An offline reader (sometimes called an offline browser or offline navigator) is

computer software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consist ...

that downloads e-mail,

newsgroup A Usenet newsgroup is a repository usually within the Usenet system, for messages posted from users in different locations using the Internet. They are discussion groups and are not devoted to publishing news. Newsgroups are technically disti ...

posts or web pages, making them available when the computer is

offline In computer technology and telecommunications, online indicates a state of connectivity and offline indicates a disconnected state. In modern terminology, this usually refers to an Internet connection, but (especially when expressed "on line" o ...

: not connected to a server. Offline readers are useful for portable computers and

dial-up access Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a connection to an Internet service provider (ISP) by dialing a telephone number on a conventional telepho ...

Variations

Website-mirroring software

Website mirroring software is software that allows for the download of a copy of an entire

website A website (also written as a web site) is a collection of web pages and related content that is identified by a common domain name and published on at least one web server. Examples of notable websites are Google, Facebook, Amazon, and W ...

to the local hard disk for offline browsing. In effect, the downloaded copy serves as a

mirror A mirror or looking glass is an object that reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the direction of the im ...

of the original site.

Web crawler A Web crawler, sometimes called a spider or spiderbot and often shortened to crawler, is an Internet bot that systematically browses the World Wide Web and that is typically operated by search engines for the purpose of Web indexing (''web s ...

software such as Wget can be used to generate a site mirror.

Offline mail and news readers

Offline mail readers are

computer program A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. Computer programs are one component of software, which also includes software documentation, documentation and oth ...

s that allow users to read electronic mail or other messages (for example, those on bulletin board systems) with a minimum of connection time to the server storing the messages. BBS

server Server may refer to: Computing *Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients Role * Waiting staff, those who work at a restaurant or a bar attending customers and su ...

s accomplished this by packaging up multiple messages into a compressed file, e.g., a QWK packet, for the user to download using, e.g., Xmodem, Ymodem,

Zmodem ZMODEM is an inline file transfer protocol developed by Chuck Forsberg in 1986, in a project funded by Telenet in order to improve file transfers on their X.25 network. In addition to dramatically improved performance compared to older protocol ...

, and then disconnect. The user reads and replies to the messages locally and packages up and uploads any replies or new messages back to the server upon the next connection. Internet mail servers using POP3 or

IMAP4 In computing, the Internet Message Access Protocol (IMAP) is an Internet standard protocol used by email clients to retrieve email messages from a mail server over a TCP/IP connection. IMAP is defined by . IMAP was designed with the goal of ...

send the messages uncompressed as part of the protocol, and outbound messages using SMTP are also uncompressed. Offline news readers using NNTP are similar, but the messages are organized into news groups. Most e-mail protocols, like the common

POP Pop or POP may refer to: Arts, entertainment, and media Music * Pop music, a musical genre Artists * POP, a Japanese idol group now known as Gang Parade * Pop!, a UK pop group * Pop! featuring Angie Hart, an Australian band Albums * ''Pop'' ( ...

3 and IMAP4 used for

internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, p ...

mail, need be on-line only during message transfer; the same applies to the NNTP protocol used by

Usenet Usenet () is a worldwide distributed discussion system available on computers. It was developed from the general-purpose Unix-to-Unix Copy (UUCP) dial-up network architecture. Tom Truscott and Jim Ellis conceived the idea in 1979, and it wa ...

(Network news). Most end-user mailers, such as Outlook Express and

AOL AOL (stylized as Aol., formerly a company known as AOL Inc. and originally known as America Online) is an American web portal and online service provider based in New York City. It is a brand marketed by the current incarnation of Yahoo! Inc. ...

, can be used offline even if they are mainly intended to be used online, but some mailers such as Juno are mainly intended to be used offline. Off-line mail readers are generally considered to be those systems that did not originally offer such functionality, notably on

bulletin board system A bulletin board system (BBS), also called computer bulletin board service (CBBS), is a computer server running software that allows users to connect to the system using a terminal program. Once logged in, the user can perform functions such ...

s where toll charges and tying up telephone lines were a major concern. Users of large networks such as FidoNet regularly used offline mail readers, and it was also used for

UseNet Usenet () is a worldwide distributed discussion system available on computers. It was developed from the general-purpose Unix-to-Unix Copy (UUCP) dial-up network architecture. Tom Truscott and Jim Ellis conceived the idea in 1979, and it wa ...

messages on the internet, which is also an online system. The two most common formats for FidoNet BBS's were Blue Wave and QWK. Less well-known examples include Silver Xpress's OPX, XRS, OMEM,

SOUP Soup is a primarily liquid food, generally served warm or hot (but may be cool or cold), that is made by combining ingredients of meat or vegetables with stock, milk, or water. Hot soups are additionally characterized by boiling soli ...

Variations

Website-mirroring software

Offline mail and news readers

List

See also

Notes

References