--- a/slideshow.tex	Tue Jan 15 02:49:44 2008 -0500
+++ b/slideshow.tex	Tue Jan 15 03:03:10 2008 -0500
@@ -117,16 +117,33 @@
 	}
 \end{slide}}
 
-\overlays{7}{
-\begin{slide}{?. Channels}
+\overlays{6}{
+\begin{slide}{?. Channels - Connections}
 	\begin{tabular}{ll}
 	\begin{minipage}{2.5in}
 		\begin{itemstep}
-			\item Devices are attached to ``channels''
+			\item A device is attached to a Control Unit
+			\item Control Units are connected to...
 			\begin{itemstep}
-				\item Technically they are subchannels
+				\item Storage
+				\item CPUs
 			\end{itemstep}
-			\item Save channel commands in storage
+			\item \emph{Logical} link between a device and CPU is a \emph{subchannel}
+			\item \emph{Physical} connections are a lot more complex
+		\end{itemstep}
+	\end{minipage} & 
+	\begin{minipage}{2in}
+		\begin{center}\includegraphics[height=2.5in]{channels.eps}\end{center}
+	\end{minipage}\\
+	\end{tabular}
+\end{slide}}
+
+\overlays{5}{
+\begin{slide}{?. Channels - Issuing I/O}
+	\begin{tabular}{ll}
+	\begin{minipage}{2.5in}
+		\begin{itemstep}
+			\item Save Channel Command Words (CCWs) in storage
 			\item Signal CU to execute stored commands
 			\item CU generates an IO interrupt when...
 			\begin{itemstep}
@@ -141,48 +158,40 @@
 	\end{tabular}
 \end{slide}}
 
-\overlays{4}{
-\begin{slide}{?. Channels}
+\overlays{7}{
+\begin{slide}{?. Channels - CCWs}
 	\begin{center}\includegraphics[height=1in]{ccw.eps}\end{center}
-	\vspace*{4mm}
 
-	\begin{tabular}{ll}
-	\begin{minipage}{2.2in}
-		\begin{itemstep}
-			\item Command
-			\item Flags
-			\item Byte count
-			\item Buffer address
-		\end{itemstep}
-		\vspace*{1.1cm}
-	\end{minipage} &
-	\begin{minipage}{2in}
-		\onlySlide*{1}{
-			\begin{itemize}
-				\item Commands
-				\begin{itemize}
-					\item Write
-					\item Read
-					\item Read Backward
-					\item Control
-					\item Sense
-					\item Sense ID
-				\end{itemize}
-			\end{itemize}
+	\fromSlide*{2}{
+	\begin{itemize}
+		\item Command
+		\onlySlide*{3}{
+		\begin{itemize}
+			\item Write
+			\item Read
+			\item Read Backward
+			\item Control
+			\item Sense
+			\item Sense ID
+			\item Transfer in Control (branch!)
+		\end{itemize}
 		}
-		\onlySlide*{2}{
-			\begin{itemize}
-				\item Flags
-				\begin{itemize}
-					\item CCWs chaining
-					\item Skip (do not read)
-					\item Indirect addressing
-					\item Suspend execution
-				\end{itemize}
-			\end{itemize}
+
+		\fromSlide*{4}{\item Flags}
+		\onlySlide*{5}{
+		\begin{itemize}
+			\item CCWs chaining
+			\item Skip (do not read)
+			\item Indirect addressing (2 modes: IDA, MIDA)
+			\item Suspend execution
+			\item ...
+		\end{itemize}
 		}
-	\end{minipage}\\
-	\end{tabular}
+
+		\fromSlide*{6}{\item Byte count}
+		\fromSlide*{7}{\item Buffer address}
+	\end{itemize}
+	}
 \end{slide}}
 
 % 3) lots of registers