CS 3733 Operating Systems

• Make a separate directory for this assignment.

• Download the UICI library:
  • server.c
  • client.c
  • uici.c
  • uici.h
  • makefile

• Compile and run this code to make sure that the client can send to the server.

• Modify server.c so that instead of copying from the network to standard output, it does the following in a loop:
  • Open the audio device.
  • Call play_open_file using the communication file descriptor as the parameter.
  • Close the audio device.
  • Resume listening.

• Modify client.c so that instead of copying from standard input to the network, it does the following:
  • Open the audio device.
  • Call record_to_open_file using the communication file descriptor as the parameter.
  Note: At this point you will just control-C out of the client to stop.

• Add a threshold parameter to record_to_open_file. If threshold is negative, it is ignored. If the threshold is positive, it is used to threshold the incoming audio. That is. After a block has been read with read_audio, if any of the bytes in the read block are above the threshold, then the block is written. If all of the bytes are below the threshold, the block is thrown away. The threshold is used so that you won't be sending silence over the network. Modify your client and server so that they each take the threshold value as a command line argument.

Part II: A Two-way Network Intercom - Due April 3, 1998

Modify the client and server so that each forks a child after opening the audio device. The child calls the record_to_open_file while the parent calls play_from_open_file.