Network boot system

A network boot system, comprising:

• a client terminal that has a physical storage device,
• a network boot server that provides a disk image as a virtual disk, the disk image including an operating system (OS) operating on the client terminal,
• the network boot server and the client terminal being connected through a network,
• the client terminal having a physical memory that temporarily stores data that is necessary at a boot time of the OS and a network interface for accessing the server through the network, and
• the OS having a read cache driver for driving the storage device, and
• a read cache mechanism that, when the read cache driver receives a read request signal from the client terminal, stores data that was read from the server at reading time as cache data in a read cache region of the storage device, wherein
• the read cache mechanism has
• a mapping table that indicates an address of the read cache region corresponding to an address of the data at the reading time from the server,
• a cache storing means that in order and sequentially stores the data at the reading time from the server from a top side of the read cache region,
• a table storing means that stores the address of the data that was at the reading time from the server and the address of the read cache region, these addresses corresponding to each other, and
• when using the cache data, the read cache mechanism accesses the address of the read cache region based on the address of the data that was at the reading time from the server and the mapping table.