System Deployment Image

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A System Deployment Image (aka SDI) is a file format used primarily with Microsoft products to contain an arbitrary disk image, including boot sector information.

Microsoft U.S.-headquartered technology company

Microsoft Corporation (MS) is an American multinational technology company with headquarters in Redmond, Washington. It develops, manufactures, licenses, supports and sells computer software, consumer electronics, personal computers, and related services. Its best known software products are the Microsoft Windows line of operating systems, the Microsoft Office suite, and the Internet Explorer and Edge web browsers. Its flagship hardware products are the Xbox video game consoles and the Microsoft Surface lineup of touchscreen personal computers. As of 2016, it is the world's largest software maker by revenue, and one of the world's most valuable companies. The word "Microsoft" is a portmanteau of "microcomputer" and "software". Microsoft is ranked No. 30 in the 2018 Fortune 500 rankings of the largest United States corporations by total revenue.

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 usually made by creating a sector-by-sector copy of the source medium, thereby perfectly 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.

Contents

Description

The System Deployment Image (SDI) file format is often used to allow the use of a virtual disk for startup or booting. Some versions of Microsoft Windows allow for "RAM booting", which is essentially the ability to load an SDI file into memory and then boot from it. The SDI file format also lends itself to network booting using the Preboot Execution Environment (PXE). Another usage is hard disk imaging. The SDI file itself is partitioned into the following sections:

Microsoft Windows is a group of several graphical operating system families, all of which are developed, marketed, and sold by Microsoft. Each family caters to a certain sector of the computing industry. Active Windows families include Windows NT and Windows Embedded; these may encompass subfamilies, e.g. Windows Embedded Compact or Windows Server. Defunct Windows families include Windows 9x, Windows Mobile and Windows Phone.

In computing, booting is starting up a computer or computer appliance until it can be used. It can be initiated by hardware such as a button press or by software command. After the power is switched on, the computer is relatively dumb and can read only part of its storage called read-only memory (ROM). There, a small program is stored called firmware. It does power-on self-tests and, most importantly, allows accessing other types of memory like a hard disk and main memory. The firmware loads bigger programs into the computer's main memory and runs it. In general purpose computers, but additionally in smartphones and tablets, optionally a boot manager is run. The boot manager lets a user choose which operating system to run and set more complex parameters for it. The firmware or the boot manager then loads the boot loader into the memory and runs it. This piece of software is able to place an operating system kernel like Windows or Linux into the computer's main memory and run it. Afterwards, the kernel runs so-called user space software – well known is the graphical user interface (GUI), which lets the user log in to the computer or run some other applications. The whole process may take seconds to tenths of seconds on modern day general purpose computers.

Preboot Execution Environment Preboot Execution Environment

In computing, the Preboot eXecution Environment specification describes a standardized client-server environment that boots a software assembly, retrieved from a network, on PXE-enabled clients. On the client side it requires only a PXE-capable network interface controller (NIC), and uses a small set of industry-standard network protocols such as DHCP and TFTP.

Boot BLOB  
This contains the actual boot program, STARTROM.COM. This is analogous to the boot sector of a hard disk.
Load BLOB 
This typically contains NTLDR and is launched by the boot BLOB.
Part BLOB 
This contains the actual boot runtime (i.e. the contents of the disk image including any Operating System [OS] files) and also includes the boot.ini (used by NTLDR) and ntdetect.com files which should be located within the root directory of the runtime. The size of the runtime cannot exceed 500 MB. In addition to this requirement the runtime must also be capable of dealing with the fact that it is booting from a ramdisk. This implies that the runtime must include the "Windows RAM Disk Driver" component (specified within the boot.ini).
Disk BLOB 
This is flat HDD image starting with a MBR. It is used for hard drive imaging instead of booting. Also only Disk BLOBs can be mounted with Microsoft's utilities.

SDI usually contains either Disk BLOB (HD cloning or temporary SDI) or three other of them (bootable SDI).

Windows Vista or Windows PE 2.0 boot sequence includes a boot.sdi file, which contains Part BLOB for an empty NTFS volume and a Table-of-Contents slot for the WIM image, which is stored on a separate on-disk file.

Windows Vista personal computer operating system by Microsoft released in 2006

Windows Vista is an operating system that was produced by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs and media center PCs. Development was completed on November 8, 2006, and over the following three months, it was released in stages to computer hardware and software manufacturers, business customers and retail channels. On January 30, 2007, it was released worldwide and was made available for purchase and download from the Windows Marketplace; it is the first release of Windows to be made available through a digital distribution platform. The release of Windows Vista came more than five years after the introduction of its predecessor, Windows XP, the longest time span between successive releases of Microsoft Windows desktop operating systems.

Windows Preinstallation Environment lightweight version of Microsoft Windows for deployment

Windows Preinstallation Environment is a lightweight version of Windows used for the deployment of PCs, workstations, and servers, or troubleshooting an operating system while it is offline. It is intended to replace MS-DOS boot disks and can be booted via USB flash drive, PXE, iPXE, CD-ROM, or hard disk. Traditionally used by large corporations and OEMs, it is now widely available free of charge via Windows Automated Installation Kit (WAIK).

NTFS is a proprietary file system developed by Microsoft. Starting with Windows NT 3.1, it is the default file system of the Windows NT family.

SDI features

SDI driver

SDI files can be mounted as virtual disk drives and assigned a drive letter if an SDI driver is available to allow this. A SDI driver is a type of storage driver and is commonly used with Windows XP Embedded.

SDI management

Microsoft provides a tool called the "SDI File Manager" (sdimgr.exe) which can be used for the purpose of manipulating SDI files. Some of the tasks which this tool facilitates are:

SDI loader

The mechanism which allows for the creation, addition and removal of virtual disk drives. SDI Loader and Driver work with Disk BLOB.

See also

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Windows 9x

Windows 9x is a generic term referring to a series of Microsoft Windows computer operating systems produced from 1995 to 2000, which were based on the Windows 95 kernel and its underlying foundation of MS-DOS, both of which were updated in subsequent versions. This includes all versions of Windows 95 and Windows 98. Windows ME is sometimes included.

Multi-booting

Multi-booting is the act of installing multiple operating systems on a computer, and being able to choose which one to boot. The term dual-booting refers to the common configuration of specifically two operating systems. Multi-booting may require a custom boot loader.

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Diskless node

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EasyBCD

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In computing, diskpart is a command-line disk partitioning utility included in Windows 2000 and later, replacing its predecessor, fdisk.

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Architecture of Windows 9x

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