Chapter
4
Miscellaneous
This chapter provides information on various concepts used in μC/FS. We decided to
include this chapter early in the μC/FS manual so that you can start using μC/FS as soon as
possible. In fact, we assume you know little about μC/FS and file systems. Concepts will be
introduced as needed.
4-1 NOMENCLATURE
This manual uses a set of terms to consistently describe operation of μC/FS and its hardware
and software environment. The following is a small list of these terms, with definitions.
A file system suite is software which can find and access files and directories. Using “file
system suite” rather than “file system” eliminates any need for disambiguation among the
second term’s several meanings, which include “a system for organizing directories and
files”, “a collection of files and directories stored on a drive” and (commonly) the software
which will be referred to as a file system suite. The term file system will always mean a
collection of files and directories stored on a drive (or, in this document, volume).
A device driver (or just driver) is a code module which allows the general-purpose file
system suite to access a specific type of device. A device driver is registered with the file
system suite.
A device is an instance of a device type that is accessed using a device driver. An
addressable area (typically of 512 bytes) on a device is a sector. A sector is the smallest area
that (from the file system suite’s point of view) can be atomically read or written.
Several devices can use the same device driver. These are distinguished by each having a
unique unit number . Consequently, <DEVICE NAME>:<UNIT NUMBER>: is a unique device
identifier if all devices are required to have unique names. That requirement is enforced in
this file system suite.
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