Executable application files can be stored on disks, in RAM, flash, or ROM.
They
can be stored on the target or anywhere else that is accessible over a network
connection.
The executables are loaded from a file system; and any file system for
which the kernel has support (ROMFS, NFS, ftp, and so on) can be used.
The
ROMFS file system technology is particularly useful for deployed systems. It
allows developers to bundle application executables with the VxWorks image into
a single file that the boot loader can load from ROM. Unlike other operating
systems, no root file system—such as on NFS or a diskette—is required to hold
application binaries, configuration files, and so on.
VxWorks provides a raw file system (rawFs) for use in systems that require only the
most basic disk I/O functions.
The special-purpose proc, sysfs, devpts, selinuxfs, binfmt_misc, and tmpfs file systems are part of the evaluated configuration. These are virtual file systems with no underlying physical storage, and represent data structures in kernel memory.
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Each VxWorks process has its
own region of virtual memory; processes do not overlap in virtual memory. This
flat virtual-memory map provides the following advantages:
■ Speed—Context switching is fast.
■ Ease of debugging
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