s/node/client; mention restart is needed

docs/convergence-secret.rst

@@ -5,16 +5,16 @@ What Is It?
 
 The identifer of a file (also called the "capability" to a file) is derived
 from two pieces of information when the file is uploaded: the content of the
-file and the upload node's "convergence secret". By default, the convergence
-secret is randomly generated by the node when it first starts up, then stored
-in the node's base directory (<Tahoe's node dir>/private/convergence) and
-re-used after that. So the same file content uploaded from the same node will
-always have the same cap. Uploading the file from a different node with a
-different convergence secret would result in a different cap—and in a second
-copy of the file's contents stored on the grid. If you want files you upload
-to converge (also known as "deduplicate") with files uploaded by someone
-else, just make sure you're using the same convergence secret when you upload
-files as they
+file and the upload client's "convergence secret". By default, the
+convergence secret is randomly generated by the client when it first starts
+up, then stored in the client's base directory (<Tahoe's node
+dir>/private/convergence) and re-used after that. So the same file content
+uploaded from the same client will always have the same cap. Uploading the
+file from a different client with a different convergence secret would result
+in a different cap—and in a second copy of the file's contents stored on the
+grid. If you want files you upload to converge (also known as "deduplicate")
+with files uploaded by someone else, just make sure you're using the same
+convergence secret when you upload files as they
 
 The advantages of deduplication should be clear, but keep in mind that the
 convergence secret was created to protect confidentiality. There are two
@@ -54,8 +54,8 @@ All your old file capabilities will still work, but the new data that you
 upload will not be deduplicated with the old data. If you upload all of the
 same things to the grid, you will end up using twice the space until garbage
 collection kicks in (if it's enabled). Changing the convergence secret that a
-node uses for uploads can be though of as moving the node to a new
-"deduplication domain".
+storage client uses for uploads can be though of as moving the client to a
+new "deduplication domain".
 
 How To Use It
 -------------
@@ -69,7 +69,10 @@ scp installed, run:
   *scp ~/.tahoe/private/convergence
   my_other_account@B:.tahoe/private/convergence*
 
-If you have two different nodes on a single computer, say one for each disk,
-you would do:
+If you have two different clients on a single computer, say one for each
+disk, you would do:
 
   *cp /tahoe1/private/convergence /tahoe2/private/convergence*
+
+After you change the convergence secret file, you must restart the client
+before it will stop using the old one and read the new one from the file.