SPOOLING

  要求设计一个SP00LING输出进程和两个请求输出的用户进程，以及一个SP00LING输出服务程序。当请求输出的用户进程希望输出一系列信息时，调用输出服务程序，由输出服务程序将该信息送入输出井。待遇到一个输出结束标志时，表示进程该次的输出文件输出结束。之后，申请一个输出请求块(用来记录请求输出的用户进程的名字、信息在输出井中的位置、要输出信息的长度等)，等待SP00LING进程进行输出。 SP00LING输出进程工作时，根据请求块记录的各进程要输出的信息，将其实际输出到打印机或显示器。这里，SP00LING输出进程与请求输出的用户进程可并发运行。 (Asked to design a user process SP00LING request output and two output processes, and outputs a SP00LING service program. When users want to process requests output output range information, call the output service program, service program by the output information into the output shaft. Treatment to an output end of the flag, which means that the process of the second output file output end. Thereafter, the application of an output request block (name of the user to record the output of the process request, the information on the position of the output well, and length information to be outputted), the process waits SP00LING output. When SP00LING output process work, information requested under each process block records to be output, its actual output to a printer or monitor. Here, the user process and the output process SP00LING request output can be run concurrently.)