Software Tools to Improve Note-Taking in the Classroom
Daniel PILON, Jacques RAYMOND, and Patricia RAYMOND

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The Log-In Tool

We assume that a closed LAN exists where the classroom server computer is always running and ready to log a professor and students. Only one course lecture with one professor and one or more students can be run on a single closed LAN. When a computer executes the main program, it automatically sends a broadcast packet to attempt to log in on the server; the server computer recognizes the packet and processes it. If students were already logged in and a request from a professor to log in were initiated, the students' computers would intercept the source address to update their internal professor address required by other tools. Similarly, any log-in packet sent by a late-comer will be intercepted by the professor's computer to have the student's name displayed on the professor's computer screen. The Ethernet frame format used by computers to log in is illustrated in figure 5, without the preamble and the FCS.

Destination Address Source Address Frame Type Function Code Total Nb of PCs LæProf Mode Nickname
FFFFFF Originator's
NIC Address
FACEh Integer
LogI=590
Integer Byte String[37]
Fig 5. Log-in frame format

When a computer logs in, the log-in code is put in the Function Code field, the LæProf Mode field is filled with whether the computer is in Professor mode (equal to 1) or is in Student mode (equal to 2), and the Nickname field is filled with the name of the individual found in the configuration file. The Total Nb of PCs field is not used at this stage.

When the server computer receives this type of frame, it verifies if the requested computer is not already logged in by looking in an internal linked list; if not, the server adds the requested computer address in the list and sends back to the originator the packet as an acknowledgment. However, before sending the frame, the software updates the LæProf Mode field with a value equal to zero, fills the Total Number of PCs field with the number of computers presently logged in and finally, fills the Nickname field with a null string. If a log in request is done by a student when the professor is already logged in (a late-comer), the Nickname field will contain the physical address of the professor computer. The Ethernet frame format sent by the server's computer to any other computer requesting to log in is illustrated in figure 6, without the preamble and the FCS.

Destination Address Source Address Frame Type Function Code Total Nb of PCs LæProf Mode Nickname
Originator's
Address
Server's
Address
FACEh Integer
LogI=590
Integer 0 '' or Professor's Address
Fig 6. Log-in acknowledgement frame format

When the originator receives the acknowledgment, a message indicating his/her nickname and the number of individuals presently on the network is displayed on his/her computer's screen.

The data flow occurring during a log-in session is illustrated in figure 7.

Log-in session
Fig 7. Log-in session data flow

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