diff --git a/mps/manual/source/guide/overview.rst b/mps/manual/source/guide/overview.rst
index 8b9789d2289..0b32c0e6a7a 100644
--- a/mps/manual/source/guide/overview.rst
+++ b/mps/manual/source/guide/overview.rst
@@ -47,13 +47,13 @@ Supported target platforms
 
 The MPS is currently supported for deployment on:
 
-- Windows XP or later, both 32- and 64-bit;
+- Windows XP or later on IA-32 and x86-64, using Microsoft Visual C/C++;
 
-- Linux (Ubuntu 11 and RHEL 6.3 known good, otherwise YMMV);
+- Linux (Ubuntu 11 and RHEL 6.3 known good, otherwise YMMV) on IA-32 and x86-64, using GCC;
 
-- FreeBSD 7 or later on IA-32 and x86-64;
+- FreeBSD 7 or later, on IA-32 and x86-64, using GCC;
 
-- Mac OS X 10.4 or later on IA-32 and x86-64 (single threaded only).
+- Mac OS X 10.4 or later, on IA-32 and x86-64 (single threaded only), using Clang/LLVM.
 
 The MPS will *not* work in a multi-threaded 32-bit application on 64-bit
 Windows 7.  This is due to a serious fault in Microsoft's WOW64 emulator
diff --git a/mps/manual/source/topic/allocation.rst b/mps/manual/source/topic/allocation.rst
index 0f13c54181a..93d2b95060f 100644
--- a/mps/manual/source/topic/allocation.rst
+++ b/mps/manual/source/topic/allocation.rst
@@ -406,8 +406,9 @@ Before calling :c:func:`mps_commit`:
 
 You do not have to initialize the whole block so long as you satisfy
 these conditions. For example, it is permissible to defer
-initialization completely by writing ``TYPE_UNINITIALIZED`` into a
-tag field, so long as you handle this correctly in the format methods.
+initialization completely (for example, by writing
+``TYPE_UNINITIALIZED`` into a tag field), so long as you handle this
+correctly in the format methods.
 
 However, if you do not initialize the whole block then you should
 beware: the uninitialized contents of the block is likely to consist
diff --git a/mps/manual/source/topic/platform.rst b/mps/manual/source/topic/platform.rst
index ccb67a229ee..f1de7e9f648 100644
--- a/mps/manual/source/topic/platform.rst
+++ b/mps/manual/source/topic/platform.rst
@@ -298,8 +298,8 @@ Formerly supported compiler toolchains:
 
 .. note::
 
-    .. [1] Obsolete, from when there was an important distinction the 80386
-           and 80486 processors.
+    .. [1] Obsolete: the MPS used to make a distinction between the
+           80386 and 80486 processor architectures.
 
     .. [2] This was the MIPSpro C compiler on IRIX; and the Digital C
            Compiler on OSF/1.
@@ -341,7 +341,7 @@ Platform    Status
 ``w3i3m9``  *Not supported*
 ``w3i3mv``  Supported
 ``w3i6mv``  Supported
-``w3ppmv``  *Not Supported*
+``w3ppmv``  *Not supported*
 ``xci3gc``  *Not supported*
 ``xci3ll``  Supported
 ``xci6ll``  Supported
diff --git a/mps/readme.txt b/mps/readme.txt
index b4f92d455cf..9d2237cc106 100644
--- a/mps/readme.txt
+++ b/mps/readme.txt
@@ -66,13 +66,13 @@ Supported target platforms
 
 The MPS is currently supported for deployment on:
 
-- Windows XP or later, both 32- and 64-bit;
+- Windows XP or later on IA-32 and x86-64, using Microsoft Visual C/C++;
 
-- Linux (Ubuntu 11 and RHEL 6.3 known good, otherwise YMMV);
+- Linux (Ubuntu 11 and RHEL 6.3 known good, otherwise YMMV) on IA-32 and x86-64, using GCC;
 
-- FreeBSD 7 or later on IA-32 and x86-64;
+- FreeBSD 7 or later, on IA-32 and x86-64, using GCC;
 
-- Mac OS X 10.4 or later on IA-32 and x86-64 (single threaded only).
+- Mac OS X 10.4 or later, on IA-32 and x86-64 (single threaded only), using Clang/LLVM.
 
 The MPS will *not* work in a multi-threaded 32-bit application on 64-bit
 Windows 7.  This is due to a serious fault in Microsoft's WOW64 emulator