diff --git a/basis/byte-vectors/byte-vectors-docs.factor b/basis/byte-vectors/byte-vectors-docs.factor
new file mode 100644
index 0000000000..3873f73bfe
--- /dev/null
+++ b/basis/byte-vectors/byte-vectors-docs.factor
@@ -0,0 +1,37 @@
+USING: arrays byte-arrays help.markup help.syntax kernel
+byte-vectors.private combinators ;
+IN: byte-vectors
+
+ARTICLE: "byte-vectors" "Byte vectors"
+"A byte vector is a resizable mutable sequence of unsigned bytes. Byte vector words are found in the " { $vocab-link "byte-vectors" } " vocabulary."
+$nl
+"Byte vectors form a class:"
+{ $subsection byte-vector }
+{ $subsection byte-vector? }
+"Creating byte vectors:"
+{ $subsection >byte-vector }
+{ $subsection <byte-vector> }
+"Literal syntax:"
+{ $subsection POSTPONE: BV{ }
+"If you don't care about initial capacity, a more elegant way to create a new byte vector is to write:"
+{ $code "BV{ } clone" } ;
+
+ABOUT: "byte-vectors"
+
+HELP: byte-vector
+{ $description "The class of resizable byte vectors. See " { $link "byte-vectors" } " for information." } ;
+
+HELP: <byte-vector>
+{ $values { "n" "a positive integer specifying initial capacity" } { "byte-vector" byte-vector } }
+{ $description "Creates a new byte vector that can hold " { $snippet "n" } " bytes before resizing." } ;
+
+HELP: >byte-vector
+{ $values { "seq" "a sequence" } { "byte-vector" byte-vector } }
+{ $description "Outputs a freshly-allocated byte vector with the same elements as a given sequence." }
+{ $errors "Throws an error if the sequence contains elements other than integers." } ;
+
+HELP: BV{
+{ $syntax "BV{ elements... }" }
+{ $values { "elements" "a list of bytes" } }
+{ $description "Marks the beginning of a literal byte vector. Literal byte vectors are terminated by " { $link POSTPONE: } } "." } 
+{ $examples { $code "BV{ 1 2 3 12 }" } } ;
diff --git a/basis/byte-vectors/byte-vectors-tests.factor b/basis/byte-vectors/byte-vectors-tests.factor
new file mode 100644
index 0000000000..9a100d9795
--- /dev/null
+++ b/basis/byte-vectors/byte-vectors-tests.factor
@@ -0,0 +1,17 @@
+IN: byte-vectors.tests
+USING: tools.test byte-vectors vectors sequences kernel
+prettyprint ;
+
+[ 0 ] [ 123 <byte-vector> length ] unit-test
+
+: do-it
+    123 [ over push ] each ;
+
+[ t ] [
+    3 <byte-vector> do-it
+    3 <vector> do-it sequence=
+] unit-test
+
+[ t ] [ BV{ } byte-vector? ] unit-test
+
+[ "BV{ }" ] [ BV{ } unparse ] unit-test
diff --git a/basis/byte-vectors/byte-vectors.factor b/basis/byte-vectors/byte-vectors.factor
new file mode 100644
index 0000000000..b2c0d55c0f
--- /dev/null
+++ b/basis/byte-vectors/byte-vectors.factor
@@ -0,0 +1,51 @@
+! Copyright (C) 2008 Slava Pestov.
+! See http://factorcode.org/license.txt for BSD license.
+USING: arrays kernel kernel.private math sequences
+sequences.private growable byte-arrays accessors parser
+prettyprint.backend ;
+IN: byte-vectors
+
+TUPLE: byte-vector
+{ underlying byte-array }
+{ length array-capacity } ;
+
+: <byte-vector> ( n -- byte-vector )
+    <byte-array> 0 byte-vector boa ; inline
+
+: >byte-vector ( seq -- byte-vector )
+    T{ byte-vector f B{ } 0 } clone-like ;
+
+M: byte-vector like
+    drop dup byte-vector? [
+        dup byte-array?
+        [ dup length byte-vector boa ] [ >byte-vector ] if
+    ] unless ;
+
+M: byte-vector new-sequence
+    drop [ <byte-array> ] [ >fixnum ] bi byte-vector boa ;
+
+M: byte-vector equal?
+    over byte-vector? [ sequence= ] [ 2drop f ] if ;
+
+M: byte-array like
+    #! If we have an byte-array, we're done.
+    #! If we have a byte-vector, and it's at full capacity,
+    #! we're done. Otherwise, call resize-byte-array, which is a
+    #! relatively fast primitive.
+    drop dup byte-array? [
+        dup byte-vector? [
+            [ length ] [ underlying>> ] bi
+            2dup length eq?
+            [ nip ] [ resize-byte-array ] if
+        ] [ >byte-array ] if
+    ] unless ;
+
+M: byte-array new-resizable drop <byte-vector> ;
+
+: BV{ \ } [ >byte-vector ] parse-literal ; parsing
+
+M: byte-vector pprint* pprint-object ;
+M: byte-vector pprint-delims drop \ BV{ \ } ;
+M: byte-vector >pprint-sequence ;
+
+INSTANCE: byte-vector growable
diff --git a/basis/byte-vectors/summary.txt b/basis/byte-vectors/summary.txt
new file mode 100644
index 0000000000..e914ebb319
--- /dev/null
+++ b/basis/byte-vectors/summary.txt
@@ -0,0 +1 @@
+Growable byte arrays
diff --git a/basis/byte-vectors/tags.txt b/basis/byte-vectors/tags.txt
new file mode 100644
index 0000000000..42d711b32b
--- /dev/null
+++ b/basis/byte-vectors/tags.txt
@@ -0,0 +1 @@
+collections
diff --git a/basis/io/streams/byte-array/byte-array-docs.factor b/basis/io/streams/byte-array/byte-array-docs.factor
new file mode 100644
index 0000000000..7b27621343
--- /dev/null
+++ b/basis/io/streams/byte-array/byte-array-docs.factor
@@ -0,0 +1,34 @@
+USING: help.syntax help.markup io byte-arrays quotations ;
+IN: io.streams.byte-array
+
+ABOUT: "io.streams.byte-array"
+
+ARTICLE: "io.streams.byte-array" "Byte-array streams"
+"Byte array streams:"
+{ $subsection <byte-reader> }
+{ $subsection <byte-writer> }
+"Utility combinators:"
+{ $subsection with-byte-reader }
+{ $subsection with-byte-writer } ;
+
+HELP: <byte-reader>
+{ $values { "byte-array" byte-array }
+    { "encoding" "an encoding descriptor" }
+    { "stream" "a new byte reader" } }
+{ $description "Creates an input stream reading from a byte array using an encoding." } ;
+
+HELP: <byte-writer>
+{ $values { "encoding" "an encoding descriptor" }
+    { "stream" "a new byte writer" } }
+{ $description "Creates an output stream writing data to a byte array using an encoding." } ;
+
+HELP: with-byte-reader
+{ $values { "encoding" "an encoding descriptor" }
+    { "quot" quotation } { "byte-array" byte-array } }
+{ $description "Calls the quotation in a new dynamic scope with " { $link input-stream } " rebound to an input stream for reading from a byte array using an encoding." } ;
+
+HELP: with-byte-writer
+{ $values  { "encoding" "an encoding descriptor" }
+    { "quot" quotation }
+    { "byte-array" byte-array } }
+{ $description "Calls the quotation in a new dynamic scope with " { $link output-stream } " rebound to an output stream writing data to a byte array using an encoding." } ;
diff --git a/basis/io/streams/byte-array/byte-array-tests.factor b/basis/io/streams/byte-array/byte-array-tests.factor
new file mode 100644
index 0000000000..77a9126740
--- /dev/null
+++ b/basis/io/streams/byte-array/byte-array-tests.factor
@@ -0,0 +1,9 @@
+USING: tools.test io.streams.byte-array io.encodings.binary
+io.encodings.utf8 io kernel arrays strings ;
+
+[ B{ 1 2 3 } ] [ binary [ { 1 2 3 } write ] with-byte-writer ] unit-test
+[ B{ 1 2 3 } ] [ { 1 2 3 } binary [ 3 read ] with-byte-reader ] unit-test
+
+[ B{ BIN: 11110101 BIN: 10111111 BIN: 10000000 BIN: 10111111 BIN: 11101111 BIN: 10000000 BIN: 10111111 BIN: 11011111 BIN: 10000000 CHAR: x } ]
+[ { BIN: 101111111000000111111 BIN: 1111000000111111 BIN: 11111000000 CHAR: x } utf8 [ write ] with-byte-writer ] unit-test
+[ { BIN: 101111111000000111111 } t ] [ { BIN: 11110101 BIN: 10111111 BIN: 10000000 BIN: 10111111 } utf8 <byte-reader> contents dup >array swap string? ] unit-test
diff --git a/basis/io/streams/byte-array/byte-array.factor b/basis/io/streams/byte-array/byte-array.factor
new file mode 100644
index 0000000000..9d89c3d814
--- /dev/null
+++ b/basis/io/streams/byte-array/byte-array.factor
@@ -0,0 +1,16 @@
+USING: byte-arrays byte-vectors kernel io.encodings io.streams.string
+sequences io namespaces io.encodings.private accessors ;
+IN: io.streams.byte-array
+
+: <byte-writer> ( encoding -- stream )
+    512 <byte-vector> swap <encoder> ;
+
+: with-byte-writer ( encoding quot -- byte-array )
+    [ <byte-writer> ] dip [ output-stream get ] compose with-output-stream*
+    dup encoder? [ stream>> ] when >byte-array ; inline
+
+: <byte-reader> ( byte-array encoding -- stream )
+    [ >byte-vector dup reverse-here ] dip <decoder> ;
+
+: with-byte-reader ( byte-array encoding quot -- )
+    [ <byte-reader> ] dip with-input-stream* ; inline
diff --git a/basis/ui/freetype/freetype.factor b/basis/ui/freetype/freetype.factor
index 6c0eaaa9ac..22a4f1722d 100644
--- a/basis/ui/freetype/freetype.factor
+++ b/basis/ui/freetype/freetype.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2005, 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: alien alien.accessors alien.c-types arrays io kernel libc
-math math.vectors namespaces opengl opengl.gl prettyprint assocs
+math math.vectors namespaces opengl opengl.gl assocs
 sequences io.files io.styles continuations freetype
 ui.gadgets.worlds ui.render ui.backend byte-arrays accessors
 locals specialized-arrays.direct.uchar ;
diff --git a/basis/ui/gadgets/labelled/labelled.factor b/basis/ui/gadgets/labelled/labelled.factor
index 108c5ae461..636e25cea5 100644
--- a/basis/ui/gadgets/labelled/labelled.factor
+++ b/basis/ui/gadgets/labelled/labelled.factor
@@ -3,7 +3,7 @@
 USING: arrays ui.gadgets.buttons ui.gadgets.borders
 ui.gadgets.labels ui.gadgets.panes ui.gadgets.scrollers
 ui.gadgets.tracks ui.gadgets.theme ui.gadgets.frames
-ui.gadgets.grids io kernel math models namespaces prettyprint
+ui.gadgets.grids io kernel math models namespaces
 sequences sequences words classes.tuple ui.gadgets ui.render
 colors accessors ;
 IN: ui.gadgets.labelled
diff --git a/basis/ui/gadgets/presentations/presentations.factor b/basis/ui/gadgets/presentations/presentations.factor
index 33ef3bbe3a..61a55e926b 100644
--- a/basis/ui/gadgets/presentations/presentations.factor
+++ b/basis/ui/gadgets/presentations/presentations.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2005, 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: arrays accessors definitions hashtables io kernel
-prettyprint sequences strings io.styles words help math models
+sequences strings io.styles words help math models
 namespaces quotations
 ui.gadgets ui.gadgets.borders ui.gadgets.buttons
 ui.gadgets.labels ui.gadgets.menus ui.gadgets.worlds
diff --git a/basis/ui/gadgets/worlds/worlds.factor b/basis/ui/gadgets/worlds/worlds.factor
index 68a2a18210..3b9b2fa1f3 100644
--- a/basis/ui/gadgets/worlds/worlds.factor
+++ b/basis/ui/gadgets/worlds/worlds.factor
@@ -3,7 +3,7 @@
 USING: accessors arrays assocs continuations kernel math models
 namespaces opengl sequences io combinators fry math.vectors
 ui.gadgets ui.gestures ui.render ui.backend ui.gadgets.tracks
-debugger math.geometry.rect ;
+math.geometry.rect ;
 IN: ui.gadgets.worlds
 
 TUPLE: world < track
@@ -76,7 +76,7 @@ C: <world-error> world-error
 SYMBOL: ui-error-hook
 
 : ui-error ( error -- )
-    ui-error-hook get [ call ] [ print-error ] if* ;
+    ui-error-hook get [ call ] [ die ] if* ;
 
 ui-error-hook global [ [ rethrow ] or ] change-at
 
diff --git a/basis/ui/ui.factor b/basis/ui/ui.factor
index de2eb71307..88f0a353b9 100644
--- a/basis/ui/ui.factor
+++ b/basis/ui/ui.factor
@@ -1,10 +1,10 @@
 ! Copyright (C) 2006, 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: arrays assocs io kernel math models namespaces make
-prettyprint dlists deques sequences threads sequences words
-debugger ui.gadgets ui.gadgets.worlds ui.gadgets.tracks
-ui.gestures ui.backend ui.render continuations init combinators
-hashtables concurrency.flags sets accessors calendar ;
+dlists deques sequences threads sequences words ui.gadgets
+ui.gadgets.worlds ui.gadgets.tracks ui.gestures ui.backend
+ui.render continuations init combinators hashtables
+concurrency.flags sets accessors calendar ;
 IN: ui
 
 ! Assoc mapping aliens to gadgets
diff --git a/basis/ui/x11/x11.factor b/basis/ui/x11/x11.factor
index b65236d1f9..a532a13b69 100755
--- a/basis/ui/x11/x11.factor
+++ b/basis/ui/x11/x11.factor
@@ -5,7 +5,7 @@ ui.gestures ui.backend ui.clipboards ui.gadgets.worlds ui.render
 assocs kernel math namespaces opengl sequences strings x11.xlib
 x11.events x11.xim x11.glx x11.clipboard x11.constants
 x11.windows io.encodings.string io.encodings.ascii
-io.encodings.utf8 combinators debugger command-line qualified
+io.encodings.utf8 combinators command-line qualified
 math.vectors classes.tuple opengl.gl threads math.geometry.rect
 environment ascii ;
 IN: ui.x11