Last altered 8/15/06
You do need to have the capability to run Quicktime. Many of the help files to come later are Quicktime movies.
[The above is a Quicktime movie, which you should be able to see and play straight off (you may need to turn your sound on, if you have separate speakers, and perhaps even turn the volume up). If you cannot, your browser should detect what it is and tell you what you have to do to see it (to download a plug-in, or whatever). If you have a really old browser, or one somewhat out of the mainstream, none of the above might happen. In which case you need to go to Quicktime or Quicktime download and equip your machine for viewing Quicktime.]
Many of the tutorials run Java Applets. You need to be able to see these. Here is one:
Main Connective Applet
You need to be able to see these (with most modern Web Browsers either you will be able to or the Browser itself will advise you what needs to be done).
One small item you can check straight away is that your Web Browser needs Java and Javascript enabled (almost certainly they will be, but it is possible, for one reason or another, that they are not). Find the Preferences for your Browser (it will be on one of the Menus, different places for different Browsers), then it needs to look like this:
Symbolic logic uses symbols, in particular (unicode) ∼ ∧ ∨ ⊃ ≡ ∀ ∃ ∴ or (html) ∼ ∧ ∨ ⊃ ≡ ∀ ∃ ∴ . If you cannot see these, that certainly is a problem to be solved. The solution is a) use a more modern web browser, or b) use a different web browser, or c) get a more modern computer and try (a) and (b) again. [What is happening here is that that the symbols are in unicode and each symbol has its own unique unicode. However, particular fonts on a computer display only a relative few of 60,000 odd unicode characters. If a particular font cannot display a symbol, changing fonts to a different font may help (and some host computers automatically do this). The web browsers can display many unicode symbols, and they normally do so by means of an html conversion. Each year, the browsers can display more and more. Our logical symbols are commonplace mathematical symbols so they should be displayed. But if you have a really old browser.... you may see either nothing, or a default character like a square box ▢.]
Almost everything you will want to do can be done via applets (described above). And all the web page Notes use only applets. But for some purposes you may want to download and run the Deriver downloadable application. The next section or two addresses that.
(If you do not understand the next little section, jump ahead to the explanation.)
[There is a little script hidden under here, which is testing the configuration of your computer. It may suggest courses of action to you. Sadly there are some non-standard items out there which the script cannot test. You may just have to see whether everything works, then follow the recommendations.]
This should give you Web Start via JNLP. It will download the program, tell you that it is from me, and advise you NOT to trust me. You need to trust me if you want to run the program, so ignore their advice.
Some browsers will offer either to a) run a jnlp program or b) save it to disk (and many browsers automatically do both). If you have to choose, you probably want to save 'deriver.jnlp' to disk, then if ever you double click on that file (whether you are online or not) it will run Deriver.
Enjoy!
The program is written in Java. This means it should run on any machine
that has a Java Virtual Machine on it, which, in turn, should be any
machine (Windows, Macintosh, Sun, Linux, etc.) that has a modern
web browser (Firefox, Internet Explorer, Netscape, Mozilla, Safari, Opera, etc).
on it.
The Java it uses is 1.2 or later which is relatively recent (2003) but
not bleeding edge. This Java VM will be on all newer machines.
But also it should be on most older machines. Everyone wants their Web
Browsers to run properly. And all machines like Macintoshes, Windows,
etc. automatically update their Java VMs to ensure this happens.
However a) a nine year old Windows 95 machine, for example, which has
been kept isolated from updates will not run the program, and b) there are rivalries between Sun and Microsoft and in part this
manifests itself with Microsoft products like Windows not updating
properly Sun technologies like Java. In the worst case, the User will
have to ensure that the Java VM is recent. See, for example, Java Technology Help.
Sun have an elegant delivery technology called Java Web Start (sometimes associated with the acronym JNLP). This is a generalization
of Java Applets, which most everyone is familiar with on their Web
Browsers (like, for instance, many of those animated images). With Web Start, the User sees and clicks on a link on a Web Page. The
technology first checks whether the most recent Java VM and Web Start
technologies are installed on the client machine. If not, it offers to
install them. Then Web Start downloads the program it is to run to the
client machines, and launches it. This is on the first time around. On
second and subsequent times, Web Start checks whether the version of
the program on the client machine is the most recent version; if so, it
runs it; if not, it downloads the most recent one and runs it replacing
the existing one. Once the program has been downloaded it can be run on
its own, without the client having to connect to the Web or the
Internet.
Web Start solves several problems at once:- a) the delivered program
will run on any machine (Mac, Windows, etc.), b) the delivered program
is installed automatically (consider the alternative, we have perhaps
80 machines in a lab, we have to go round each of them inserting an
installation floppy disk or downloading from a network), and c) the
delivered program is always up to date (consider the alternative, we
have 80 machines in a lab with the installed program, the author finds
a bug and releases an update, so we have to go round all 80 machines
again and install the updated version).
Running or executing a program from a distant source on your own
machine is always a red flag. Viruses, worms, trojan horses, etc are
all programs from remote sources which get to run on your machine. And
they do bad stuff.
There needs to be direct protection here or trust. In the case of Java
Applets, they run on the client machine in an isolated security sandbox
which prevents them from doing anything bad-- in essence they no real
access to the client machine. But with many intending applications
isolation is no good. For example, if the application was a word
processor the client needs to be able to save the documents that are
produced, and saving a file does really access the client machine.
So, with a word processor (or, indeed, a logic application which saves
to files) there needs to be trust. There needs to be two parts to
trust:- that the producer and the product are trustworthy, and that the
delivered program is a properly intact and unaltered version of the
product.
The first part of this is routine. When you go into your software
supplier and buy Microsoft Office (or a logic program) on CD, you
expect that this software will not deliberately and maliciously damage
your computer (like by erasing your hard disk). (Sometimes mistakes or
errors are made, but that is life.)
The second part needs a little more. If you downloaded Microsoft Office
(or a logic program) over the Internet, you'd like to know that the
program really came from its producer and that the program was unaltered. This assurance can be provided, and it is done within Java
Web Start. The producer encrypts the program, and digitally signs it
with an authenticating certificate. The receiver then can be sure that
the program came from, say, Microsoft, and that it is unaltered.
With the signing and authentication, one pays an issuing
authority to check that you are who you say you are (passport, id
etc.) and to provide you with 'keys'. This would cost someone
like me, perhaps $250 a year-- which is not horrendous, but also I have
no motivation to spend that at present. There is a workaround. I
just issue myself a security certificate to myself (that is, I am
trustworthy and I'll provide you with a certificate that I produce that
says so).
You probably do not have the Java Run Time Environment, and Java Web Start, installed on your computer. This is explained above, but you could probably do quick fix from How do I install the Java Run Time Environment and What is Java Web Start and How is it Launched.
Well, they should run properly (but they don't).
Firefox (2.0, 1.5)
Displays symbols properly. Copies, pastes, drags and drops to Deriver properly. (Perfect).
Safari (2)
Displays symbols properly. Copies, pastes, drags and drops to Deriver properly. (Perfect).
Firefox (2.0, 1.5)
Displays symbols properly. Copies, pastes, drags and drops to Deriver properly. (Perfect).
Internet Explorer
Displays symbols properly. Copies, pastes, drags and drops to Deriver properly. (Perfect).
This program runs on the 'Java Virtual Machine' or 'Java Runtime Environment' on the host computer (your home computer). But if your Java Runtime Environment is out of date, especially way out of date, that offers an invitation to erratic behaviour. Windows and Macintosh machines, and probably others, automatically update their JREs. But you can refuse that update (and maybe some Users do not understanding what a Java Runtime Environment is).
But if your version of Deriver is doing something odd, like not displaying the symbols properly, check that your JRE is up to date. Check Java Technology Help or Java for Mac OSX or JRE Installation Instructions
2/6/06
One student seems to have most of the logical symbols working and displaying properly, but not 'therefore'.
'Therefore' is unicode '\u2234' which is html '∴' which is nowadays abbreviated as html '∴' eg look at http://www.w3.org/Math/characters/html/symbol.html.
Let me write both the html versions, in html
first: ∴
second: ∴
I think you should be able to see both these, and I probably mix them about half and half in the text. [I used to use ∴ but ∴ is easier to remember.]
If you cannot see these in your browser
If you cannot see them within Deriver itself eg in the symbol palette or in the journal (try copying and pasting to the journal, try editing the html itself and put the symbols in and see if they display)