diff --git a/external-latency.rkt b/external-latency.rkt
index df0fecf..3ca8c2c 100644
--- a/external-latency.rkt
+++ b/external-latency.rkt
@@ -35,6 +35,7 @@
                (set! server-variation 'syndicate-js)]
 	      ["--racket" "use threaded racket server" (set! server-variation 'racket)]
 	      ["--racket-evt" "use evented racket server" (set! server-variation 'racket-evt)]
+	      ["--racket-semi-threaded" "use semi-threaded racket server" (set! server-variation 'racket-semi-threaded)]
 	      ["--other" name "use other server" (set! server-variation name)])
 
 (when (not server-variation)
@@ -74,6 +75,7 @@
      ['imperative-syndicate+tcp (format-racket-server-command-line "echo-server-imperative-syndicate-tcp-driver.rkt")]
      ['racket (format-racket-server-command-line "plain-racket-server.rkt")]
      ['racket-evt (format-racket-server-command-line "plain-racket-server-evt.rkt")]
+     ['racket-semi-threaded (format-racket-server-command-line "plain-racket-server-semi-threaded.rkt")]
      ['erlang
       (define erlang-version-command
 	"erl -noshell -eval 'io:format(erlang:system_info(otp_release)), halt().'")
diff --git a/plain-racket-server-semi-threaded.rkt b/plain-racket-server-semi-threaded.rkt
new file mode 100644
index 0000000..eaeca64
--- /dev/null
+++ b/plain-racket-server-semi-threaded.rkt
@@ -0,0 +1,74 @@
+#lang racket/base
+
+(require racket/match)
+(require racket/tcp)
+(require racket/port)
+(require logbook)
+(require racket/cmdline)
+
+(define server-entry-name #f)
+(define server-entry-type #f)
+
+(command-line #:program "plain-racket-server-semi-threaded.rkt"
+	      #:once-each
+	      ["--logbook-entry-name" name
+	       "set logbook entry name to use when recording run statistics"
+	       (set! server-entry-name name)]
+	      ["--logbook-entry-type" type
+	       "set logbook entry type to use"
+	       (set! server-entry-type type)])
+
+(when (not server-entry-type)
+  (error 'plain-racket-server "Please supply the --logbook-entry-type command-line argument."))
+
+(define L (default-logbook))
+(define E (logbook-entry L "minimart" server-entry-name server-entry-type))
+(define Tmem (logbook-table E "server-memory-use" #:column-spec '(time-seconds memory-use)))
+(define Tconn (logbook-table E "server-connections" #:column-spec '(time-seconds connection-count)))
+
+(define connection-count 0)
+(define first-connection-seen? #f)
+
+(define statistics-poll-interval 2000)
+
+(void (thread
+       (lambda ()
+	 (let loop ()
+	   (sleep (/ statistics-poll-interval 1000.0))
+	   (printf "~a connections\n" connection-count)
+	   (flush-output)
+	   (define now (current-inexact-milliseconds))
+	   (write-logbook-datum! Tmem (list (/ now 1000.0) (current-memory-use)))
+	   (write-logbook-datum! Tconn (list (/ now 1000.0) connection-count))
+	   (when (and first-connection-seen? (zero? connection-count))
+             (close-logbook L)
+	     (exit 0))
+	   (loop)))))
+
+(define (connection in out)
+  (set! connection-count (+ connection-count 1))
+  (set! first-connection-seen? #t)
+  (thread
+   (lambda ()
+     (let loop ()
+       (sync (handle-evt (read-line-evt in 'any)
+                         (match-lambda
+                           [(? eof-object?)
+                            (close-input-port in)
+                            (close-output-port out)
+                            (set! connection-count (- connection-count 1))]
+                           [line
+                            (fprintf out "~a\n" line)
+                            (flush-output out)
+                            (loop)])))))))
+
+(define (listener port-number)
+  (define s (tcp-listen port-number 128 #t))
+  (let loop ()
+    (sync (handle-evt (tcp-accept-evt s)
+                      (lambda (item)
+                        (match-define (list in out) item)
+                        (connection in out)
+                        (loop))))))
+
+(listener 5999)