The type of a pipe determines how data is written to a named pipe, and the read mode determines how data is read from a named pipe. Data can be transmitted through a named pipe as either a stream of bytes or as a stream of messages. When using the CreateNamedPipe function to create an instance of a named pipe, the server process specifies the pipe's type, the type it must specify for all instances.
A byte-type pipe is created if PIPE_TYPE_BYTE is specified or, by default, if no type is specified. This means that data is written to the pipe as a stream of bytes, and the system does not differentiate between the bytes written in different write operations. A handle to a byte-type pipe can be in byte-read mode only.
A message-type pipe is created if PIPE_TYPE_MESSAGE is specified. This means that the system treats each write operation to the pipe as a message unit. A handle to a message-type pipe can be in either byte-read or message-read mode.