### 2.1 Basics of Starting Scheme

Under unix, MIT/GNU Scheme is invoked by typing

    mit-scheme

at your operating system’s command interpreter. Under Windows, MIT/GNU Scheme is invoked by double-clicking on a shortcut. In either case, Scheme will load itself and print something like this:

    Copyright (C) 2015 Massachusetts Institute of Technology
    This is free software; see the source for copying conditions. There is NO
    warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

    Image saved on Wednesday November 25, 2015 at 3:49:35 PM
      Release 9.2.1 || Microcode 15.3 || Runtime 15.7 || SF 4.41 || LIAR/i386 4.118

This information, which can be printed again by evaluating

    (identify-world)

tells you the following version information. ‘`Release`’ is the release number for the entire Scheme system. This number is changed each time a new version of Scheme is released. ‘`Microcode`’ is the version number for the part of the system that is written in C. ‘`Runtime`’ is the version number for the part of the system that is written in Scheme.

Following this there may be additional version numbers for specific subsystems. ‘`SF`’ refers to the scode optimization program `sf`; ‘`LIAR/ARCH`’ is the native-code compiler, where ARCH is the native-code architecture it compiles to; ‘`Edwin`’ is the Emacs-like text editor. There are other subsystems you can load that will add themselves to this list.