Disk image

A disk image, in computing, is a computer file containing the contents and structure of a disk volume or of an entire data storage device, such as a hard disk drive, tape drive, floppy disk, optical disc, or USB flash drive. A disk image is made by creating a sector-by-sector copy of the source medium, thereby replicating the structure and contents of a storage device independent of the file system. Depending on the disk image format, a disk image may span one or more computer files; the file format may be an open standard, such as the ISO image format for optical disc images, or a disk image may be unique to a particular software application. The size of a disk image can be large. To reduce storage requirements, if an imaging utility is filesystem-aware it can omit copying unused space, it can compress the used space. Disk images were used for backup and disk cloning of mainframe disk media; the early ones were as small as 5 megabytes and as large as 330 megabytes, the copy medium was magnetic tape, which ran as large as 200 megabytes per reel.

Disk images became much more popular when floppy disk media became popular, where replication or storage of an exact structure was necessary and efficient in the case of copy protected floppy disks. Disk images are used for duplication of optical media including Blu-ray discs, etc.. It is used to make perfect clones of hard disks. A virtual disk may emulate any type of physical drive, such as a hard disk drive, tape drive, key drive, floppy drive, CD/DVD/BD/HD DVD, or a network share among others. An emulated drive is created either in RAM for fast read/write access, or on a hard drive. Typical uses of virtual drives include the mounting of disk images of CDs and DVDs, the mounting of virtual hard disks for the purpose of on-the-fly disk encryption; some operating systems such as Linux and macOS have virtual drive functionality built-in, while others such as older versions of Microsoft Windows require additional software. Starting from Windows 8, Windows includes native virtual drive functionality.

Virtual drives are read-only, being used to mount existing disk images which are not modifiable by the drive. However some software provides virtual CD/DVD drives. Using disk images in a virtual drive allows users to shift data between technologies, for example from CD optical drive to hard disk drive; this may provide advantages such as noise. In addition it may reduce power consumption, since it may allow just one device to be used instead of two. Virtual drives may be used as part of emulation of an entire machine. Since the spread of broadband, CD and DVD images have become a common medium for Linux distributions. Applications for macOS are delivered online as an Apple Disk Image containing a file system that includes the application, documentation for the application, so on. Online data and bootable recovery CD images are provided for customers of certain commercial software companies. Disk images may be used to distribute software across a company network, or for portability. There are several types of software that allow software to be distributed to large numbers of networked machines with little or no disruption to the user.

Some can be scheduled to update only at night so that machines are not disturbed during business hours. These technologies reduce end-user impact and reduce the time and man-power needed to ensure a secure corporate environment. Efficiency is increased because there is much less opportunity for human error. Disk images may be needed to transfer software to machines without a compatible physical disk drive. For computers running macOS, disk images are the most common file type used for software downloads downloaded with a web browser; the images are compressed Apple Disk Image files. They are opened by directly mounting them without using a real disk; the advantage compared with some other technologies, such as Zip and RAR archives, is they do not need redundant drive space for the unarchived data. Software packages for Windows are sometimes distributed as disk images including ISO images. While Windows versions prior to Windows 7 do not natively support mounting disk images to the files system, several software options are available to do this.

Virtual hard disks are used in on-the-fly disk encryption software such as FreeOTFE and TrueCrypt, where an encrypted "image" of a disk is stored on the computer. When the disk's password is entered, the disk image is "mounted", made available as a new volume on the computer. Files written to this virtual drive are written to the encrypted image, never stored in cleartext; the process of making a computer disk available for use is called "mounting", the process of removing it is called "dismounting" or "unmounting". A hard disk image is interpreted by a Virtual Machine Monitor as a system administrator using terms of naming, a hard disk image for a certain Virtual Machine monitor has a specific file. Hard dri

List of terrorist incidents in 1992

This is a timeline of incidents in 1992 that have been labelled as "terrorism" and are not believed to have been carried out by a government or its forces. To be included, entries must be notable and described by a consensus of reliable sources as "terrorism". List entries must comply with the guidelines outlined in the manual of style under MOS:TERRORIST. Casualty figures in this list are the total casualties of the incident including immediate casualties and casualties. Casualties listed are the victims. Perpetrator casualties are listed separately. Casualty totals may be unavailable due to a lack of information. A figure with a plus sign indicates that at least that many people have died – the actual toll could be higher. A figure with a plus sign may indicate that over that number of people are victims. If casualty figures are 20 or more, they will be shown in bold. In addition, figures for casualties more than 50 will be underlined. Incidents are limited to one per location per day. If multiple attacks occur in the same place on the same day, they will be merged into a single incident.

In addition to the guidelines above, the table includes the following categories: List of terrorist incidents

Jesús Parejo

Jesús Parejo is a Venezuelan former track and field athlete who competes in the shot put and discus throw. He holds 57.58 m for those events. His greatest achievements were a discus silver medal at the 2010 Central American and Caribbean Games and bronze medals at the 2011 South American Championships in Athletics and 2008 Central American and Caribbean Championships in Athletics, he represented his country at the 2011 Pan American Games, 2011 Military World Games, the 2014 South American Games, was a three-time participant at the Ibero-American Championships in Athletics. He was a medallist at three straight editions of ALBA Games. A five-time national champion, he was Venezuela's top discus thrower from around 2005 to 2014, following on from Héctor Hurtado. Shot put – 17.56 m Discus throw – 57.58 m Hammer throw – 59.32 m All information from All-Athletics profile. Jesús Parejo at World Athletics