**2. Architecture of PCMGM**

PCMGM includes two parts: one is DNE that is the physical computing devices for the parallel cache, and DNE is composed of computer clusters connected through LAN and Intranet, and all the cache computers are not special, the other is the agent system, and we call it GMG (Global Management Group). GMG is composed of a management agent system (MAS), the application agent (AA), and a lots of cache agents (CA). The architecture is presented in figure1, and the definitions of NA, CA, CN, GA, SA are described as the definition 1 ~7 and the section 3.

Fig. 1. The architecture of PCMGM

#### **2.1 DNE**

**Definition.1.** Cache node (CN) is a computer and it is defined as CN (id, AS, RSV, st), where id is the identifier of CN; AS is the set of agents running on CN; RSV(rcpu, rmem, rdisk, rnet) denotes its resource support vector, rcpu is the power of its CPU, rmem is the power of its memory storage, rdisk is the power of its hard-disk , and rnet is the power of its network adapter; st{"Local", "Idle", "Caching"} is its states, "Local" denotes that this computer is working for local tasks, "Idle" denotes that this computer is not working , and "Caching" denotes that this computer is working for Grid in the form of cache.

**Definition.2.** Computer cluster (CC) is defined as CC (Master, CS), where Master is the main computer of CC; CS= {CN1, CN2 … CNp} is the set of all cache nodes in computer cluster.

**Definition.3.** Logical computer cluster (LCC) is defined as LCC (id, LCS, B, CC), where id denotes the identifier of LCC; LCS is the set of cache nodes of LCC; CC is the computer cluster which comprises LCC. Network bandwidth of LCC denotes as B.

So, the dynamic network environment (DNE) can be defined as DNE (Master, CCS, SVS, N, R), where Master is the main computer of DNE; CSS is the set of all computer clusters in DNE; SVS is the set of file servers to storage the files; N is its network set; R is the connection rules. All the free memories of the idle cache nodes in DNE are called the grid memory.

**Definition. 4.** Basic memory unit (BMU) is the uniform size of basic memory block as the allotting unit in PCMGM, and its unit is MB.

**Definition. 5.** Grid memory capacity (Gmc) is the total numbers of BMU provided by all cache nodes in DNE. The Gmc value is dynamic changed.
