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Unix and Unix-like operating allow for any character in file names other than the slash, and names are case sensitive. Microsoft Windows file names are not case sensitive.

File systems may provide journaling, which provides safe recovery in the event of a system crash. A journaled file system writes information twice: first to the journal, which is a log of file system operations, then to its proper place in the ordinary file system. In the event of a crash, the system can recover to a consistent state by replaying a portion of the journal. In contrast, non-journaled file systems typically need to be examined in their entirety by a utility such as fsck or chkdsk. Soft update is an alternative to journalling that avoids the redundant writes by carefully ordering the update operations. Log-structured file systems and ZFS also differ from traditional journaled file systems in that they avoid inconsistencies by always writing new copies of the data, eschewing in-place updates.

Many Linux distributions support some or all of ext2, ext3, ReiserFS, Reiser4, GFS, GFS2, OCFS, OCFS2, and NILFS. Linux also has full support for XFS and JFS, along with the FAT file systems, and NTFS.

Microsoft Windows includes support for FAT12, FAT16, FAT32, and NTFS. The NTFS file system is the most efficient and reliable of the four Windows file systems, and as of Windows Vista, is the only file system which the operating system can be installed on. Windows Embedded CE 6.0 introduced ExFAT, a file system suitable for flash drives.

Mac OS X supports HFS+ as its primary file system, and it supports several other file systems as well, including FAT16, FAT32, NTFS and ZFS.

Common to all these (and other) operating systems is support for file systems typically found on removable media. FAT12 is the file system most commonly found on floppy discs. ISO 9660 and Universal Disk Format are two common formats that target Compact Discs and DVDs, respectively. Mount Rainier is a newer extension to UDF supported by Linux 2.6 kernels and Windows-Vista that facilitates rewriting to DVDs in the same fashion as what has been possible with floppy disks.

Networking

Most current operating systems are capable of using the TCP/IP networking protocols. This means that one system can appear on a network of the other and share resources such as files, printers, and scanners using either wired or wireless connections.

Many operating systems also support one or more vendor-specific legacy networking protocols as well, for example, SNA on IBM systems, DECnet on systems from Digital Equipment Corporation, and Microsoft-specific protocols on Windows. Specific protocols for specific tasks may also be supported such as NFS for file access.

Security

Many operating systems include some level of security. Security is based on the two ideas that:

  • The operating system provides access to a number of resources, directly or indirectly, such as files on a local disk, privileged system calls, personal information about users, and the services offered by the programs running on the system;
  • The operating system is capable of distinguishing between some requesters of these resources who are authorized (allowed) to access the resource, and others who are not authorized (forbidden). While some systems may simply distinguish between "privileged" and "non-privileged", systems commonly have a form of requester identity, such as a user name. Requesters, in turn, divide into two categories:
  • Internal security: an already running program. On some systems, a program once it is running has no limitations, but commonly the program has an identity which it keeps and is used to check all of its requests for resources.
  • External security: a new request from outside the computer, such as a login at a connected console or some kind of network connection. To establish identity there may be a process of authentication. Often a username must be quoted, and each username may have a password. Other methods of authentication, such as magnetic cards or biometric data, might be used instead. In some cases, especially connections from the network, resources may be accessed with no authentication at all.

Questions & Answers

different between demand and supply
Francis Reply
what is the demand and supply of Qd=40,000-6P Qs=14P-28,000 the equilibrium price
Rocky Reply
3400
Ram
what is economics by Adams smith
Diana Reply
economics by Adams Smith's
Francis
to earn wealth more and more
Ram
what are the poor performance of the monopolies
Thandolwethu Reply
it controls only price or production not both a same time
Ram
Difference between demand and supply
Kareem Reply
demand talks about the consumers and supply also talks about producers
Bright
demand talks about the relationship between price and the quantity demanded for a certain goods and supply talks about the relationship between price and quantity supply of a certain goods .
Mutala
demand show the quality demanded at different price n time whereas supply show the quality ready to sell in market by seller at different price n time.
Ram
describe the issue gain from trade will improve economic growth and living standard.
Allison Reply
discribe gain from trade will improve economic growth and living standard
Allison
discribe gain from trade will improve economic growth and living standard
Allison
what is the outcome of exchange rate?
Allison
gain from international trade to a country which import are elastic n export are inelastic
Ram
what is utility
Roberta Reply
the capacity of a good to satisfy our want.
Ram
what is the relationship between the elasticity of demand and total revenue
Atedago Reply
I don't know
Taofeek
negative. but for unit elasticity of demand, the relationship doesn't exist between them.
Ali
what is income elasticity of demand
Esther Reply
income elasticity of demand measure the degree of responsiveness of demand for a commodity to a small change in the income of the consumer
Atedago
monopolistic competition has all except which of the following basic characteristics?
Sharon Reply
what are the Features of money
Abubakarr Reply
how to calculate the elasticity of supply?
Asnaira Reply
PES=Qs2-Qs1/Qs1÷P2-P1/P1
Soko
why is economics important
Gifted Reply
why is it important
Gifted Reply
for what?
Vicky
economics
Gifted
what is demand
Mutala Reply
Demand Is Anything that A Customer are willing and able to buy at different price level.
Basit
what demand schedule
Mutala
demand schedule is a tabular representation of different quantities of commodities that consumers are willing to purchase at a specific price and time while other factors are constant.
MEOW
A full account of the demand, or perhaps we can say, the state of demand for any goods in a given market at a given time should state what the volume (weekly) of sales would be at each of a series of prices. Such an account, taking the form of a tabular statement, is known as a demand schedule.
MEOW
State the type of elasticity of demand
Emmanuel
price elasticity of demand . and it refers to the degree of responsiveness of change in quantity demanded for a commodity to a change in price if the commodity itself
Mutala
Researchers demonstrated that the hippocampus functions in memory processing by creating lesions in the hippocampi of rats, which resulted in ________.
Mapo Reply
The formulation of new memories is sometimes called ________, and the process of bringing up old memories is called ________.
Mapo Reply
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Source:  OpenStax, Operating systems. OpenStax CNX. Aug 13, 2009 Download for free at http://cnx.org/content/col10785/1.2
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