Misplaced Pages

#776223

40-415: Like other disk image formats, a WIM file contains a set of files and associated filesystem metadata . However, unlike sector -based formats (such as ISO or VHD ), WIM is file-based: the fundamental unit of information in a WIM is a file. The primary advantages of being file-based is hardware independence and single-instance storage of a file referenced multiple times in the filesystem tree. Since

80-587: A CD/DVD drive by reading an ISO image . This can also be faster than reading from the physical optical medium. Further, there are less issues with wear and tear. A hard disk drive or solid-state drive in a virtual machine is implemented as a disk image (i.e. either the VHD format used by Microsoft's Hyper-V , the VDI format used by Oracle Corporation 's VirtualBox , the VMDK format used for VMware virtual machines, or

120-473: A POSIX compatibility layer and are not otherwise inherently Unix systems. Many ancient UNIX systems no longer meet this definition. Broadly, any Unix-like system that behaves in a manner roughly consistent with the UNIX specification, including having a " program which manages your login and command line sessions "; more specifically, this can refer to systems such as Linux or Minix that behave similarly to

160-470: A UNIX system but have no genetic or trademark connection to the AT&;T code base. Most free/open-source implementations of the UNIX design, whether genetic UNIX or not, fall into the restricted definition of this third category due to the expense of obtaining Open Group certification, which costs thousands of dollars. Around 2001 Linux was given the opportunity to get a certification including free help from

200-502: A Windows Installation CD or Windows Update . Before Windows Server 2012 and Windows 8, DISM had incorporated the majority of ImageX functions but not all; ImageX was still needed for image capture and applying. However, DISM deprecated ImageX in Windows 8. Windows 8.1 added ability to apply and capture disk images, and Windows 10 extended image applying, by adding compression. Since April 30, 2012, an open-source library for handling

240-406: A bit-by-bit copy to ensure forensic soundness. The purposes of imaging the disk is to not only discover evidence preserved in digital information but also to examine the drive to gather clues of how the crime was committed. Creating a virtual disk image of optical media or a hard disk drive is typically done to make the content available to one or more virtual machines . Virtual machines emulate

280-614: A bootable version of Windows PE from which the installation is performed. Other setup files are held in the INSTALL.WIM. Since Windows 8.1 , the size of Windows directory can be reduced by moving system files into compressed WIM images stored on a separate hidden partition ( WIMBoot ). Since Windows 10 , system files can be compressed on the system disk ( CompactOS ). WIM supports three families of LZ77 -based compression algorithms in ascending ratio and descending speed: XPRESS, LZX , and LZMS. The former two use Huffman encoding , while

320-539: A computer. This is usually used in conjunction with a DHCP server to automate the configuration of network parameters including IP addresses. Multicasting , broadcasting or unicasting tend to be used to restore an image to many computers simultaneously. These approaches do not work well if one or more computers experience packet loss. As a result, some imaging solutions use the BitTorrent protocol to overcome this problem. Network-based image deployment reduces

360-596: A historical connection to the AT&;T codebase. Most commercial UNIX systems fall into this category. So do the BSD systems, which are descendants of work done at the University of California, Berkeley in the late 1970s and early 1980s. Some of these systems have no original AT&T code but can still trace their ancestry to AT&T designs. These systems‍—‌largely commercial in nature‍—‌have been determined by

400-873: A misuse of their trademark. Their guidelines require "UNIX" to be presented in uppercase or otherwise distinguished from the surrounding text, strongly encourage using it as a branding adjective for a generic word such as "system", and discourage its use in hyphenated phrases. Other parties frequently treat "Unix" as a genericized trademark . Some add a wildcard character to the name to make an abbreviation like "Un*x" or "*nix", since Unix-like systems often have Unix-like names such as AIX , A/UX , HP-UX , IRIX , Linux , Minix , Ultrix , Xenix , and XNU . These patterns do not literally match many system names, but are still generally recognized to refer to any UNIX system, descendant, or work-alike, even those with completely dissimilar names such as Darwin / macOS , illumos / Solaris or FreeBSD . In 2007, Wayne R. Gray sued to dispute

440-455: A single disk. In some cases, disk imaging can fail due to bad sectors or physical wear and tear on the source device. Unix utilities (such as dd ) are not designed to cope with failures, causing the disk image creation process to fail. When data recovery is the end goal, it is instead recommended to use more specialised tools (such as ddrescue ). Unix-like A Unix-like (sometimes referred to as UN*X or *nix ) operating system

SECTION 10

#1732780067777

480-487: A variety of formats depending on the purpose. Virtual disk images (such as VHD and VMDK) are intended to be used for cloud computing, ISO images are intended to emulate optical media and raw disk images are used for forensic purposes. Proprietary formats are typically used by disk imaging software. Despite the benefits of disk imaging the storage costs can be high, management can be difficult and they can be time consuming to create. Disk images were originally (in

520-486: A variety of proprietary systems were developed based on it, including AIX , HP-UX , IRIX , SunOS , Tru64 , Ultrix , and Xenix . These largely displaced the proprietary clones. Growing incompatibility among these systems led to the creation of interoperability standards, including POSIX and the Single UNIX Specification . Various free, low-cost, and unrestricted substitutes for UNIX emerged in

560-644: A virtual disk image. A virtual burner, by definition, appears as a disc drive in the system with writing capabilities (as opposed to conventional disc authoring programs that can create virtual disk images), thus allowing software that can burn discs to create virtual discs. Forensic imaging is the process of creating a bit-by-bit copy of the data on the drive, including files, metadata, volume information, filesystems and their structure. Often, these images are also hashed to verify their integrity and that they have not been altered since being created. Unlike disk imaging for other purposes, digital forensic applications take

600-450: Is a tool introduced in Windows 7 and Windows Server 2008 R2 that can perform servicing tasks on a Windows installation image, be it an online image (i.e. the one the user is running) or an offline image within a folder or WIM file. Its features include mounting and unmounting images, querying installed device drivers in an offline image, and adding a device driver to an offline image. It is now possible to repair with DISM any image using either

640-550: Is distributed as part of the free Windows Automated Installation Kit (WAIK/OPK). Starting with Windows Vista , Windows Setup uses the WAIK API to install Windows. The first distributed prototype of ImageX was built 6.0.4007.0 (main.030212-2037). It allowed Microsoft OEM partners to experiment with the imaging technology and was developed in parallel with Longhorn alpha prototypes. It was first introduced in Milestone 4 into

680-550: Is made up of many small, interchangeable components that can be added or removed as needed. This makes it easy to customize the operating system to suit the needs of different users or environments. The Open Group owns the UNIX trademark and administers the Single UNIX Specification, with the "UNIX" name being used as a certification mark . They do not approve of the construction "Unix-like", and consider it

720-419: Is now common to only copy allocated data to reduce storage space. Compression and deduplication are commonly used to reduce the size of the image file set. Disk imaging is done for a variety of purposes including digital forensics , cloud computing , system administration , as part of a backup strategy, and legacy emulation as part of a digital preservation strategy. Disk images can be made in

760-405: Is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification . A Unix-like application is one that behaves like the corresponding Unix command or shell . Although there are general philosophies for Unix design, there is no technical standard defining the term, and opinions can differ about

800-513: Is still possible to convert .wim images to the more commonly used ISO image using the Windows Assessment and Deployment Kit on Windows. Disk image A disk image is a snapshot of a storage device's structure and data typically stored in one or more computer files on another storage device. Traditionally, disk images were bit-by-bit copies of every sector on a hard disk often created for digital forensic purposes, but it

840-418: Is their ability to support multiple users and processes simultaneously. This allows users to run multiple programs at the same time and to share resources such as memory and disk space. This is in contrast to many older operating systems, which were designed to only support a single user or process at a time. Another important feature of Unix-like systems is their modularity . This means that the operating system

SECTION 20

#1732780067777

880-453: Is used to create an image of a completely-configured system (such an image is sometimes called a golden image). This image is then written to a computer's hard disk (which is sometimes described as restoring an image). Image restoration can be done using network-based image deployment. This method uses a PXE server to boot an operating system over a computer network that contains the necessary components to image or restore storage media in

920-484: Is usually simpler to program than accessing a real floppy drive (particularly if the disks are in a format not supported by the host operating system), and allows a large library of software to be managed. Emulation also allows existing disk images to be put into a usable form even though the data contained in the image is no longer readable without emulation. Disk imaging is time consuming, the space requirements are high and reading from them can be slower than reading from

960-530: The Open Group to meet the Single UNIX Specification and are allowed to carry the UNIX name. Most such systems are commercial derivatives of the System V code base in one form or another, although Apple macOS 10.5 and later is a BSD variant that has been certified, and EulerOS and Inspur K-UX are Linux distributions that have been certified. A few other systems (such as IBM z/OS) earned the trademark through

1000-506: The QCOW format used by QEMU ). Virtual hard disk images tend to be stored as either a collection of files (where each one is typically 2GB in size), or as a single file. Virtual machines treat the image set as a physical drive. Educational institutions and businesses can often need to buy or replace computer systems in large numbers. Disk imaging is commonly used to rapidly deploy the same configuration across workstations. Disk imaging software

1040-479: The dd program can be used to create raw disk images. Apple Disk Copy can be used on Classic Mac OS and macOS systems to create and write disk image files. Authoring software for CDs/DVDs such as Nero Burning ROM can generate and load disk images for optical media. A virtual disk writer or virtual burner is a computer program that emulates an actual disc authoring device such as a CD writer or DVD writer. Instead of writing data to an actual disc, it creates

1080-514: The 1980s and 1990s, including 4.4BSD , Linux , and Minix . Some of these have in turn been the basis for commercial "Unix-like" systems, such as BSD/OS and macOS . Several versions of (Mac) OS X/macOS running on Intel-based Mac computers have been certified under the Single UNIX Specification . The BSD variants are descendants of UNIX developed by the University of California at Berkeley, with UNIX source code from Bell Labs . However,

1120-542: The BSD code base has evolved since then, replacing all the AT&T code. Since the BSD variants are not certified as compliant with the Single UNIX Specification, they are referred to as "UNIX-like" rather than "UNIX". Dennis Ritchie , one of the original creators of Unix, expressed his opinion that Unix-like systems such as Linux are de facto Unix systems. Eric S. Raymond and Rob Landley have suggested that there are three kinds of Unix-like systems: Those systems with

1160-467: The Longhorn project and used in later builds of Longhorn. Build 6.0.5384.4 added significant advantages over previous versions, like read-only and read/write folder mounting capabilities, splitting to multiple image files (SWM), a WIM filter driver and the latest compression algorithms. It has been used since pre-RC (release candidates) of Windows Vista. Deployment Image Service and Management Tool (DISM)

1200-544: The WIM format is available. This library can be used on Unix-like systems, as well as on Windows. Thanks to this project, Linux distributions now have their own imagex clone called wimlib-imagex , which allows mounting WIM images and managing them (read/write) like any other block-storage provider. As WIM images use somewhat common compression algorithms, they can be accessed by using file archivers like 7-Zip . For other operating systems that might not support this format, it

1240-501: The case of copy protected floppy disks. Disk image creation is called disk imaging and is often time consuming, even with a fast computer, because the entire disk must be copied. Typically, disk imaging requires a third party disk imaging program or backup software. The software required varies according to the type of disk image that needs to be created. For example, RawWrite and WinImage create floppy disk image files for MS-DOS and Microsoft Windows . In Unix or similar systems

Windows Imaging Format - Misplaced Pages Continue

1280-536: The degree to which a particular operating system or application is Unix-like. Some well-known examples of Unix-like operating systems include Linux and BSD . These systems are often used on servers as well as on personal computers and other devices. Many popular applications, such as the Apache web server and the Bash shell, are also designed to be used on Unix-like systems. One of the key features of Unix-like systems

1320-630: The disk directly because of a performance overhead. Other limitations can be the lack of access to software required to read the contents of the image. For example, prior to Windows 8, third party software was required to mount disk images. When imaging multiple computers with only minor differences, much data is duplicated unnecessarily, wasting space. Disk imaging can be slow, especially for older storage devices. A typical 4.7 GB DVD can take an average of 18 minutes to duplicate. Floppy disks read and write much slower than hard disks. Therefore, despite their small size, it can take several minutes to copy

1360-446: The exact and efficient recovery after experimenting with modifications to a system or virtual machine . Typically, disk imaging can be used to quickly restore an entire system to an operational state after a disaster. Libraries and museums are typically required to archive and digitally preserve information without altering it in any manner. Emulators frequently use disk images to emulate floppy disks that have been preserved. This

1400-444: The files are stored inside a single WIM file, the overhead of opening and closing many individual files is reduced. The cost of reading or writing many thousands of individual files on the local disk is negated by hardware and software-based disk caching as well as sequential reading and writing of the data. WIM files can contain multiple disk images, which are referenced either by their numerical index or by their unique name. Due to

1440-408: The late 1960s) used for backup and disk cloning of mainframe disk media. Early ones were as small as 5 megabytes and as large as 330 megabytes, and 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, especially in

1480-549: The latter uses adaptive Huffman encoding with range coding . There is also support for solid compression . Both solid compression and LZMS are introduced more recently, in WIMGAPI from Windows 8 and DISM from Windows 8.1. ImageX is the command-line tool used to create, edit and deploy Windows disk images in the Windows Imaging Format. Along with the underlying Windows Imaging Interface library (WIMGAPI), it

1520-416: The need to maintain and update individual systems manually. Imaging is also easier than automated setup methods because an administrator does not need to have knowledge of the prior configuration to copy it. A disk image contains all files and data (i.e., file attributes and the file fragmentation state). For this reason, it is also used for backing up optical media ( CDs and DVDs , etc.), and allows

1560-508: The status of UNIX as a trademark, but lost his case, and lost again on appeal, with the court upholding the trademark and its ownership. "Unix-like" systems started to appear in the late 1970s and early 1980s. Many proprietary versions, such as Idris (1978), UNOS (1982), Coherent (1983), and UniFlex (1985), aimed to provide businesses with the functionality available to academic users of UNIX. When AT&T allowed relatively inexpensive commercial binary sublicensing of UNIX in 1979,

1600-516: The use of single-instance storage, the more each successive disk image has in common with previous images added to the WIM file, the less new data will be added. A WIM can also be split (spanned) into multiple parts, which have the .swm extension. WIM images can be made bootable and Windows boot loader supports booting Windows from a WIM file. Windows Setup DVD in Windows Vista and later use such WIM files. In this case, BOOT.WIM contains

#776223