A multi-file CDF ( MULTI_FILE) consists of one file (with extension .cdf ) containing control information and attribute entry data and a separate file for each variable defined in the CDF (with extensions .v0,.v1,... for rVariables and .z0,.z1,... for zVariables). Each variable file contains the data values for the corresponding variable. (The control information for each variable is stored in the .cdf file.)