n, an independent ROM as the remote booting chip is set in the client, storing the codes of the ETHERBOOT protocol. Similar to the above-mentioned example, a Linux system is installed on one of the servers as its operating system. A DHCP server, a TFTP server and an NFS server are pre-installed on the server. After being powered on, the client first uses a DHCP service to get its IP address from the server, then downloads and loads the OS kernel mirror, shifting the control, and loading the root file system mirror (including initial applications) through NFS protocol.
In the third embodiment of the invention, an independent ROM as the remote booting chip is set in the client, storing the codes of the RPL (Remote Program Load) protocol. A Windows 2000 server is installed on one of the servers as its OS in advance with the remote booting service of the Windows NT4 because the Windows 2000 server cannot provide support for remote booting by itself. After the client is powered on, it uses the RPL protocol to download and load the DOS or the Windows 3.2 OS mirror, and initial applications. After shifting the control, it may use METAFRAME to connect to servers for resource henceforth.
In the fourth embodiment of the invention, the codes of PXE are stored in an independent ROM as the remote booting chip on the mainboard. A Windows 2000 Server system is installed on one of the servers as its operating system. Both DHCP and PXE-PDK services are preset on the server. A sample client mirror is produced as follows: 1) temporarily connect a harddisk to the IDE interface of the client, 2) install on it the Windows 98 OS and initial application programs as done with a normal PC, 3) set and make the mirror file according to the LITENET. After that, the mirror is stored on the server. After being powered on, the client downloads and loads the mirror by the PXE. By using NET USE, the shared file of Windows 2000 server can be mapped into a network virtual disk for each client, therefore providing the data storage service for the Windows 98 system
In the fifth embodiment of the invention, an independent ROM as the remote booting chip is set on the client mainboard, storing a remote booting protocol to support the loading of multi-OS. A Linux system is installed on one of the servers as its operating system. A DHCP server, NFS service, and SAMBA service are preset and installed on the server. The server also stores various Linux and Windows OS mirrors, including corresponding initial applications. The remote booting chip is slightly different in functionality from the above mentioned ones. The client downloads a script from the server after getting its own IP address. By executing the script, the client prompts users to select the desired OS from a candidate list displayed on the client's screen. According to the user's selection, the client downloads and loads the corresponding mirror. The client is provided with file services by NFS or SAMBA services, and uses demand loading techniques to implement application optimization of the client, thus it can support abundant desktop applications.
As an improvement, by using some existing virtual disk techniques (such as RamDisk, NFS, NBD etc.), client daemon programs can be preset within the downloading mirrors stored on the server, while the corresponding server daemon programs are preset on the server or some other servers, so that virtual disk space for this client are made both on the server and/or local memory. So after the client daemon program has been run by a client, it can be provided with persistent and/or temporary private disk space (different from the diskless workstation). As a result, data generated during or after the computing process on the client can be persistently stored into servers' storage and/or cached in its memory. For the sake of safety, data temporarily stored in the virtual disk in the client memory can be exported manually by the system administrator from time to time, or automatically exported to servers' storage through NFS service by setting another client daemon 