The first version of Scratch was implemented in Squeak. OpenQwaq, a virtual conferencing and collaboration system, is based on Squeak. Squeak is also used in the Nintendo ES operating system License Squeak 4.0 and later may be downloaded at no cost, including source code, as a prebuilt virtual machine image licensed under the MIT License, with the exception of some of the original Apple code, which is governed by the Apache License. Squeak was originally released by Apple under its own Squeak License. While source code was available and modification permitted, the Squeak License contained an indemnity clause that prevented it from qualifying as true free and open-source software. In 2006, Apple relicensed Squeak twice. First, in May, Apple used its own Apple Public Source License, which satisfies the Free Software Foundation's concept of a Free Software License and has attained official approval from the Open Source Initiative as an Open Source License. However, The Apple Public Source License fails to conform to the Debian Free Software Guidelines. To enable inclusion of Etoys in the One Laptop Per Child project, a second relicensing was undertaken using the Apache License. At this point, an effort was also made to address the issue of code contributed by members of the Squeak community, which it was not in Apple's power to unilaterally relicense. For each contribution made under the Squeak License since 1996, a relicensing statement was obtained authorizing distribution under the MIT license, and finally in March 2010, the end result was released as Squeak 4.0, now under combined MIT and Apache licenses. Squeak virtual machine The Squeak virtual machine is a family of virtual machines (VMs) used in Smalltalk programming language implementations. They are an essential part of any Smalltalk implementation. All are open-source software. The current VM is a high performance dynamic translation system. The relevant code is maintained in the OpenSmalltalk/opensmalltalk-vm repository on GitHub. Other Squeak virtual machines CogVM RoarVM SqueakJS Stack interpreter VM RSqueak/VM TruffleSqueak See also List of open-source programming languages Alice (software) Croquet Project Pharo Seaside (software) References External links Programming languages Apple Inc. software Class-based programming languages Disney technology Dynamic programming languages Dynamically typed programming languages Educational programming languages Free educational software Programming languages created by women Smalltalk programming language family Software using the MIT license Visual programming languages High-level programming languages Multi-paradigm programming languages Cross-platform free software Programming languages created in 1996 1996 software