diff --git a/entries/Plan 9.txt b/entries/Plan 9.txt
index 51f5843..3f24304 100644
--- a/entries/Plan 9.txt	
+++ b/entries/Plan 9.txt	
@@ -4,8 +4,7 @@ n. In the late 1980s, researchers at Bell Labs (especially Rob Pike of
 Kernighan Pike fame) got bored with the limitations of UNIX and decided to
 reimplement the entire system. The result was called Plan 9 in the Bell Labs
 tradition of selecting names that make marketeers wince. The developers also
-wished to pay homage to the famous film, Plan 9 From Outer Space ,
+wished to pay homage to the famous film, Plan 9 From Outer Space,
 considered by some to be the worst movie ever made. The source is available
 for download under open-source terms. The developers and a small fan base
 hang out at comp.os.
-
diff --git a/entries/model_m.txt b/entries/model_m.txt
new file mode 100644
index 0000000..ebea998
--- /dev/null
+++ b/entries/model_m.txt
@@ -0,0 +1,18 @@
+model m
+
+A type of mechanical keyboard originally made by IBM for the early generation
+of PCs in the 1980s. These keyboards are known for their novel use of buckling
+springs rather than microswitches and metal backplate which gives them a
+distinctive typing sound. The design was sold to a company named Unicomp in
+the 1990s and these keyboards are still manufactured.
+
+The model M keyboard (either original or Unicomp versions) are popular with
+hackers who enjoy the historical connection to early personal computers,
+the build quality and the ease of key removal and cleaning. Since a
+hacker's main tool is their keyboard it's worth investing in something
+durable and ergonomic.
+
+On some older model M keyboards the plastic rivets holding the metal
+backplate on become brittle and fall off. These can be replaced using
+standard tools in a procedure known as a "bolt job". Such repairability
+is rare for a modern keyboard.
\ No newline at end of file
diff --git a/entries/pessimal.txt b/entries/pessimal.txt
index eb73757..81167e8 100644
--- a/entries/pessimal.txt
+++ b/entries/pessimal.txt
@@ -2,7 +2,6 @@ pessimal
 
 /pesiml/ , adj. [Latin-based antonym for optimal ] Maximally bad. This is a
 pessimal situation. Also pessimize vt. To make as bad as possible. These
-words are the obvious Latin-based antonyms for optimal and optimize , but
+words are the obvious Latin-based antonyms for optimal and optimize, but
 for some reason they do not appear in most English dictionaries, although
 pessimize is listed in the OED.
-