Sector-based imaging vs. file-based imaging: What's the difference?

Computer imaging often gets a bad rap because it can be a lot of work if you do it manually or rely on disk imaging software that costs way too much time to use. (Some folks even shun it altogether by using Windows Autopilot and Microsoft Intune instead, but that’s a discussion for another day.) 

Many conventional disk imaging tools are sector based, which is ideal for backups. But when it comes to image deployment, sector-based imaging software lacks the efficiency, flexibility, and hardware independence of file-based imaging solutions. We’ll walk you through the differences and pros and cons of each approach so you can decide what works best for you.

What is sector-based imaging? 

Sector-based imaging — AKA disk cloning — is the process of creating an exact copy of a hard drive and capturing it as one monolithic image. That bulky image includes the operating system, software applications, and all user files on the machine. The captured image is then deployed wholesale to a compatible device. Sector-based imaging tools copy hard disk data sector by sector (hence the term) before storing it as an image file on a storage device, like a USB stick or hard drive.

Advantages of sector-based imaging 

The good thing about sector-based imaging software solutions is that they’re not limited to a specific type of operating system, and they’re great backup tools. 

Platform independent 

Because sector-based imaging records data at the binary level, it works with any type of operating system, device, or even cloud environment. A sector-based imaging tool can copy any device it can read. 

Ideal for image-based backups 

Sector-based imaging is ideal for creating image-based backups of specific machines. Should a computer or server get accidentally deleted, corrupted, or personally victimized by unforeseen coffee spillage, you can easily recover whatever was lost by applying the respective image.

Limitations of sector-based imaging 

On the flip side, sector-based imaging comes with certain downsides. Sector-based images have limited compatibility with devices that are different from the source machine, and admins have less flexibility to manipulate images during the deployment process. 

Limited compatibility of sector-based images 

Applying a sector-based image on a dissimilar machine is like wearing a suit that’s tailored for someone else — the legs would be too tight, and you won’t be able to walk without ripping the seams. Sector-based images contain configuration and device drivers that are specific to the source machine. Unless you apply the image to an identical or compatible machine, these differences may cause issues during and after deployment. 

Use of physical reference machines 

In general, sector-based imaging works better with physical reference machines (which should not be used for other purposes). Ideally, you need one reference machine per image and one image for every make and model you support. And that means a collection of unusable machines just gathering dust. The more diverse your fleet of user devices, the more budget, effort, and space it takes to store and manage your physical reference machines.

Limited flexibility during deployment 

Sector-based images can be difficult to modify — especially if you need to make dynamic changes during deployment or in restricted environments, like Windows Preinstallation Environment (Windows PE). A sector-based imaging system also doesn’t allow you to slipstream custom apps or scripts (to automate postdeployment tasks) with your operating system image. 

Right, you get the picture. Sector-based imaging software may not be a suitable option in some scenarios. Well, what then? Friends, IT colleagues, and esteemed readers, we present to you a more versatile alternative: file-based imaging solutions.

What is file-based imaging? 

File-based imaging is the process of creating an operating system image by copying individual files and folders from a reference machine’s hard disk or virtual disk. File-based imaging tools take a modular approach, allowing you to capture images that consist only of the unique operating system files, software, and settings that you need and not the entire disk. You can choose to leave out stuff like hardware drivers to create golden images that are compatible with any device make or model. Your image, your rules.

Advantages of file-based imaging 

Unlike sector-based imaging, file-based imaging allows you to keep your images hardware independent, your setup lean, and your deployments flexible. 

Hardware independence 

With file-based imaging, you can create generic images that contain only selected operating system files and core applications, such as Microsoft Office and Adobe Reader — while excluding machine-specific files, such as drivers. Such golden images are hardware independent and can be deployed to any device, regardless of make or model. It’s like having one tie that goes with every shirt in your closet. And with fewer images to manage, you spend less time keeping them up to date. 

Virtual reference machines 

Virtual machines (VMs) are ideal for file-based imaging. Using VMs lets you create and capture clean, high-quality images in a controlled environment. VMs also save you a ton of space since one physical device can run multiple VMs at the same time. No more closets of reference machines gathering dust! And the best part is, you can get virtualization software like Oracle VM VirtualBox and VMware for free. 

Single-instance storage 

File-based imaging uses single-instance storage to optimize file storage capacity. Instead of storing multiple copies of the same data chunks, duplicates are replaced with a pointer to the original copy. Whether you’re capturing from one or more reference machines, you can consolidate the information more efficiently within a single file.

Deployment flexibility 

File-based imaging tools give you a lot more flexibility and control during the deployment process. You can dynamically slipstream different custom apps, device drivers, and scripts with your operating system image to create deployment packages for different devices or user groups. Because of their modular nature, file-based images are also easy to customize and update. 

Limitations of file-based imaging 

Some file-based imaging tools work exclusively with .WIM file formats — used to store Windows operating system images. Such tools are not compatible with non-Windows systems, like macOS, and you need to look for other alternatives to keep your Apple devices up to date. 

Sector-based imaging vs. file-based imaging: How to choose 

With so many options out there, how do you decide what’s the best computer imaging solution for your organization? Try answering the following questions to identify your requirements and selection criteria. 

• What is the main business problem you’re trying to solve? 

• What is your primary use case — backing up specific machines or keeping endpoints up to date? 

• Are you supporting a Windows environment, a non-Windows environment, or a combination of both? 

• Are you supporting diverse hardware and user groups? 

• How much budget and IT resources do you have? 

In general, sector-based imaging software is best for creating backups of unique machines. For more flexible, streamlined image deployments across hardware-diverse organizations, you’re better off using file-based imaging tools. 

Seeing is believing. We hear ya. You can download a 15-day free trial to learn why SmartDeploy’s file-based Windows imaging solution trumps clunky sector-based imaging tools, like Symantec Ghost Solution Suite, and free options, like Microsoft Deployment Toolkit. Discover firsthand how SmartDeploy lets you simplify computer imaging workflows, reduce deployment workloads, and keep your Windows images up to date — all without breaking a sweat.