What is embedded linux ?

Hi All !
I have a silly question. How does embedded linux works without disk
support ?
I mean from where it loads shell and other application task images
without any file system
support ? For VxWOrks/pSOS have a single object file. How about Embedded
Linux ?
I am confused on this matter. Or it always need some kind of file
support like NFS to boot ?

Pravin


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