MIT Scheme Release 7.4

This is the home page for MIT Scheme Release 7.4.

Note that MIT Scheme Release 7.5 supercedes this release. If you plan to use MIT Scheme on one of the platforms supported by Release 7.5, we strongly recommend using the newer version. The home page for release 7.5 is here.

The main home page for MIT Scheme is
The information on this page is also available via FTP at

Release 7.4 is for x86 (Intel Architecture 32) machines only. We provide versions that run under the following operating systems: GNU/Linux, IBM OS/2, and Microsoft Windows (3.x, 95, 98, and NT). We no longer support DOS without Windows. Other users have ported this code to FreeBSD, NetBSD, and BSDI BSD/OS.

Release 7.3 supports other machine architectures. It can be found at or

MIT Scheme is free software. This means that you may copy and modify this software, and redistribute either the original software or a modified version. Please see the license for full details.

  • Release status
  • Documentation
  • Download
  • Future Plans

  • Release status

    The GNU/Linux, OS/2, and Win32 releases are at revision 7.4.7
    The BSDI release is at revision 7.4.5
    Everything else is at revision 7.4.2


    Documentation for MIT Scheme is available in a variety of formats. There are two manuals: the MIT Scheme Reference Manual and the MIT Scheme User's Manual. (There is also a note describing MIT Scheme's macros, which are not hygenic. We will probably implement an R5RS-compliant macro facility in 2000 or 2001.)


    MIT Scheme 7.4 is available in binary form for a variety of systems. For each system, there are three files.
    1. The main binaries file contains all of the files necessary to run MIT Scheme.
    2. The runtime debugging information file provides debugging information for the runtime library, allowing you to see the source code for the internals of the runtime library when you are using the debugger (without this information, the debugger shows minimal details and no source code).
    3. The Edwin debugging information provides debugging information for the Edwin editor's internals, which is useful to those who customize Edwin.
    Recommendations: Most users should install the main binaries and the runtime debugging information. If you are short on disk space, install only the main binaries. If you will be customizing Edwin, install the Edwin debugging information.
    These were compiled on a system running Debian GNU/Linux 1.3.1. The executables are ELF binaries that depend on libc5 and libX11; they should work on most GNU/Linux systems. If you don't have libX11 on your system, you can use these binaries instead. Otherwise, you will have to compile executables for your system; read these instructions for details.
    These were compiled on a system running FreeBSD 2.1.5-RELEASE.
    These were compiled on a system running BSD/OS 3.0.
    IBM OS/2
    These were compiled on a system running OS/2 Warp 4.0 with IBM VisualAge C++ 3.0. Includes documentation in OS/2 .inf format.
    Microsoft Windows
    These were compiled on a system running Windows NT 3.51 using Microsoft C/C++. Includes documentation in Windows .hlp format. Please note that this release will not work properly if installed in a directory whose name contains spaces or other unusual characters. This will be fixed in the next release.

    If you are using Windows 3.1 and you don't have Win32s installed, download and install pw1118.exe. Do not install pw1118.exe on any version of Windows other than 3.1.

    This software is distributed in ZIP format. If you need a program to unpack the software, you can use this copy of unzip.exe. Alternatively, recent versions of the Info-Zip "unzip" program will also work.

    Full source code for MIT Scheme is available. Note that you cannot build a working system from the source unless you have a working MIT Scheme compiler to do the compilation. This means that if the above binaries don't work on your system, it is pointless to try building a custom set of binaries from the source code.

    There is one exception to this statement: the code in the "microcode/" subdirectory of the source tree is C code, and contains nearly all of the operating-system specifics. You can compile the C code to produce executables and combine that with one of the existing packages to make a new package. See these instructions for an outline of the procedure using GNU/Linux as an example.

    Future Plans

    Version 7.5 of this software was released in January 2000. See the Scheme 7.5 page for details.

    This page is maintained by Chris Hanson.
    Last changed on May 28, 2001.