the system will be set back to a “known good” configuration with a well-known and standard practice. Further, in the hours that it takes for an image to overwrite the hard drive on a malfunctioning computer, the technician can attend to other repairs as the process completes without further input from the technicians once it is started. Imaging takes a few minutes to initiate, and several minutes to reconfigure unit-specific settings, but when the image is being received, the technician can attend to other work.
In addition to repairing malfunctioning computers, imaging is used for large upgrade and maintenance projects on fleets of computers. A common addition to the “to do” list of technicians over the summer is to “image the computer room” (which may be either desktop or laptop models). This finds a technician creating an image then sending it to all of the computers in the room. This does necessitate large amounts of data being transferred, so it can interfere with network performance when it is underway (which explains the need to do it over the summer). In all uses of imaging, it is a method of resolving software problems with great efficiency.