The IBM NetVista IDF Builder and SDF Creator utility is used to create a flash image. Once created, the flash card of a Linux thin client can be updated from the client during the client-side boot process.An Image Description File, or IDF, is what is used to update the flash card. It is made up of references to SDF package files. Each line in an IDF contains the name of the SDF package, the SDF size, CRC value, SDF creation date, and where the SDF can be found on the server. An IDF is constructed using the IDF Builder. A Software Description File, or SDF, represents a software package. Its contents are similar to an IDF except that each line in a SDF contains a reference to a software file such as a library, binary, text file, etc. A SDF package is constructed using the SDF Creator.