diff --git a/applications/test/memInfo/Make/files b/applications/test/memInfo/Make/files
index c42564e8fc..1c9d3fff8e 100644
--- a/applications/test/memInfo/Make/files
+++ b/applications/test/memInfo/Make/files
@@ -1,3 +1,3 @@
-memInfo.C
+Test-memInfo.C
 
-EXE = $(FOAM_USER_APPBIN)/memInfo
+EXE = $(FOAM_USER_APPBIN)/Test-memInfo
diff --git a/applications/test/memInfo/Test-memInfo.C b/applications/test/memInfo/Test-memInfo.C
new file mode 100644
index 0000000000..0eb32803c8
--- /dev/null
+++ b/applications/test/memInfo/Test-memInfo.C
@@ -0,0 +1,61 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2010-2010 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Application
+
+Description
+
+\*---------------------------------------------------------------------------*/
+
+#include "memInfo.H"
+#include "IOstreams.H"
+#include "List.H"
+#include "vector.H"
+
+using namespace Foam;
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+//  Main program:
+
+int main(int argc, char *argv[])
+{
+    const int n = 10000000;
+    const char* const memTags = "peak/size/rss mem: ";
+
+    memInfo mem;
+
+    Info<< memTags << mem << endl;
+    List<vector> lst(n, vector::one);
+
+    Info<< "allocate " << n << " vectors" << nl
+        << memTags << mem.update() << endl;
+
+    lst.clear();
+    Info<< "clear" << nl
+        << memTags << mem.update() << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //
diff --git a/applications/test/memInfo/memInfo.C b/applications/test/memInfo/memInfo.C
deleted file mode 100644
index fb20be6d8d..0000000000
--- a/applications/test/memInfo/memInfo.C
+++ /dev/null
@@ -1,19 +0,0 @@
-#include "memInfo.H"
-#include "IOstreams.H"
-#include "List.H"
-#include "vector.H"
-
-using namespace Foam;
-
-int main()
-{
-    memInfo m;
-
-    Info<< m << endl;
-
-    List<vector> l(10000000, vector::one);
-
-    Info<< m.update() << endl;
-
-    return 0;
-}
diff --git a/src/OSspecific/POSIX/memInfo/memInfo.C b/src/OSspecific/POSIX/memInfo/memInfo.C
index ef76fe004f..0d593ee4df 100644
--- a/src/OSspecific/POSIX/memInfo/memInfo.C
+++ b/src/OSspecific/POSIX/memInfo/memInfo.C
@@ -47,6 +47,8 @@ Foam::memInfo::~memInfo()
 
 const Foam::memInfo& Foam::memInfo::update()
 {
+    // reset to invalid values first
+    peak_ = size_ = rss_ = -1;
     IFstream is("/proc/" + name(pid()) + "/status");
 
     while (is.good())
diff --git a/src/OSspecific/POSIX/memInfo/memInfo.H b/src/OSspecific/POSIX/memInfo/memInfo.H
index 73f614fea7..25f29b0164 100644
--- a/src/OSspecific/POSIX/memInfo/memInfo.H
+++ b/src/OSspecific/POSIX/memInfo/memInfo.H
@@ -27,6 +27,9 @@ Class
 Description
     Memory usage information for the process running this object.
 
+Note
+    Uses the information from /proc/\<pid\>/status
+
 SourceFiles
     memInfo.C
 
@@ -52,13 +55,13 @@ class memInfo
 {
     // Private data
 
-        //- Peak memory used by the process (VmPeak in /proc/<pid>/status)
+        //- Peak memory used by the process (VmPeak in /proc/\<pid\>/status)
         int peak_;
 
-        //- Memory used by the process (VmSize in /proc/<pid>/status)
+        //- Memory used by the process (VmSize in /proc/\<pid\>/status)
         int size_;
 
-        //- Resident set size of the process (VmRSS in /proc/<pid>/status)
+        //- Resident set size of the process (VmRSS in /proc/\<pid\>/status)
         int rss_;
 
 
@@ -76,24 +79,27 @@ public:
 
     // Member Functions
 
-        //- Parse /proc/<pid>/status
+        //- Parse /proc/\<pid\>/status
         const memInfo& update();
 
         // Access
 
-            //- Access the stored peak memory
+            //- Access the stored peak memory (VmPeak in /proc/\<pid\>/status)
+            //  The value is stored from the previous update()
             int peak() const
             {
                 return peak_;
             }
 
-            //- Access the stored memory size
+            //- Access the stored memory size (VmSize in /proc/\<pid\>/status)
+            //  The value is stored from the previous update()
             int size() const
             {
                 return size_;
             }
 
-            //- Access the stored rss value
+            //- Access the stored rss value (VmRSS in /proc/\<pid\>/status)
+            //  The value is stored from the previous update()
             int rss() const
             {
                 return rss_;
@@ -102,7 +108,10 @@ public:
 
     // IOstream Operators
 
+        //- Read peak/size/rss from stream
         friend Istream& operator>>(Istream&, memInfo&);
+
+        //- Write peak/size/rss to stream
         friend Ostream& operator<<(Ostream&, const memInfo&);
 };