Jan 16, 2008 I have a.dmg (source image) that I have created from a DVD by myself (read-only format). I am trying to restore it to a destination and a Restore Failure notification pops-up as follow: 'Restore Failure Could not find any scan information. The source image needs to be imagescanned/scanned for restore' I am quite new to Mac.

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1. Unicase and Multicast: What's the Difference?

Image-based network deployment tools have long been considered the best way for administrators to roll out new workstations, deploy major operating system or application updates, or perform computer cleanup. By first configuring a workstation with all the requisite software and desired preferences and settings and then creating a disk image of that workstation, administrators can clone the original workstation across all similar computers within their company or institution. The disk image can be deployed to computers through any number of methods, but deploying it over the network is often the simplest and least time-consuming.

For Mac administrators, there are two major tools for network deployments: Apple Software Restore (ASR) and NetInstall. The differences between these tools are primarily in terms of how computers connect to and access the image. In the case of Apple's NetInstall, the computer actually loads and then runs the Mac OS X boot files, kernel, and installer application from the Mac OS X Server over the network. Once the Mac OS X installer runs, it deploys the NetInstall image, also hosted on the server, to the workstation's hard drive (with or without user interaction, as determined by the server administrator).

In the case of Apple Software Restore, the computer must be booted from a viable Mac OS X system disk, and the ASR command-line application (or a GUI interface to it) must be run, specifying the location of the image.

Unicase and Multicast: What's the Difference?

Until Mac OS X Tiger, both NetInstall and ASR required a separate connection between the server and each workstation accessing an image. This one-to-one access is referred to as a unicast network connection. For typical network access, unicast connections are ideal because the data sent from the server is destined only for a single computer. In an environment in which each network cable is connected to a port on a switch, the switch reads the destination of each packet of data from the server and forwards it only to the port where the appropriate workstation is located. This keeps the network from being congested with packets sent to every workstation (and for day-to-day network operation, it results in better network performance).

However, when doing large-scale deployments, a unicast approach creates a problem. As each workstation connects to the server to request the image, the server opens up a separate connection. Each connection takes server resources and requires bandwidth on the network. With each new workstation that requests the image, the available bandwidth resources get lower. Sooner or later, you get to a point where the transfer of image data to all connected workstations becomes noticeably slower with each new connection. If enough workstations connect, the progress of all of them can slow to a crawl. This can sometimes be most apparent with NetInstall, in which you can see not how long it takes for each workstation to receive image data but also how long it takes for each workstation to even boot to the installer application.

Exactly how many workstations can access a server-based image before you see a slowdown will vary depending on the type of workstations and the configuration of the server itself as well as the network over which the server and workstations are connecting. It's possible that as few as five Macs will be the best that a network and server will support (that is, you might find it faster to begin deploying the image to five Macs and wait until they're done before starting another five than to deploy six at a time). Even in optimal situations, you can see significant decreases once you start deploying an image to as few as 20 workstations.

Multicast Comes to Mac OS X

This is where Windows administrators performing network deployments have always had an advantage. Symantec Ghost, the Windows image-based deployment tool of choice, includes products that don't rely on unicast's one-to-one connection concept to transmit image data. Instead, the Enterprise version of Ghost uses a one-to-many approach known as multicast. A Ghost server sends the image as a constant stream of packets to all ports on a network segment. A computer simply needs to query the server to receive basic information about the image (the total size, data rate, image type, and beginning and end points of the stream, for example). Once the computer receives that information, it simply captures all the data in the stream and stores the data in the appropriate places between the endpoints on its hard drive. The result is that a great number of computers can receive the same image at once with no decrease in performance as each one begins to receive the image. Of course, this has the downside of decreasing performance on the network for any other purposes (sometimes to the point of it being essentially nonfunctional).

With Tiger, the situation for Mac administrators has changed dramatically because Apple has included support for multicast sessions in Apple Software Restore, meaning that it is now possible to deploy images to workstations without requiring each workstation to maintain a separate unicast connection to the server. As with Ghost, multicast ASR sessions allow the server hosting the image to stream the image across a network segment. When the ASR application is run from a workstation to be imaged, it downloads only the required information about the image (known as meta-data) and then connects to the stream. The server will repeat the stream indefinitely (beginning a new stream every five minutes), allowing workstations to jump in at any point and to pick up any pieces that they may miss as the stream repeats. When a workstation has received the entire image, it disconnects from the server. For the first time, it is possible for Mac administrators to perform massive deployments, such as that of all the eMacs in a high school, in a short time and in an efficient manner.

What may be even more exciting is that Apple includes ASR free with Mac OS X. This means that not only do Mac administrators get the performance advantages that go with multicast imaging, they get them without having to purchase an additional product or connection licenses (as is the case with Ghost). In fact, one doesn't even need Mac OS X Server. ASR is part of the client version of Mac OS X and can run on any Mac OS X Tiger computer. This is particularly helpful to administrators in a cross-platform environment that uses non-Apple servers (such as Windows 2000/2003 Server or Novell) and gives it a cost advantage over using Apple's NetInstall, which is part of Mac OS X Server, in such environments.

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Home > Articles > Apple > Operating Systems

1. Understanding System Image Creation

For many deployments, the best solution is a unified system disk image, which involves creating an ideal system, saving it to a disk image, and then deploying that system to all your computers. A unified system image requires a significant time investment up front, but it saves a great deal of time in the long run. Computers with identical configurations are much easier to manage; the fewer the differences between your deployed systems, the more uniform their performance and the less time spent diagnosing problems, updating software, and reconfiguring hardware.

A unified system image also greatly accelerates the deployment process for any deployment larger than a dozen computers. Once you have fully configured, tested, and created a custom system image on one computer, it can take as little as five minutes to copy it to another machine. Compare this with the time needed to deploy the system individually on every computer, and it’s easy to see the benefit of a deployable system disk image. In this chapter you will learn two general methods for creating deployable system disk images: cloning from a model system and building a modular system.

Understanding System Image Creation

Before starting the process of creating a system image, you must consider your deployment requirements: what software and configuration settings will be part of your system image? Consider your users, your systems, and the limitations of identical-system deployment on multiple computers. You also need to consider which of the two image creation methodologies will best suit your needs and abilities. The choices you make while planning your system image will affect every computer on which this system is deployed.

Defining System Image Requirements

When identifying all the specific items and configuration settings that you want to include in your system image, you must take into consideration the requirements of your users, the technical requirements of your systems, and the limitations of deploying an identical system on multiple computers.

User Requirements

Your primary focus when developing system image requirements should be on maximizing system usability, for both users and administrators. In some cases your target audience or usage policies may require tighter system control. This is often the case when users are inexperienced or cannot be trusted to manage any part of their systems. In this scenario you would limit application access and lock down as many system configuration settings as possible. You would also want to make things easy for the user by preconfiguring any system setting you can. In scenarios where you will be performing a significant amount of client management, you should incorporate directory services–based managed preferences.

In professional or creative environments, you may not need to be as restrictive in the application or settings, but you should still make sure to prepare the system based on the users’ needs; for instance, install third-party applications and peripheral drivers for inclusion with your system image.

No matter the level of your users, your system image should be as fully configured as possible, with both Apple and third-party software installed and updated, any necessary support files such as third-party drivers and fonts installed, and any systemwide configuration settings implemented. Note, though, that many settings are not well suited to deployment via a unified system image—more on this topic later in this section.

Computer-Specific System Requirements

Before you create your system image, you must determine which version of Mac OS X you intend to use. A major administrative advantage of using Mac OS X v10.6 and Mac OS X Server v10.6 is that they include all the hardware drivers necessary to work with any Mac that meets the minimum system requirements, allowing you to build a single system image that can work on any Mac.

Although creating a unified system image for computers that support Mac OS X v10.6 is simple, creating a system image for brand-new Macs can present a significant problem. In many cases, because the release of new Mac computers is not in sync with the release of the retail version of Mac OS X, a custom intermediate version of Mac OS X is created just to support the new hardware. However, new Macs cannot run versions of Mac OS X released prior to their introduction—that is, the oldest version of Mac OS X supported by a new Mac computer is the version that it ships with from the factory.

Thus, a previously created system image will not work on new Mac computers, and you will have to create a new system image based on the version of Mac OS X that shipped with the new Macs. Further, these custom intermediate versions of Mac OS X may technically work with older Mac computers, but they are not officially supported by Apple to do so, presenting a problem when you are trying to build a single unified system image.

How To Imagescan A Dmg System

Fortunately, every general Mac OS X version update includes support for all Mac computers introduced prior to the update. For example, if you were to acquire new Macs that were introduced this week, the next general update of Mac OS X will include support for those new Macs and will support older hardware as well. Therefore, if you can wait to build your system image until you can base it on the next general update for Mac OS X, you can create a single system image for all your Macs. If you can’t wait that long, you will need to create a separate system image just for your new Macs.

It’s important to note that custom intermediate versions of Mac OS X for new computers do not use different version numbers from the general releases. They do, however, have different build numbers, which can be identified by clicking once on the version number from the About This Mac window.

Software Update Requirements

You should strive to build your system image using the latest versions of your selected software. To do this, you’ll need to collect and keep track of all the necessary software update installers that you’ll apply when building your system image.

First you need to determine and acquire the latest version updates for Apple software. Apple’s downloads website, www.apple.com/downloads/, lists all the latest updates and can be searched and browsed so you can locate and then download specific Apple software updates. However, it may not seem obvious which Apple updates are needed; for this reason you can open Software Update from the Apple menu.

Apple Software Update will compare your Mac’s current installed software with the latest versions available from Apple. Obviously, you should run this on one of your test deployment systems to verify exactly which updates are necessary. The Mac OS X v10.6 version of Software Update no longer allows you to download updates without installing them. Thus, if you want to acquire the updates for later installation or deployment, you will have to do so from Apple’s downloads website.

You should also verify that you are using the latest versions of third-party applications and drivers. Many third-party products feature a built-in automatic update system that will check online for updates. However, few of these third-party update systems will allow you to download the individual update installer so that you can later use it to build your system image. Again, in this case, visit the software developer’s website to download the individual update installers.

Limitations of a Unified System Image

You should include as many configured settings as possible with your system image so you don’t have to spend time setting these items on each individual computer. However, there are many settings that you should not, or cannot, deploy with the same configuration to every computer.

For example, in most cases, user-specific settings should not be included with your system image. Computer-specific settings also should not be configured on the system image. For instance, a unique IP address and network name needs to be set for every Mac. Both user- and computer-specific settings are best handled using dedicated client management tools and techniques.

Apart from being ideal for, it can also burn a DMG file to USB to create a bootable drive. Since you haven't done any conversion, you can use this directly on a Mac for program installation, which you cannot do with the first method. How to burn dmg to disk. Launch the app and insert a USB drive into a free USB slot in your computer.Step 2: You can import the DMG file directly by clicking on ‘Burn' in the toolbar or going to Tools Burn. There are some settings that you have to keep in mind when burning with this software, but it's easy to get the hang of it once you do it a couple of times.Step 1: Download PowerISO and install it in your Windows PC. Part 3: Create Bootable USB from DMG in Windows Via PowerISOAnother well-known disk image utility is PowerISO.

In deploying a Mac OS X Server system image, your primary goal will be to strike a balance between what you can safely configure as part of the generic server system image and what settings you must leave for after deployment.

Choosing a System Image Methodology

When using the tools built into Mac OS X to create a deployable system disk image, you have a choice between two different methodologies: cloned system images and modular system images.

With a cloned system image, you first set up a model computer that is configured with all the software and settings you intend to deploy. Then you create a duplicate copy of the system volume saved to a disk image that has been specially prepared for deployment.

The modular system image methodology, a newer method, requires a bit more work up front, but it has several advantages over the older method and is the Apple-recommended best practice. With this method you build a fresh system by installing a series of installation packages to a sparse disk image. The installations include the full Mac OS X system, any software updates, any additional Apple software, any third-party software, and any custom installation packages that you have created to set up your system image. This sparse image is then converted to a disk image that has been prepared for deployment.

Cloned System Image Pros and Cons

• Pro—Easier workflow for novice administrators

• Pro—Less time spent creating initial system images

• Con—Requires that the model computer be purged of any unnecessary or troublesome files

• Con—Prone to issues if model not properly “cleaned”

• Con—Prone to more issues when deploying to different models

• Con—Increased workload when creating multiple system images

• Con—Increased workload when it’s time to update system images

  There are a few things to consider before trying to install MySQL on El Capitan (MacOS 10.11) The latest stable version when you use a.dmg for this OS is mysql-5.6.27-osx10.11-x8664 and maybe that's why clockgettime symbol is missing when you symlink mysql-5.7.22-1. Why i cannot open mysql dmg in mac version. Whether you are an avid Mac programmer using a Windows PC, or you just found a DMG file on your Windows machine, it can be useful to know what it is and how to open it. Luckily it’s easy to open on Windows if you know how. Sep 21, 2007  How to Install Software from DMG Files on a Mac. 21 September, 2007 by Tom Harrison in mac os x. A.DMG file is a container file commonly used to distribute applications for Mac OS X. Installing software from one of these requires you to mount the image and move its contents to your computer’s “Applications” directory. I downloaded the mysql dmg file and went through the wizard to run. I have also started mysql server under system preferences. Mac install and open mysql using terminal. Ask Question Asked 7 years. Then close terminal and open a new terminal and type. Mysql -u root -p hit enter, and it will ask you for password.

• Con—New system images are never consistent with prior images

• Con—Difficult to document and audit system image configurations

• Con—Increased workload to test system image modifications

Modular System Image Pros and Cons

• Pro—System images are clean because they have never been booted.

• Pro—System images have no model-specific settings.

• Pro—Apple updates won’t interfere with your customizations because they are always applied before your customizations.

• Pro—Your workload is lighter when creating multiple system images that require unique software and configurations.

• Pro—Your workload is decreased when it’s time to update system images.

• Pro—Multiple and updated system images are perfectly consistent for similar items every single time.

• Pro—All configurations are easily documented and easily audited.

• Pro—Testing of updates and image modifications are simpler.

• Pro—System image creation process is automated.

• Pro—It’s easy to integrate modular system images with system maintenance workflows and third-party deployment tools.

• Con—Workflow is more difficult for novice administrators.

• Con—You must create custom installation packages for some third-party items and any configuration settings.

• Con—You will spend more time creating an initial system image.

The cloned system image methodology requires less effort up front, and you can get your first image set up quickly. However, in the long run you’ll have to spend much more time fixing bugs, updating software, and adding modifications than with a modular system image. The modular system image methodology requires more initial effort to properly configure your first system image, but maintaining your systems will be much easier because you’ll be able to build new modular images with additional items and updated software.

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