## 4 Experimental Process and Results  
The section demonstrates the feasibility of Clonezilla live with the BT protocol for massive deployment by deploying Ubuntu Linux to massive machines in a computer classroom. The experiments deployed a Linux system to one to 32 clients using both the multicast solution previously developed by the authors [3] and the newly developed BT-based solution. The experimental environment consisted of the following machines and image:  
* Network switch: the Cisco Catalyst 3560G switch with 48 gigabits ports was used as the network switch. The multicast function was enabled, and the spanning tree protocol was disabled to avoid the timeout of network booting in the client machines. * Server: a Dell T1700 machine plays the role of a server. The central processing unit (CPU) is the 3.3 GHz Intel Xeon E3-1226 processor. The size of the Dynamic Random Access Memory (DRAM) is 16 gigabytes (GB). The size of the hard disk is one terabyte (TB). Figure 8: The BT solution for massive system deployment. Figure 7: The schematic diagram about a massively deploying image to a bare-metal machine using the BT solution. DHCP: Dynamic Host Configuration Protocol. * PC clients: Dell T1700 PCs with the same configuration as the one serving as the server were used as clients. * The image of the Linux and applications: an Ubuntu Linux system with applications and data installed on a template PC occupying 50 GB of the hard disk. The files were saved by Clonezilla live, and the image was compressed using the parallel Zstandard (pzstd), which is a fast lossless compression algorithm [58]. The image size is deliberately designed to be larger than the RAM size of the PC client in the experiment to ensure the feasibility of the proposed system to solve the temporary storage shortage issue. In the experiments, 32 PC clients were connected to the server using a Cisco Catalyst 3560G switch and the Category 5e network cables. The configuration of the experiments of massive deployment in large-scale computers is shown in Figure 9.  
The image was put in the local hard drive of the server, and the server entered the lite-server mode of Clonezilla live, which can relay the DHCP requests from the PC clients to the existing DHCP service in the LAN. After choosing the image, the BT and multicast solutions were chosen for the massive deployment. The clients were booted from the PXE. Thirty-two experiments to deploy the image to one to 32 clients were conducted. When some of the clients were deployed, the remaining clients of the 32 machines that were not deployed were powered off. Table 2 summarizes the total time required to deploy the machines using the unicast, BT, and multicast solutions. The ratio of the total time required for massive deployment using the BT solution to the time required for the massive deployment by the multicast solution is also summarized in Table 2. For a perfect situation, we assume here that there is no overhead during the unicast deployment in sequence, so the time to deploy multiple machines is obtained by multiplying the time required for one machine by the number of client machine(s). Here, \"total time\" means the time required to deploy the file system(s). Other time required for system booting, partition table creation, image file conversion, and informing the server regarding deployment results is not included. Figure 10 demonstrates the results of the massive deployments. Figure 10a,b demonstrate the total time and average time required by both the BT and multicast solutions to deploy the image, respectively. Based on the illustrations, when the number of clients to be deployed is smaller than 11, the total time required for system deployment was greater under the BT solution than the multicast solution. However, when the number of clients is equal to or larger than 11, the total deployment time required for the BT solution is less than the time required by the multicast solution.