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In June, Databricks open-sourced all the Delta Late APIs as part of the new Delta Lake 2.0 release. This put a definitive end to criticism from its competitors like Cloudera, Dremio, Google (Big Lake), Microsoft, Oracle, SAP, AWS Snowflake, HPE (Ezmeral) and Vertica, who had doubted whether Delta Lake was open source or proprietary.
“The new announcement should provide continuity and clarity for users and help counter confusion (stoked in part by competitors) about whether Delta Lake is proprietary or open source,” said Matt Aslett, research director at Ventana Research.
This is not the first time there has been an ambiguity regarding the open-source nature of a tool. The best example is Microsoft’s VS Code.
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Last month, Rukshan Ranatunge, Member – FHIR Implementation Architecture and Technical Advisory Group Ministry of Health – Sri Lanka, mentioned in a blog post that he is switching from VS Code to VS Codium. In the post, he talked about VS Code not being open source and also about what makes VS Code proprietary.
Also, in June, Licio Lentimo, Cybersecurity Technical Mentor at CYDEO and software developer, tweeted, “VS Codium is the open-source alternative of VS Code. Interestingly, Microsoft’s VS Code is not fully open source as many previously thought.”
What is VS Code?
A prominent aspect of the source code editor is that it can be customised using extensions. These extensions support new programming languages, themes, and debuggers and perform static code analysis.
With the built-in source control feature, users can access control settings and view changes made in the current project. Moreover, this feature also allows users to create repositories and make a push and pull requests directly from the Visual Studio Code program.
How open is VS Code?
Microsoft released the beta open-source version of VS Code in November 2015. At the same time, it open-sourced the VS Code repository. However, this does not mean that VS Code is open-source. Instead, it’s more accurate to say that VS Code is built on an open-source project called Code-Open Source Software (Code-OSS). Code-OSS is the core layer of VS Code. It is available on GitHub under the standard MIT License.
The GitHub repository (Code-OSS) is where Microsoft develops the VS Code product. Here, the developers write code and modify it. They also publish their roadmap and monthly iteration in the GitHub repository.
However, Microsoft VS Code is a Microsoft licensed distribution of ‘Code – OSS’ that includes Microsoft proprietary assets and features like Visual Studio Marketplace integration and telemetry system that are not available in Code-OSS. Thus, Microsoft follows an ‘open core model’ for VS Code and is not actually open-source.
In an open core model, the company offers certain limited features that form the core of the product as free and open source (FOSS) software, while several add-on features are released as proprietary.
Not just Microsoft but several other companies deploy the open core model. For example, Google built Chrome on Chromium, an open-source browser and then modified it to incorporate proprietary Google features, which is released as proprietary freeware. The same is true for the Oracle JDK, Xamarin Studio and JetBrains. These applications have been built on top of OpenJDK, MonoDevelop and IntelliJ, respectively.
“Microsoft modifies VS Code in a way that a non-Microsoft VS Code fork can’t use extensions from the official Microsoft VS Code store. Not only that, some of the VS Code extensions developed and released by Microsoft will only work in the VS Code released by Microsoft and won’t work on non-Microsoft VS Code forks,” mentioned Ranatunge in his blog post.
Microsoft has made similar moves in the past. It modified the open-source cross-platform IDE MonoDevelop as Visual Studio for Mac. The Visual Studio for Mac has three versions- for students, professionals and enterprises. While the students’ version is free and supports classroom learning, individual developers and small companies must log in via IDE to access the other versions.
In 2021, Microsoft abruptly removed the Hot Reload functionality from the open-source .NET SDK, only to revoke it later as it had enraged the .NET community.
Move towards VS Codium
As stated, Microsoft follows an open-core model for VS code. Therefore, developers who want access to the full open source code that is MIT licensed will have to download the code from the repository and then build the VS code on their own.
The task is cumbersome for most users. This is where VS Codium comes into play. VS Codium is fully open-source software binaries of VS Code licensed under the MIT license. With VS Codium, developers do not need to download and build from the source. Instead, the VS Codium team builds VS Code from the source repository and uploads the binaries to GitHub. “VS Codium is a clone of Microsoft’s Visual Studio Code. This project’s sole aim is to provide you with ready-to-use binaries without Microsoft’s telemetry code,” mentioned Abhishek Prakash, creator of It’s FOSS (a web portal focused on open source), in a blog.
With telemetry tracking, developers are often flooded with unnecessary advertisements for premium versions of various extensions they use. VS Code gives users the option to install Microsoft and third-party extensions. Unfortunately, these extensions may be collecting their usage data, which cannot be disabled by disabling telemetry tracking.