The Online Reader format was created by eBooks.com. It allows you to read the ebook online in the same web browser you used to purchase your ebook. Currently the Online Reader is based on the original PDF file of the ebook, so it displays in a very similar way to a PDF. Format definition is - the shape, size, and general makeup (as of something printed). How to use format in a sentence. Parquet Back to glossary. Parquet is an open source file format available to any project in the Hadoop ecosystem. Apache Parquet is designed for efficient as well as performant flat columnar storage format of data compared to row based files like CSV or TSV files.
The file format is the structure of a file that tells a program how to display its contents. For example, a Microsoft Word document saved in the .DOC file format is best viewed in Microsoft Word. Even if another program can open the file, it may not have all the features needed to display the document correctly.
Programs compatible with a file format can give an overview of a file but may not be able to display all the files features. Also, with some programs opening a file format that is not supported may give you garbage. Alien voice changer.
Common file formats
Below is a listing of common file formats you are most likely to encounter while working on a computer. Click on any of the links below for more information about the type of file or the extension.
| File type | File extension |
|---|---|
| Text | .asc .doc.docx.rtf.msg, .pdf.txt .wpd .wps |
| Image | .bmp .eps .gif.jpg .pict .png .psd .tif |
| Sound | .aac .au .mid.mp3 .ra .snd .wma.wav |
| Video | |
| Program | |
| Compressed | .arc .arj .gz .hqx .rar .sit .tar .z .zip |
Related pages
File, File extension, Software terms
Mbox is a generic term for a family of related file formats used for holding collections of email messages, first implemented for Fifth Edition Unix.
All messages in an mbox mailbox are concatenated and stored as plain text in a single file.Each message starts with the four characters 'From' followed by a space (the so named 'From_ line') and the sender's email address.RFC 4155 defines that a UTC timestamp follows after another separating space character.
Unlike the Internet protocols used for the exchange of email, the format used for the storage of email has never been formally defined through the RFC standardization mechanism and has been entirely left to the developer of an email client.However, the POSIX standard defined a loose frame in conjunction with the mailx program.In 2005 finally, the application/mbox media type was standardized as RFC 4155, and hints that mbox stores mailbox messages in their original Internet Message (RFC 2822) format, except for the used newline character, seven-bit clean data storage, and the requirement that each newly added message is terminated with a completely empty line within the mbox database.
A format similar to mbox is the MH Message Handling System. Other systems, such as Microsoft Exchange Server and the Cyrus IMAP server store mailboxes in centralised databases managed by the mail system and not directly accessible by individual users.The maildir mailbox format is often cited as an alternative to the mbox format for network email storage systems.
Family[edit]
The mbox format uses a single blank line followed by the string 'From ' (with a space) to delimit messages; this can create ambiguities if a message contains the same sequence in the message text.
Over the decades that followed, four popular but incompatible variants arose: mboxo, mboxrd, mboxcl, and mboxcl2. The naming scheme was developed by Daniel J. Bernstein, Rahul Dhesi, and others in 1996. Each originated from a different version of Unix. mboxcl and mboxcl2 originated from the file format used by Unix System V Release 4 mail tools. mboxrd was invented by Rahul Dhesi et al. as a rationalisation of mboxo and subsequently adopted by some Unix mail tools including qmail.
All these variants have the problem that the content of the message is modified in order to remove the ambiguities, as shown below, so that applications have to know which quoting rule has been used in order to perform the correct reversion, which turned out to be impractical.Using MIME and choosing a content-transfer-encoding that quotes 'From_' lines in a standard-compliant fashion ensures that message content doesn't need to be changed, but only their MIME representation.Therefore checksums remain constant, a necessary precondition for supporting S/MIME and Pretty Good Privacy.Applications which newly create messages and store them in mbox database files will likely use this approach to detach message content from database storage format.
mboxo and mboxrd locate the message start by scanning for From lines that are found before the email message headers. If a 'From ' string occurs at the beginning of a line in either the header or the body of a message (a mail standard violation for the former, but not for the latter), the email message must be modified before the message is stored in an mbox mailbox file or the line will be taken as a message boundary.To avoid misinterpreting a 'From ' string at the beginning of the line in the email body as the beginning of a new email, some systems 'From-munge'[1]the message, typically by prepending a greater-than sign:
In the mboxo format, such lines have irreversible ambiguity.[2]In the mboxo format, this can lead to corruption of the message. If a line already contained >From at the beginning (such as in a quotation), it is unchanged when written. When subsequently read by the mail software, the leading > is erroneously removed. The mboxrd format solves this by converting From to >From and converting >From to >>From , etc. The transformation is then always reversible.[3]
Example:
The mboxcl and mboxcl2 formats use a Content-Length: header to determine the messages' lengths and thereby the next real From line. mboxcl still quotes From lines in the messages themselves as mboxrd does, while mboxcl2 doesn't.
Modified mbox[edit]
Some email clients use a modification of the mbox format for their mail folders.
- Eudora used an mboxo variation where a sender's email address is replaced by the constant string '???@???'. Most mbox clients store incoming messages as received. Eudora separates out attachments embedded in the message, storing the attachments as separate individual files in one folder.[4]
- The Mozilla family of email clients (Mozilla, Netscape, Thunderbird, et al.) use an mboxrd variation with more complex From line quoting rules.[5]
File locking[edit]
Various mutually incompatible mechanisms have been used by different mbox formats to enable message file locking, including fcntl() and lockf().This does not work well with network mounted file systems, such as the Network File System (NFS), which is why traditionally Unix used additional 'dot lock' files, which could be created atomically even over NFS.
Because more than one message is stored in a single file, some form of file locking is needed to avoid the corruption that can result from two or more processes modifying the mailbox simultaneously. This could happen if a network email delivery program delivers a new message at the same time as a mail reader is deleting an existing message.
Format Disk In Drive D
Mbox files should be locked also while they are being read. Otherwise the reader may see corrupted message contents if another process is modifying the mbox at the same time, even though no actual file corruption occurs.
As a patch format[edit]
In open source development, it is common to send patches in the diff format to a mailing list for discussion. The diff format allows for irrelevant 'headers', such as mbox data, to be added.[6][7]Version control systems like git have support for generating mbox-formatted patches and for sending them to the list as emails in a thread.[8][9]
See also[edit]
References[edit]
- ^RFC 3676 'The Text/Plain Format and DelSp Parameters'.Section 4.4: Space-Stuffing.2004.
- ^'Configuring Netscape Mail On Unix: Why the Content-Length Format is Bad'by Jamie Zawinski 1997
- ^de Boyne Pollard, Jonathan (2004). ''mbox' is a family of several mutually incompatible mailbox formats'. Frequently Given Answers.
- ^'Eudora 6.2.4 Mac User Guide'(PDF). p. 113. Archived from the original(PDF) on 2014-07-12. Retrieved 2015-10-29.
- ^'Importing and exporting your mail'
- ^'Submitting patches: the essential guide to getting your code into the kernel — The Linux Kernel documentation'. www.kernel.org.
- ^Randal, Allison; Sugalski, Dan; Tötsch, Leopold (2003). 'Patch submission'. Perl 6 Essentials. O'Reilly Media, Inc. p. 14. ISBN978-0-596-00499-6.
- ^'Git - git-format-patch Documentation'. git-scm.com.
- ^'Git - git-send-email Documentation'. git-scm.com.
Format Hard Drive And Reinstall Windows 10
Further reading[edit]
- Jonathan de Boyne Pollard (2004). ''mbox' is a family of several mutually incompatible mailbox formats'. Frequently Given Answers.
- Internet Mail Consortium – Standards body
- RFC 4155 – The application/mbox Media Type
