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Chapter 9: Glossary
Network Storage System (NSS) Administrator Guide
Chapter
9
F
FAT32:
File Allocation Table. Microsoft developed this partially patented filesystem for MS-DOS. It is
the primary filesystem for consumer versions of Microsoft Windows up to and including Windows
Me. Because it is considered relatively simple, the FAT filesystem is supported by virtually all existing
operating systems for personal computers. This ubiquity makes it an ideal format for floppy disks
and solid-state memory cards, and a convenient way of sharing data between disparate operating
systems installed on the same computer (a dual boot environment). The most common
implementations have a serious drawback in that when files are deleted and new files written to the
media, their fragments tend to become scattered over the entire media, making reading and writing
a slow process. Defragmentation is one solution to this, but is often a lengthy process in itself and
has to be repeated regularly to keep the FAT filesystem clean. To overcome the volume size limit of
FAT16, while still allowing DOS real-mode code to handle the format without unnecessarily reducing
the available conventional memory, Microsoft decided to implement a newer generation of FAT,
known as FAT32, with cluster counts held in a 32-bit field, of which 28 bits are currently used.
File Sharing Protocol:
A high-level network protocol that provides the structure and language for file
requests between clients and servers, including the commands for opening, reading, writing and
closing files across the network. It may also provide access to the directory services. It is sometimes
referred to as a "client/server protocol" and functions at the application layer (layer 7 of the OSI
model). In order for a client to have access to multiple servers running different operating systems,
either the client supports the file sharing protocol of each operating system or the server supports the
file sharing protocol of each client. Software that adds this capability is very common and allows
interoperability between Windows, Macintosh, NetWare and Unix platforms. Examples of file
sharing protocols include: CIFS/SMB (Windows), and NFS (UNIX).
FTP:
File Transfer Protocol. FTP is a standard Internet protocol that uses the Internet’s TCP/IP protocols
to exchange files between computers on the Internet. FTP can be used to transfer, download, and
upload files individually or in batch form.
FTPS:
File Transfer Protocol over SSL. FTPS is similar to the standard FTP but because it operates over
an encrypted link (SSL), it is a more secure way to transfer files over the Internet. The NSS supports
Explicit FTPS (versus Implicit FTPS). Explicit FTPS is named for the command issued to indicate that
TLS security should be used. This is the preferred method according to the RFC defining FTP over TLS.
The client connects to the server port 21 and starts an unencrypted FTP session as normal, but
requests that TLS security be used and performs the appropriate handshake before sending any
sensitive data.
G
Gigabit:
Also Gbit or Gb. A unit of information or data storage equivalent to 1,000,000,000 (1
billion) bits.
Gigabtye (GB):
A unit of information or data storage equivalent to 1,000,000,000 (1 billion) bytes.
H
High Availability:
A term applied to a class of electronic devices where a system design protocol
has been applied and implemented to ensure a higher/improved degree of operational continuity
during a given measurement period.
