Windows NT Systems Programming: Spring 2000

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Assignment 3: Student Record Multi-Client Server

Description: You will modify the student records program (ex16b) so that the student record list is kept on a server. The client will have the same user interface as Ex16b, but will store and retrieve student records from the server. This server can be accessed by multiple clients simultaneously. Therefore you need to be concerned about potential synchronization conflicts.

You can work on this project in a team of 2 if you choose. The requirements for a team project are different in that the server is required to have a user interface (see details below).

Due: March 24 (Friday).

FUNCTIONAL REQUIREMENTS:

1. Client program should have the same interface as Ex16b. (which means that file save/open is NOT enabled even though it is there in the menu).
2. Server keeps the student record list NOT the document object in the client. The document object needs to keep at most one student record.
   The document object will therefore be more like that in EX16a, although it needs to be able to communicate with the server to save/retrieve student records.
3. Server must handle multiple clients simultaneously.
4. Synchronization is to be handled as follows.
   • Inserting a new student record is always done at the end of the list.
     Multiple clients can insert new records at the same time (subject to reasonable synchronization constraints).
   • No client can delete a student record which is being viewed by another client.
     A request to delete a record being viewed by another client will be denied.
   • There is no editing of an existing student record.
     Therefore, other than inserting a new record, there are no writers.
   • The list may change while a client is searching through it with new items added and existing ones deleted (as long as it is not the one the client is viewing). Therefore the indications that you are at the beginning or end of the list are not necessarily accurate.
     Because the list may be changed by other clients while it is being viewed and because these changes will not be broadcast to all clients, you chould not disable the home/end/prev/next menu items/toolbar.
   • The "home" and "end" menu/toolbar actions will take the client to the current home/end at the time the clients request reaches the server.
     However, after going to the end, new records can be added which change the end. The client does not have to be notified of this change. Thus it is possible that retrieving the next record after going to the end will retrieve a new record.
     In addition, records after the current record being viewed may be deleted making the current record the end of the list. Again the client is not notified that the current record is at the end. However if the client tries to retrieve the next record, a message box saying that this is the last record will be displayed and the current record will stay the same.

   The following rules are intended to avoid the multiple readers/writers problem and thus simplify synchronization.

5. The server must guarantee the integrity of the student record list using whatever synchronization you deem appropriate.
6. Your server should display informational messages whenever a new client is connected/disconnected. It should display all client actions (insert record, delete, retrieve) with the name of the student involved.

IMPLEMENTATION (NON-FUNCTIONAL) REQUIREMENTS:

1. Your server must start a new thread for each client.
2. You should submit a testing report which describes the tests you used to convince yourself that the system was working and their results.

HINTS:

• You can build your project using parts of ex16b and the NOMSv3 multiple client server example.
• You do not have to emulate the remote procedure call mechanim of NOMSv3. You can structure the communication whatever way you see is appropriate.
• More hints are available here.

Additional Requirements for a Team Assignment

• Clients must "login" before accessing the server.
• The server must support a GUI with a list of the currently logged in clients and their status as follows:
  • list of all actions (insert, delete, retrieve) including student name for each action.
  • Clicking on a client in the client list will bring up this list of actions.
• Server should keep a log of all clients who have previously logged in that session.
• Clients can log off or quit which should also log the client off.

Copyright chris wild 1999/2000.
For problems or questions regarding this web contact [Dr. Wild].
Last updated: March 14, 2000.