Creating OS X Mavericks Install Media

mavericksIT staff, and even consumers often want to have a physical bootable install disk for OS X.  In OS X Mavericks, Apple have provided a relatively simple command line tool for creating bootable install media.

To create the install media, mount a volume that you would like to use as an install disk.  This volume needs to be able to hold at least 5.36 GB of data to house the install media. Note that this volume will be erased and reconfigured as an OS X installer. With the desired volume mounted, open the Terminal application and execute the following command:

sudo /Applications/Install OS X Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/TargetVolumeName --applicationpath /Applications/Install OS X Mavericks.app --nointeraction

Replace “TargetVolumeName” with the name of the volume you want to turn into a bootable OS X Mavericks installation disk.

See the screenshot below for the Terminal output from the command above.

Mavericks Installer Creation
Mavericks Installer Creation

The Right OS For The Right Mac

macfamily-promo-osx-family-icon_2xA perennial topic of discussion amongst Mac system administrators is which operating system should be deployed to which Mac.  There is a mountain of misinformation floating around the community and the Internet on this topic. Here, I hope to set a few things straight.

On any particular Mac, the earliest version of OS X supported by Apple is the version that shipped with the Mac in question. Installing an earlier version of OS X will either fail to install, fail to boot after installation, or cause unexpected issues after boot. Regardless of how well the install goes or whether or not the computer boots, Apple will not support this configuration. Answers to support requests will generally amount to “install the correct operating system”. See the link below for Apple’s notes on this topic and a list of which OS X versions shipped with each Mac computer (note, as of this writing, the chart has not been updated to include 2013 iMac models).
http://support.apple.com/kb/HT1159

An Open Secret

It is widely held in the Mac sysadmin community that once Apple releases a new version of OS X, this new version includes the software components necessary to support the new OS X version on earlier hardware.

There are two situations in which this generally applies.

  1. An OS X installation that has had an update applied bearing the suffix “(Combo)”, as in “OS X Mountain Lion Update v10.8.5 (Combo)”, will usually support all hardware released prior to the update that meets the system requirements for the major OS X release, OS X Mountain Lion v10.8 in this example.
  2. The apps “Install Mac OS X Lion.app”, “Install OS X Mountain Lion.app” and soon, “Install OS X Mavericks.app”, from the Mac App Store will install OS X on any Mac computer released prior the latest update to the OS X installer app used.

I call this an “open secret” because you will find nothing in Apple’s documentation to support this claim, however it is generally correct.  I say “generally correct”, because occasionally it isn’t, particularly when hardware and OS X releases come close together.

The only 100% certain way to ensure an OS X installation is appropriate for and supported on a Mac computer is to use the OS X installer supplied by Apple for the computer in question, which includes a factory-installed Recovery System (Recovery HD) and OS X Internet Recovery.  See the link below for Apple’s explanation of OS X Recovery:
http://support.apple.com/kb/HT4718

OS X Hacking

There are those in the community who, for various reasons, hack new releases of OS X, and insert components from the new release into a previous release in an effort to run an earlier operating system than Apple intended or supports on a particular Mac.  The people doing this are clever and deserving of “geek cred”, but I would never recommend using such a hacked distribution in a production environment.

Running a “hacked operating system” may run afoul of the organization’s operating rules either self-imposed or legally required.  Even in the absence of such restrictions, my recommendation stands.  Vendor support is a key component in service level agreements.  If you choose to deploy an OS with unsupported modifications, you are ultimately personally responsible for every system failure.  This is not a position I want to be in or that I recommend you place yourself in.

Understanding New Software With Old Batteries

batteriesI’ve come across lots of tweets, blog posts, and in-person comments regarding battery life on older devices after having upgraded to iOS 7.  While I know many people simply enjoy complaining, perhaps a dose of knowledge will help ease misguided anger.

There are two primary factors in the degradation of lithium-ion batteries.  The first is charge cycles. Apple rates iPhone batteries at 400 charge cycles.1 An iPhone battery that has been recharged more than 400 times will experience decreased performance. Second, these batteries have an expiration date. The useful life of a lithium-ion battery is two to three years, even if it goes through zero charge cycles.2 The battery in an iPhone 4s purchased at launch in October 2011 has likely reached the end of its usable life.

iOS 7 was launched alongside new iPhone models with improved batteries. New, more power-intensive features were likely developed with the new battery technology in mind. Older devices not only have previous generation battery technology, but those batteries are approaching, if not already past, their usable life cycle.

If you’re not ready to upgrade your device, but your battery has exceeded its usable life in charge cycles, age, or both, You can purchase a new battery at an Apple Store or Apple Authorized Service Provider.

1: http://www.apple.com/batteries/iphone.html
2: http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery2.htm

Resetting AirPlay

AirplayIconI have been having occasions lately where I’ll lose audio whilst using AirPlay mirroring from my Mac running OS X version 10.8.4 to my Apple TV running the latest Apple TV Software, version 5.3.  When this issue occurs, audio from iTunes, Hulu, Netflix, etc. on the Apple TV plays audio normally, as does AirPlay content from an iOS device.  It seems to be only OS X devices that are affected.  Searches of Apple support forums and other places Mac nerds share information showed that this is not an issue peculiar to my equipment.

I have reported the issue to Apple, as I’m sure others have, and will continue to investigate on my own to see if I can uncover a specific cause and more finely tuned fix.  In the meantime, forcing Core Audio on the Mac to restart seems to solve the problem, at least temporarily.  Use the following command to stop Core Audio, which will then automatically restart.

sudo killall coreaudiod

I’ve also bundled this into an Automator application, if that makes things a bit easier for some.  It will prompt for administrative credentials when launched.

Download Restart coreaudiod

Note: Restart coreaudiod is provided “as is” without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability, or fitness for a particular purpose.

 

IPSW File Primer

ipswBecause I have been asked a few times, here’s some basic information about IPSW files used by iOS devices for a short Friday post.

IPSW files (iPod Software) are the files used by iTunes, Apple Configurator, and Xcode to restore or update an iOS device’s firmware.  This includes the iOS operating system and the built-in apps.  These files are compressed archives and can be downloaded manually from Apple’s iOS Dev Center, or automatically using iTunes or Apple Configurator.  Once updated, there is no Apple-supported method for downgrading iOS on a device.

There is a different .ipsw file for each iOS version and device model.  For example, an iPhone 5, iPad Mini Wi-Fi, iPad Mini Wi-Fi + Cellular, and a 4th Generation iPod Touch can all run iOS 6.1.2, but they will each use a different .ipsw file to install the iOS system software.

Looking at the name of an .ipsw file, we can learn all we need to know about its contents.  For example, an ipsw file called…

iPod4,1_6.1.2_10B146_Restore.ipsw

…is for a 4th Generation iPod Touch, as indicated by “iPod4,1”, which is known as the model identifier for this product. After the first underscore, we find the commonly used version number of the iOS software contained within – in this case, 6.1.2.  Next, we find the build number, or developers’ detailed version number – in this case, 10B146. After the final underscore, we see “Restore.ipsw” which is the common suffix for every .ipsw file.

iOS Deployment Models for OS X Deployments

As Apple continues to blend systems and features between OS X and iOS, lessons learned from iOS deployments are increasingly valuable to OS X deployments.  In Apple’s iOS 6 Education Deployment Guide, three deployment models are identified.  These models are adapted to OS X deployments below.

  • The Personal Ownership model  is described as “similar to the typical consumer experience. The education institution may or may not own the iOS device, but the end user takes responsibility for ongoing maintenance and retains ownership of all apps and content.”  This model is applicable to a great many OS X deployments.  I often define this as the user’s “functional ownership” of a computer even though the user may not have financial or legal ownership of the computer(s) in question.  Bring Your Own (BYO) programs clearly fall into this model, however it’s not uncommon to find organization-owned computers deployed in such a manner. If the end user has an administrator account, you may be dealing with a personal ownership model.
  • The Institutional Ownership model is what I have often described as a “traditional IT environment”.  Words and phrases such as “lock down” and “prevent” are prevalent here.  The user typically doesn’t have an administrator account and is often limited in how much they can deviate from the organization’s Standard Operating Environment (SOE, a useful term not very widely used in the USA, but prevalent elsewhere).  Given a clear, finite and realistic set of requirements based on the functions needed by the end users, this model can be used to great effect. The environments where this model works best are those with well-defined workflows. Creative users tend to be stifled in such an environment, and it takes a great deal of work and preparation on the part of an IT staff to ensure that systems deployed under this model are able to respond to changes in user need and advances in the technological ecosystem.
  • The Layered Ownership model blends the two models already discussed.  According to Apple, “The Layered Ownership deployment allows for both the end user and the institution to own their respective content on the same device, and the end user performs the majority of maintenance tasks on the device.”  This seems like the best of both worlds.  The organization protects its data and assets while freeing the user to work in whatever manner they find most efficient.  In this model, the user would have an administrator account, but the computer would receive some configuration and management from the organization’s IT staff.

Data

Proprietary and/or confidential data should be a primary concern of any IT organization.  iOS neatly sandboxes each application’s data making it easy to protect through managed apps, but this is not yet an option in OS X.  The growth of cloud systems, both public and private, may provide a solution.  Sensitive data can be accessed via secure websites and/or applications.  If the data is never resident on the client’s hardware, there’s nothing to leak.

Nomenclatural Consistency; RIP Imaging

This post is, in part, a response to Anthony Reimer’s well thought out article on deployment terminology, appearing at AFP548 on 21 May, 2013.

I do agree with a great many of Mr. Reimer’s points.  It is helpful to the profession at large, if we adopt some sensible terminology that is not only consistent, but aligned with Apple’s own lexicon.  After all, this is Apple’s world and we’re just living in it.  It surprises me how often Apple-focused technology professionals, at times even Apple-badged employees, display an ignorance of, or on rare occasions, contempt for Apple’s own established lexicon.

Some words in common use are archaic and should be culled from our collective vocabularies.  The entry for the word “machine” in the Apple Style Guide reads: “Don’t use when you mean computer” (italics Apple’s) and appears thirty times in Mr. Reimer’s article.  In the blue-collar mentality many of us have, “machine” brings about grand romantic illusions of a hardworking sweaty engineer in the bowels of an engine room.  The term also serves to portray the computer as a Victorian engine, whirring and clicking along as it solves a never-ending list of calculations.  This may be a lovely vision if you’re a fan of steampunk, but this vision is far from the reality of the solid-state computers and iOS devices with virtually no moving parts being deployed today.  I bring up this point not to nitpick, but to suggest consistency.  Apple has developed and published its own lexicon.  Why should we ignore that and invent our own terms?  I believe it is far more efficient to use Apple’s terminology whenever applicable and only invent new terms where there is an absence of terminology from Apple.

Another term you’re likely to hear, particularly from sales professionals, is “silos”. A common theme is to draw hard lines of distinction between organizations with terms such as “education”, “enterprise” and “government”.  Why create unnecessary divisive language?  Having worked in and for all of these types of organizations, I can attest that, at least for IT staff, they are purely artificial distinctions and serve only to satisfy the misconceptions and/or egos of the C-level or non-technical management staff.  Computers are computers regardless of whether the goals of the organization using them is to make cheese, cars, laws or to educate children.  Each organization is unique in the set of requirements it lays out for itself, with most organizations assembling their requirements without regard to whether an individual requirement is believed to be an education, enterprise or government item.

The bit of Mr. Reimer’s article that resonates with me the most is the term “customizing”.  I believe that imaging is dead and it’s successor is customizing.  With the prevalence of high-speed networks, Apple Recovery HDs, and advanced management tools such as The Casper Suite and its ilk, that there are few, if any, reasons to ever apply an image to a Mac.  One of the biggest challenges Mac system administrators have historically faced is that of creating a single operating system image or installer that will work on all of their hardware.  Many solutions have been put forth, most of them quite clever, but all sharing the fatal flaw that they are unsupported by Apple.  When you step outside supported models, you cause the proverbial buck to stop with you.  The last thing I suggest doing in any deployment scenario is to make yourself ultimately responsible for malfunctions.  The solution is at once easy and obvious.  Apple ships each computer with a functioning operating system.  Erasing and replacing that operating system is a waste of time.  Using deployment tools, the factory-installed operating system can be configured to meet the organization’s needs.  The only semi-valid argument I have heard against this approach comes from very security-conscious entities claiming that they can’t trust the installation that comes from Apple’s factory.  To these organizations, I ask: Will you be using Apple’s installer to replace the system you’ve erased; and if so, how is that any more secure than the original installation?

You may be thinking that this is all well and good for a new computer, but what about when a computer needs to be repurposed or reassigned?  This is where NetInstall, the Apple Recovery HD, or Internet Recovery if necessary, comes in.  Using Apple’s own installer, the disk can be erased and a fresh operating system, designed and tested by Apple for the hardware in question, can be installed.  Then it’s a matter of customization for the computer’s new intended use.