+* We'll give examples using the packaging system shared by Debian and Ubuntu,
+ and we'll assume that those of you using different packaging systems will know
+ how to make the relevant substitutions.
+
+
+**For everyone**, a general item to take note of is what "processor architecture" your machine is running. Three of the possibilities are:
+
+* One of Intel's i386, i486, i586, i686 architectures. These are collectively known as "x86" or "IA-32" or sometimes just "32-bit".
+* Intel or AMD's x86\_64 architecture. This is also called "x64" or "amd64" or "IA-64" or sometimes just "64-bit". (Note that these *aren't* "x86" machines, even though "x86\_64" starts with those letters.)
+* ARM or some other architecture. These are generally lower-powered machines, like iPads. Some of the software we're proposing *might* in principle be capable of running on such machines, but installers don't seem to be available. We'll assume you have access to an x86 or x86\_64 machine.
+
+On Linux or Mac OS X, you can open a terminal and type `uname -m`. If the
+result is "x86\_64", then you've got x64/64-bit. If it's "i386" or something
+like that, then you've got x86/32-bit. I think that Mac OS Xs from 10.7 / Lion
+forward have all been x86\_64-only.
+
+On Windows,
+[here is a page that can help you figure this out](http://windows.microsoft.com/en-us/windows/32-bit-and-64-bit-windows).
+I think that most machines running Windows XP will be x86/32-bit (unless it's
+a version of Windows with "64-bit" or "x64" in its title); machines running
+Windows Vista or Windows 7 or Windows 8 could be running either x86/32-bit or
+x64/64-bit.
+
+
+## PLEASE REPORT PROBLEMS (AND SOLUTIONS!) ##
+
+We haven't tested these instructions ourselves, and they're not explicit
+step-by-step instructions in any case. If you encounter troubles, please email
+to let us know so that we can amend the instructions to help others. If you
+figure out how to fix the problem youself (and please do), please also write
+with suggestions how we can change these instructions to make the process
+easier and more straightforward for others.
+
+
+## Getting Scheme ##
+
+**Scheme** is one of two or three major dialects of *Lisp*, which is a large family
+of programming languages. The other dialects are called "Common Lisp" and "Clojure".
+Scheme is the more clean and minimalist dialect, and is what's mostly used in
+academic circles.
+
+* In your web browser:
+
+ There is a (slow, bare-bones) version of Scheme available for online use at <http://tryscheme.sourceforge.net/>.
+
+Scheme itself has umpteen different "implementations", which share most of
+their fundamentals, but have slightly different extensions and interact with
+the operating system differently. One major implementation is called [Racket](http://racket-lang.org),
+and that is what we recommend you use. (A few years back they were called PLT Scheme, but then
+they changed their name to Racket.)
+If you're already using or comfortable with
+another Scheme implementation, though, there's no compelling reason to switch.
+
+
+Another good Scheme implementation is [Chicken](http://www.call-cc.org). For our purposes, this is in some respects
+superior to Racket, and in other respects inferior. If you have any issues with installing or using Racket, you could
+try this out instead. You might even want to install both.
+
+<!--
+Racket doesn't have R7RS-small, and won't anytime soon.
+Other R7RS-friendly: [Gauche](http://practical-scheme.net/gauche), [Chibi](https://code.google.com/p/chibi-scheme).
+-->
+
+Racket and Chicken stand to Scheme in something like the relation Firefox stands to HTML. They are two programs (or platforms) among others for working with the Scheme language; and many of those programs (or web browsers) permit different extensions, have small variations, and so on.
+
+Racket has several components. The two most visible components for us are a command-line interpreter named "racket" and a teaching-friendly editor/front-end named "DrRacket". You will probably be working primarily or wholly in the latter.
+<!-- "racket" used to be mzscheme, "DrRacket" used to be DrScheme -->
+
+The current version of Racket is 6.1.1 (released November 2014).
+
+* **To install in Windows**
+
+ Go to <http://racket-lang.org/download/>. Download and install the "Windows x64" version. (Or the "Windows x86" verson if you have an older, 32-bit system.)
+
+* **To install on Mac without MacPorts**
+
+ Go to <http://racket-lang.org/download/>. Download and install the option for your system, most likely "Macintosh
+ OS X (Intel 64-bit)".
+
+ After you copy the files from the Installation disk to your /Applications folder, I think it's helpful to do these additional steps. In a Terminal, type:
+
+ sudo ln -s /Applications/Racket*/DrRacket.app /Applications/
+ sudo ln -s /Applications/Racket*/bin/racket /usr/bin/
+
+ Then you can launch Racket either by double-clicking the DrRacket icon in
+ your Applications folder (this gives you the GUI interface); or by typing
+ `racket` in a Terminal (this gives you the command-line version).
+
+* **To instead install Chicken Scheme on Mac without MacPorts**
+
+ Here are the exact steps I just verified worked. Note that I *first installed the Haskell Platform*, described further down this page; that installed some developer tools that were needed to build and install Chicken. If you don't know how to open a Terminal, move between directories, copy / rename / delete files and so on, then you're probably best off not doing this. You could break something.
+
+ 1. Go to <http://code.call-cc.org>, and click the "Source code" link near the top. Current version is 4.9.0.1, released November 2014. This should fetch a file to your download folder, and will probably automatically unpack that file into a folder, "chicken-4.9.0.1". Click on that folder and press command-C / Copy, then open a Terminal.
+ 2. In the terminal type `cd` followed by a space, then press command-V / Paste. Then press enter. This will move your session into the folder you just downloaded.
+ 3. Type `less README` and read that file.
+ 4. Type `sudo mkdir -p /usr/local`
+ 5. Type `make PLATFORM=macosx XCODE_DEVELOPER= XCODE_TOOL_PATH=/usr/bin`
+
+ The options starting with `XCODE_` are to tell the Chicken build scripts that I've got the developer tools installed in my main system, rather than as part of Xcode. (That's where the Haskell Platform installer put them.) Continuing:
+
+ 6. Wait a while while Chicken builds.
+ 7. If it finishes with no errors, then type `sudo make PLATFORM=macosx XCODE_TOOL_PATH=/usr/bin install`. This will prompt you for your account password, and then install Chicken underneath your `/usr/local` directory.
+ 8. At this point you can type `which chicken`. If it gives you an answer of "/usr/local/bin/chicken", then skip to the next step. Else you should type `echo 'export PATH=/usr/local/bin:$PATH' >> ~/.bashrc`, then exit and restart your Terminal session.
+ 9. In your terminal, type `chicken-install -sudo r7rs datatype matchable monad`. This will download, build, and install a few extensions (Chicken calls them "eggs") relevant to ideas we'll be working with in this course.
+
+* **To install on Mac with MacPorts**
+
+ Unfortunately, MacPorts doesn't have Racket itself available. It only has an older version from when they still called
+ themselves PLT Scheme. And even then, it only has the command-line program "mzscheme" (what's nowadays called "racket"); it
+ doesn't have the GUI program that corresponds to what's now called "DrRacket". You can install mzscheme by opening a Terminal
+ window and typing:
+
+ sudo port install mzscheme
+
+ <!-- mzscheme v4.1.5, from March 2009; latest mzscheme is 4.2.5, from April 2010 -->
+
+ If you want the GUI components, I think you'll need to use the
+ "Mac/without MacPorts" installation options above. Or you could try the Chicken Scheme implementation instead of Racket. This is more current.
+ To do that, type:
+
+ sudo port install chicken readline
+
+ <!-- chicken v4.8.0.2, from Feb 2013; latest available is 4.9.0.1, from Nov 2014 -->
+
+ Whether you use mzscheme or Chicken, I recommend also typing:
+
+ sudo port install rlwrap
+
+ then if you ever use the command-line program `mzscheme` (or `racket`, for that matter), you should start it by typing `rlwrap mzscheme` (or whatever). This gives
+ you a nice history of the commands you've already typed, which you can scroll up and down in with your
+ keyboard arrows.
+
+* **To install on Linux**
+
+ Use your packaging system, for example, open a Terminal and
+ type:
+
+ sudo apt-get install racket
+
+ It's very likely that your packaging system has some version of
+ Racket available, so look for it. However, if you can't find it you
+ can also install a pre-packaged binary from the Racket website at <http://racket-lang.org/download/>.
+ Choose the option for your version of Linux (Ubuntu and Debian are available).
+
+ As above, I recommend you also type:
+
+ sudo apt-get rlwrap
+
+ then if you ever use the command-line program `mzscheme` (or `racket`), you should start it by typing `rlwrap mzscheme` (or whatever). This gives
+ you a nice history of the commands you've already typed, which you can scroll up and down in with your
+ keyboard arrows.
+
+
+## Getting OCaml ##
+
+**Caml** is one of two major dialects of *ML*, which is another large family of
+programming languages. The other dialect is called "SML" and has several
+implementations. But Caml has only one active implementation, OCaml or
+Objective Caml, developed by the INRIA academic group in France.
+Sometimes we may refer to Caml or ML
+more generally; but you can assume that what we're talking about always works more
+specifically in OCaml.
+
+It's helpful if in addition to OCaml you also install the Findlib add-on and/or the [OPAM](https://opam.ocaml.org) "package manager."
+These will make it easier to install additional add-ons further down the road.
+However, if you're not able to get them working, don't worry about it much.
+
+The current version of OCaml is 4.02.1 (released October 2014).
+<!-- 3.12.1 July 2011; 4.00.1 Oct 2012; 4.01.0 Sept 2013; 4.02.0 Aug 2014; 4.02.1 Oct 2014 -->
+
+
+* In your web browser:
+
+ There is a (slow, bare-bones) version of OCaml available for online use at <http://try.ocamlpro.com/>.
+
+
+* **To install in Windows**
+
+ Go to <http://caml.inria.fr/download.en.html>.
+ You can probably download and install the
+ "Self installer for the port based on the MinGW toolchain"
+ even if you don't know what MinGW or Cygwin are.
+ Some features of this require Cygwin, but it looks like
+ it should mostly work even for users without Cygwin.
+ At the time of this writing, only an installer for an earlier
+ version of OCaml (4.01.0, from September 2013) is available.
+
+ To install the Findlib add-on, you must have the
+ Cygwin system installed. We assume few of you do,
+ so we're not going to try to explain how to do this.
+ If you want to figure it out yourself, go to the
+ Findlib website at <http://projects.camlcity.org/projects/findlib.html>.
+
+* **To install on Mac without MacPorts**
+
+ *Instructions coming*
+
+* *Another instruction page focuses on [OPAM](http://ocaml.org/docs/install.html), also [this](https://opam.ocaml.org).*
+
+* *[More details about installing OCaml on Macs, if needed](http://mirror.ocamlcore.org/wiki.cocan.org/getting_started_with_ocaml_on_mac_os_x.html)*
+
+ <!--
+ To install OCaml 3.12 (just released this summer), go to
+ <http://caml.inria.fr/download.en.html>
+ and download and install the "Binary distribution for Mac OS X"
+
+ To install the Findlib add-on, you'll need the Xcode development tools
+ to compile it yourself. Once you get that far, it's probably easiest
+ for you to install MacPorts and just install things using the MacPorts
+ instructions. (Use the MacPorts version of OCaml, instead of installing
+ the package from the caml.inria.fr website, as described above)
+ However, if you do have Xcode, and want to do without MacPorts, then
+ what you need to do is download Findlib from
+ <http://download.camlcity.org/download/findlib-1.2.6.tar.gz>.
+ Unpack the download, open a Terminal and go into the folder you just
+ unpacked, and type:
+
+ ./configure
+ make package-macosx
+
+ This will build an installer package which you should be able to
+ double-click and install.
+ -->
+
+* **To install on Mac with MacPorts**
+
+ You can install the current version of OCaml (4.02.1, from October 2014),
+ together with the Findlib add-on and OPAM package manager, by opening a Terminal and typing:
+
+ sudo port install ocaml caml-findlib opam
+
+ As with Scheme, it's helpful to also have rlwrap installed, and to start OCaml as `rlwrap ocaml`. This gives
+ you a nice history of the commands you've already typed, which you can scroll up and down in with your
+ keyboard arrows.
+
+* **To install on Linux**
+
+ Use your packaging system, for example, open a Terminal and
+ type:
+
+ sudo apt-get install ocaml ocaml-findlib opam
+
+ That will install a version of OCaml and the Findlib add-on and OPAM package manager.