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diff --git a/apps/Orbix-Examples/Logger/a1.tex b/apps/Orbix-Examples/Logger/a1.tex deleted file mode 100644 index 5d10042e26e..00000000000 --- a/apps/Orbix-Examples/Logger/a1.tex +++ /dev/null @@ -1,232 +0,0 @@ -\documentstyle[times,11pt,moretext] {article} -\input macros -\input widen -\input psfig - -\begin{document} -\centerline{\Large Washington University} -\centerline{\Large Department of Computer Science} -\bigskip -\centerline{\large CS523: Distributed Operating Systems} -%\smallskip -%\centerline{\large Spring 1995} -\bigskip -\centerline{\large Programming Project} -% \centerline{\large Due Tuesday, January $31^{st}$, 1995} - -\section{Overview} - -In this assignment, you will implement a distributed logging service -shown in Figure~\ref{logenv}. Applications use this service to log -information (such as error notifications, debugging traces, and status -updates) in a distributed environment. In this service, CORBA remote -operations are used to send logging records to a central logging -server. The logging server outputs the logging records to a console, -a printer, a file, or a network management database, etc. - -\section{Design and Implementation Issues} - -The distributed logging service will be designed as a client/server -pair, containing the objects shown in Figure~\ref{simplog}. - -\subsection{CORBA IDL Specification} -The following CORBA IDL specification defines the logging interface: - -{ -\small -\ls{0.9} -\begin{verbatim} -// IDL schema definition -interface Logger -{ - // Types of logging messages. - enum Log_Priority { - LM_DEBUG, // Debugging messages - LM_WARNING, // Warning messages - LM_ERROR, // Errors - LM_EMERG // A panic condition - }; - - // Format of the logging record. - struct Log_Record { - Log_Priority type; // Type of logging message. - long time; // Time stamp at sender. - long app_id; // Process ID of sender. - long host_addr; // IP address of the sender. - sequence<char> msg_data; // Sender-specific logging message. - }; - - // Transmit a Log_Record to the logging server. - oneway void log (in Log_Record log_rec); - - // Toggle verbose formatting - attribute char verbose; -}; -\end{verbatim}} - -\begin{figure} -\center{\ \psfig{figure=graphics/logsimp.eps,width=13cm}\ } -\vspace{-0.12in} -\caption{Distributed Logging Service} -\label{logenv} -\end{figure} - -You will use a CORBA IDL compiler to translate this specification into -client-side {\em stubs} and server-side {\em skeletons}. The client -application (which you must write) will use the stubs as a {\em proxy} -to access the logging services provided by the server. You must also -write the implementation of the server, which provides the logging -service. - -\subsection{Client and Server Functionality} -For the purposes of the assignment, you can make the client driver -program very simple. The client can read a line from its standard -input and send it to the logging server. The server can then format -and print the line on its standard output. For example, if you type -this line to the client: - -\begin{verbatim} -To boldly go where no one has gone before -\end{verbatim} - -\noindent Then the server should output something like this: - -\begin{verbatim} -Jan 24 14:50:28 1995@tango.cs.wustl.edu@18352@LM_DEBUG -::To boldly go where no one has gone before -\end{verbatim} - -\noindent Note that the server has printed out the logging message -timestamp, sender's hostname and process id, and the message priority, -followed by the logging message data. - -\begin{figure} -\center{\ \psfig{figure=graphics/simplog.eps,width=13cm}\ } -\vspace{-0.12in} -\caption{CORBA-based Logger Design} -\label{simplog} -\end{figure} - -Note that in order to pass the client's IP address (which is -represented as a 4-byte {\tt long}) in the logging message, you'll -need to learn about several other UNIX routines. On the client-side -you'll need to use {\tt uname(2)} and {\tt gethostbyname(2)} to -determine the IP address of the client host. On the server-side, -you'll need to use the {\tt gethostbyaddr(2)} function to convert the -4-byte IP host address into an ASCII version of the host name. I -recommend that you check the manual pages and read Richard Steven's -book ``UNIX Network Programming'' for more details on using these -functions. - -\subsection{Invoking the Client and Server} -Once the client and server components are written, compiled, and -linked together you will use the {\tt putit} command to register the -server with the Orbix daemon. You'll then need to start up a copy of -{\tt orbixd} (if there isn't already one running). {\tt orbixd} -serves as the Object Request Broker for the local endpoint. - -A client will bind to the {\tt Logger} interface via the generated -{\tt Logger::\_bind} method. There are two general ways to use this -method. The first is to explicitly pass in the name of the server -where {\tt orbixd} is running (your client should accept a -command-line argument that is the name of the server, {\em e.g.,} -``tango.cs.wustl.edu''). - -The second method is to use the CORBA locator service to get an object -reference for the logging service. You'll need to read the Orbix -documentation to learn how to set up a location file. This file will -enable you to omit the name of the server in the call to {\tt -Logger::\_bind}. By using the locator server, your clients can bind -to object's implicitly. Make sure that your solution will work for -either implicit or explicit service location. - -Once the client application has bound (either explicitly or -implicitly) to an object reference for the {\tt Logger}, it can log -messages by calling the {\tt log} method via the object reference -proxy. - -\subsection{Performance Measurement} - -An important part of developing distributed systems is understanding -the performance implications of different design approaches. In order -to measure the performance overhead of using CORBA to build the -Logger, you will write a simple extension to the original {\tt Logger} -interface, as follows: - -{ -\small -\ls{0.9} -\begin{verbatim} -// IDL schema definition -interface Profile_Logger - : Logger // Profile_Logger IS-A Logger -{ - // Stores the amount of time that has elapsed. - struct Elapsed_Time - { - double real_time; - double user_time; - double system_time; - }; - - // Activate the timer. - void start_timer (void); - - // Deactivate the timer and return the elapsed time. - void stop_timer (out Elapsed_Time et); -}; -\end{verbatim}} - -\noindent You will need to modify your client program so that it can -time a series of {\tt Logger::log} operations for various sizes of -logging messages. This will help us understand the performance -overhead of CORBA. - -The main benchmarking should take place within a loop in your client -program. Basically, your client call {\tt -Profile\_Logger::start\_timer} just before sending the first of the -logging messages. After a suitable number of iterations (defined on -the command-line), you client will call {\tt -Profile\_Logger::stop\_timer} to determine and report the elapsed time -to the user. You should print out the ``real'' time, as well as the -``system $+$ user'' times. Make sure that you print out the -throughput in terms of megabits/sec (rather than bytes/sec or -kbytes/sec). Be sure to include the fixed-sized {\tt Log\_Record} -object, as well as the variable-sized {\tt msg\_data} portion in your -computations. - -The number of iterations and the size of the messages sent by the -client should be parameterizable on the command-line. Make sure that -your timing tests are run between processes on two different machines -(rather than processes on the same machine). If possible, try to run -the client and server processes on two machines on the same subnet. - -When you are finished with your timing test, you should explain the -timing results and indicate trends that you observed. - -\section{Learning and Using CORBA} - -To help you learn how CORBA works, I will be making copies of the -Orbix programmer's manual available for a small reproduction fee. -This manual explains how to program in CORBA. I will announce in -class where this will be available. - -We will be using IONA's Orbix CORBA Object Request Broker (ORB) -implementation. The libraries, executables, CORBA IDL compiler, and -example demo applications are located in {\tt -/project/adaptive/Orbix}. Please note that this is an automounted -directory, so you will need to {\tt cd} directly to it in order to see -the contents. To configure Orbix for your environment, copy the {\tt -/project/adaptive/Orbix/Orbix.cfg} file to your account. You'll need -to set the environment variable {\tt IT\_CONFIG\_PATH} to the complete -path where this file is located. - -\section{Concluding Remarks} -In office hours and in class, we will discuss how to use C++ and CORBA -in order to develop your solutions. Note that this assignment will -teach you many skills required to become adept at network programming. -However, it also will require a great deal of thought and planning. -Please make sure you start early, come to office hours, and ask lots -of questions. - -\end{document} |