text: Figure 1-1 SNIA shared storage model, version 21 
  
  The model consists of the following layers: 
  
  (cid:2) Application: The user of the storage domain. 
  
  (cid:2) Storage domain: 
  
  – File/record/namespace virtualization and File/record subsystem 
  – Block Virtualization 
  – Block subsystem 
  
  Applications typically read and write data as vectors of bytes or records. However, storage 
  presents data as vectors of blocks of a constant size (512 or in the newer devices, 4096 bytes 
  per block). 