A data transmission system for transmitting a data file from a server to a client device includes a processor, a memory and a network interface device. The memory includes a user space and a kernel space. The data file is stored in the kernel space. The processor receives a transmission request from the client device for transmitting the data file. The processor maps a set of virtual addresses corresponding to the data file to the user space as a mapped data file, and stores a set of physical addresses corresponding to the set of virtual addresses in a set of meta-buffers of a socket created in the user space. The network interface device retrieves the data file from the kernel space based on the set of physical addresses from the set of meta-buffers, and transmits the data file to the client device.