--- title: "How to use virtual PC and still save lots of room: differencing disks" url: "https://osherove.com/blog/2005/3/19/how-to-use-virtual-pc-and-still-save-lots-of-room-differenci.md" canonical: "https://osherove.com/blog/2005/3/19/how-to-use-virtual-pc-and-still-save-lots-of-room-differenci.html" published: "2005-03-19T17:20:00" updated: "2005-03-19T17:20:00" tags: ["Tips & Tricks"] author: "Roy Osherove" description: "Here's a great way to save some space on your hard drive with those big 'n nasty Virtual PC images: Differencing disks. The idea is simple: Start out with a hard drive image you're comfortable with, then create…" usage: "Licensed under CC BY 4.0 — reuse, quote and adapt with attribution (Roy Osherove, link to the original page)." license: "https://creativecommons.org/licenses/by/4.0/" --- # How to use virtual PC and still save lots of room: differencing disks By Roy Osherove March 19, 2005 In [Tips & Tricks](https://osherove.com/blog/category/tips-tricks) **Historical article** · Originally published March 19, 2005; technical details may be outdated. Here's a great way to save some space on your hard drive with those big 'n nasty Virtual PC images: Differencing disks. The idea is simple: Start out with a hard drive image you're comfortable with, then create "differential" images based on that image, where the only space they take is the "difference" between the two. That ends up saving a lot of room. So, for me this means I have a "base\_XP" drive which I've created in the usual manner using VPC. I'll use this to create my own new "versions" of this drive where I install various builds of VS 2005 and so on. The next step for me is to open the VPC console and click "file-Virtual Disk Wizard". In the wizard make sure you choose "differencing" disk when asked. You then have to point to the "base" drive (base\_xp in my case) which you will be differencing upon. It's important that you make that base drive as good as you need because you don't want to touch it later when other drives are depending on it. Now that you have finished making the drive, you just need to go to "file-new virtual machine wizard" and point to an existing virtual disk  - your new differencing drive. voila. You've just saved at least a couple of Gigs for each machine you're going to install off of that base disk. have fun. ## More in Tips & Tricks [All posts in Tips & Tricks](https://osherove.com/blog/category/tips-tricks) - Jun 8, 2005 ### [Logon as a different user on the same local desktop: in win 2003](https://osherove.com/blog/2005/6/8/logon-as-a-different-user-on-the-same-local-desktop-in-win-2.html) - Apr 20, 2005 ### [\[Word Shortcut of the day\] ALT-F3: Quick Auto Text](https://osherove.com/blog/2005/4/20/word-shortcut-of-the-day-alt-f3-quick-auto-text.html) - Feb 1, 2005 ### [Launcher: Clean auto-deployment and auto-updating code from Franklins.Net](https://osherove.com/blog/2005/2/1/launcher-clean-auto-deployment-and-auto-updating-code-from-f.html) - Jan 7, 2005 ### [Using Regex to return the first N words in a string](https://osherove.com/blog/2005/1/7/using-regex-to-return-the-first-n-words-in-a-string.html) --- ## About the author **Roy Osherove**: Senior Solutions Architect at AWS working on AI for production and AI-driven development; author of The Art of Unit Testing and Elastic Leadership, with about 20 years of consulting and training on unit testing, TDD, team leadership and continuous delivery. ### Sites - [RobotPaper](https://robotpaper.ai/): This blog: AI patterns and anti-patterns, AI and coding agents, and engineering leadership. - [osherove.com](https://osherove.com): Roy's personal site. Author of The Art of Unit Testing and Elastic Leadership; consulting and training on unit testing, TDD, team leadership and continuous delivery, plus about 20 years of blog posts. - [The Art of Unit Testing](https://www.artofunittesting.com): The Art of Unit Testing, 3rd Edition (Manning): readable, maintainable, trustworthy unit tests, plus TDD workshops in C#, JavaScript, Java and Kotlin. - [5whys.com](https://www.5whys.com): Roy's writing on software team leadership: self-organizing teams, surviving chaos, learning mode and the Elastic Leadership model. - [Pipeline Driven](https://pipelinedriven.org): Continuous delivery and DevOps practices: build patterns, pipeline-friendly testing, DevOps metrics and enterprise DevOps. - [Elastic Leadership](https://www.elasticleadership.com): Elastic Leadership, Roy's framework for software team leaders (survival, learning and self-organizing modes). ### Social - X: https://x.com/royosherove - LinkedIn: https://www.linkedin.com/in/osherove/ ### Contact - Contact form: https://forms.gle/jQSx5KoXvrVA1JCK7 ### License Licensed under CC BY 4.0 — reuse, quote and adapt with attribution (Roy Osherove, link to the original page). License: https://creativecommons.org/licenses/by/4.0/