The default APL font for NARS2000 (its APL Interpreter session, function editing, screen display and printing purposes) and this wiki is SImPL medium(Unicode based), SImPL, or APL385 Unicode.
If the APL characters in the articles don't display correctly, you may obtain a copy of the SImPL medium font by downloading the current NARS2000 binary, or the SImPL font from here, or the APL385 Unicode font from here. Normally font and file SimPL-Medium.ttf may be found in your downloaded NARS2000 program folder, e.g. C:\Program Files (x86)\NARS2000 (32-bit program) and or C:\Program Files\NARS2000 (64-bit version).
If they still don't display correctly, download FireFox.
Default Keyboard Layout
NARS2000 default APL keyboard layout, based on the SImPL medium font, is found here, on SudleyPlace.com. Printing the keyboard layout and keeping it in front of you while using NARS2000 - provides a handy reference. Just as typists eventually memorize the QWERTY (oe AZERTY, etc.) keyboard layout, most APL'ers quickly memorize APL keyboard layouts. A printed keyboard reference is good to keep however, if only for some of the lesser used APL symbols. Several frequently used APL symbols are very easily keyboard-memorized: ∊ (epsilon = Alt-e), ⍴ (rho = Alt-r), ∼ (tilde = Alt-t) and ⍳ (iota = Alt-i) since the beginning letter of the symbol is same-placed as its qwerty letter equivalent in the alphabet. Also, all of the APL symbols may be found (and copied to the current session or function being edited) from the Language Bar at the top of the APL session window. Cross ref. wiki page Keyboard and Language bar.
Even if you have an APL font installed, that may not be the end of the story. Each font designer decides what glyphs to display and for which characters. Also, some implementations of supposedly Unicode fonts don't always display the same glyphs in the same places or in the same way. The SimPL Medium font, which comes with NARS2000, will display some characters with different glyphs than are displayed by the font APL385 Unicode. For example, these are the underlined letters A to Z, which are valid identifiers in APL: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z. Now, to display these characters in APL385 Unicode, the characters use code positions 9398 through 9423, or 0x24B6 through 0x24CF, which show up as Ⓐ Ⓑ Ⓒ Ⓓ Ⓔ Ⓕ Ⓖ Ⓗ Ⓘ Ⓙ Ⓚ Ⓛ Ⓜ Ⓝ Ⓞ Ⓟ Ⓠ Ⓡ Ⓢ Ⓣ Ⓤ Ⓥ Ⓦ Ⓧ Ⓨ Ⓩ, which, while not the same, is very close. When copying underlined APL characters to the clipboard, you may convert them to lowercase by first setting the user preference "Underbar alphabet converted to lowercase".
The standard Arial font doesn't even have a built-in set of underlined characters, nor does SimPL. (Yet note some glyphs, as shown below, that are used by NARS2000, are not present in APL385.)
Also, the settings for Unicode for APL symbols, which are listed as being 0x2300 - 0x23F3, do not necessarily appear - or appear the same - in all APL fonts.
Extra APL Glyphs
While any Unicode APL font will display all of the standard APL glyphs, NARS2000 uses (or has plans to use) some extra glyphs not found in all Unicode APL fonts such as
|Section||§||167 or U+00A7||Alt-S||Multiset Symmetric Difference|
|Pi||π||960 or U+03C0||Alt-p||Prime Decomposition and Number-theoretic|
|Double-Shriek||‼||8252 or U+203C||Alt-k||Combinatorial Operator|
|NaN||∅||8709 or U+2205||Alt-5||NaN|
|Root||√||8730 or U+221A||Alt-R||Square Root and Nth Root|
|Infinity||∞||8734 or U+221E||Alt-f||Infinity|
|Mismatch||≢||8802 or U+2262||Alt-@||Mismatch|
|Left-shoe-underbar||⊆||8838 or U+2286||Alt-Z||Subset of|
|Right-shoe-underbar||⊇||8839 or U+2287||Alt-X||Superset of|
|Circle-middle-dot||⊙||8857 or U+2299||Alt-?||Null operator|
|Quad-colon||⍠||9056 or U+2360||Alt-_||Variant operator|
|Dieresis-downtack||⍡||9057 or U+2361||Alt-N||Convolution operator|
|Dieresis-del||⍢||9058 or U+2362||Alt-G||Dual operator†|
|Dieresis-star||⍣||9059 or U+2363||Alt-P||Power operator†|
|Dieresis-jot||⍤||9060 or U+2364||Alt-J||Rank operator|
|Dieresis-circle||⍥||9061 or U+2365||Alt-O||Composition operator|
|Down-shoe-stile||⍦||9062 or U+2366||Alt-m||Multiset operator|
|Dieresis-tilde||⍨||9064 or U+2368||Alt-T||Commute operator|
|Del-tilde||⍫||9067 or U+236B||Alt-k||Commutator operator†|
|Zilde||⍬||9068 or U+236C||Alt-}||Empty simple numeric vector|
|Stile-tilde||⍭||9069 or U+236D||Alt-M||Partition operator†|
† = Not currently implemented.
All of the above glyphs may be found in SImPL medium, all but the Infinity symbol in SImPL, and all but the Null operator in APL385 Unicode.