DevOps: Installing macOS 13.0 Ventura and downloading/installing older available macOS versions

Apple likes to publish a new Mac operating system every year, including beta versions and incremental builds, and there can sometimes be many of those released throughout the year, like we’ve seen in 2022. On October 24 of this year, Apple graced us with macOS Ventura 13.0. Last year, 2021, the company gave us macOS 12.0 Monterey. Wouldn’t it be nice if you could just get a list of available macOS versions, select the one you want, have that macOS installer app download to your /Applications folder, and then you can run that installer whenever you’re ready? You can and I’ll show you how. Here’s what you see after you download the installer for macOS 13.0 Ventura (installer highlighted in green):

More specifically, I’ll tell you how to install Apple’s new and first alpha version of its desktop operating system software, macOS Ventura 13.0, from a Mac that is most likely still on macOS Monterey — especially if you keep up with the Apple world. I’ll also tell you how to download installers for approximately every public macOS build number within the last two years.

In today’s tutorial, we’ll be using the dreaded command line, but don’t worry. All that pretty user interface can just make code more buggy, and Apple always seems to have problems with getting new macOS versions downloaded and/or installed. Today, we’ll be cutting out some fluff and talking (almost) directly to macOS using a Terminal command called softwareupdate. It’s very reliable. I know everything I show you here today works on Monterey and Ventura and I know the command goes all the way back to macOS El Capitan 10.11. If you’re using softwareupdate on an older macOS version, just do a man softwareupdate at the command line and study the help. Here we go…

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The real importance of WWDC 2021: raw computing power (CPU), raw graphics power (GPU), and big high resolution screens

Photographers can’t professionally fine-tune an image of a mountainous landscape’s foreground and background on a tiny little iPhone screen. A data scientist can’t layout graphs, matrices, vectors, and spreadsheets on a tiny little iPhone screen. A customer service representative can’t troubleshoot a technology problem without searching through several device schematics, handle several different calls at once, be on the phone with one customer, be texting with another customer, and looking at a user’s guide that shows which buttons and switches do what things on a tiny little phone screen. Can you imagine trying to design, read, write, and debug code, and layout your UI with Xcode on an iPhone? (I could on a large iPad or MacBook, but not a phone).

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Controlling chaos: Why you should care about adding error checking to your iOS apps

NOTE: The second installment of this article, “Controlling chaos: Error Handling in Swift 4 with do, try, catch, defer, throw, throws, Error, and NSError,”, has just been released.

In this tutorial, the first in a series of tutorials, we’re going to discuss the arduous topic of looking for unexpected values, events, and conditions that arise during program execution, using a technique I like to call “error checking.” Today, I’ll concentrate on the reasons why you should check for errors. I’ll mention a number of techniques I use but leave detailed discussion of those techniques and sample code to subsequent articles. The purpose of this tutorial is to convince you to make use of error checking in your apps. You ignore errors at your own dire peril. This is sink or swim. If you put out a crappy app, no one’s going to use it because you’ll get a bad reputation at Internet speed, and employers/customers will be more than happy to leave you behind forever for other app developers who aren’t too lazy to write quality code.

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Protocol Oriented Programming in Swift: Advanced Applications

The original article – Protocol Oriented Programming in Swift: Is it better than Object Oriented Programming? – was published on


We’re going to talk in-depth about protocol-oriented programming (POP) using Swift 4 in this article. This post is the second and final article in a two part series. If you haven’t read the first, introductory article, please do so before continuing onwards. Today, we’ll: discuss why Swift is considered a “protocol-oriented” language, compare POP and object-oriented programming (OOP), compare value semantics and reference semantics, consider local reasoning, implement delegation with protocols, use protocols as types, use protocol polymorphism, review my real-world POP Swift code, and finally, discuss why I’ve not bought 100% into POP. Download the source code from the article so you can follow along: There are 2 playgrounds and one project on GitHub, both in Xcode 9 format and written in Swift 4.

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Downloading and installing an old version of OS X (mac OS) on your Mac

We’re going to talk about installing a version of your Mac’s operating system (OS), known as “macOS” or “OS X,” on your Mac, older than the one you’re currently running, on a partition of your primary hard drive or on an external hard drive. You may find that your current instance of OS X is too unstable for normal day-to-day usage or more heavy-duty tasks like development. Remember all the problems people had when they upgraded to OS X 10.13, also known as “High Sierra?” Oy, vey. You might have been like “Get me the heck outta Dodge!” You wanted or needed to get back to a stable OS, like Sierra (OS X 10.12) or El Capitan (OS X 10.11). For developers, you may have to install an older version of Xcode not supported by your latest OS. For Cocoa/macOS developers, you may need to make absolutely sure that your desktop apps are backward compatible, and the only way to do that for sure is to install and run your apps on older versions of macOS. I will show you, step by step, how to get a valid copy of an older version of macOS, make a bootable installer disk, and install the old OS.

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Polymorphism in Swift 3: manipulate multiple related controls with one IBOutlet and one IBAction

How would you enable or disable multiple user interface controls using one IBOutlet and one IBAction? For example, you might need to disable a UITextBox and UISegmentedControl because a user’s login has expired. Perhaps a user hasn’t filled in some required fields on a form, so you want to disable several buttons. Watch the following video to see how I built a Swift 3 app to use a UISwitch to enable or disable four controls all at one time — and I demonstrated the object-oriented programming (OOP) principle of polymorphism:

Refresh your memory about OOP and inheritance.

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My latest iOS app, AirStitch, accepted into App Store today

My latest iOS app, AirStitch, was accepted into Apple’s App Store today. I developed the app in Objective-C, targeting the iOS 9 SDK, using Xcode, following the requirements provided by BriTon Leap, Inc. The company is the world’s leading developer of custom embroidery design software. Download the app for free and enjoy. The app is a marvel of engineering.

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Concurrency in iOS: serial and concurrent queues in Grand Central Dispatch (GCD) with Swift 3

[Download the full Swift Xcode project from GitHub.]
[Download the full Objective-C Xcode project from GitHub.]

UPDATE: I’ve updated this article for Swift 4, learned a few new tricks, and taken advantage of the Swift 4 compiler’s “intelligence.” Please check out the new version as it’s more comprehensive and detailed, and my source code has been highlighted and commented to better help you understand the sometimes confusing concept of parallelism. There’s a brand new Xcode companion project, too.

Today, I’m going to start answering some of the concurrency questions I asked you to ponder in yesterday’s post entitled “Concurrency in iOS — Grand Central Dispatch (GCD) with Swift 3.” Specifically, I’m going to write some code in Swift 3 and Objective-C showing you the difference between serial and concurrent queues. But before coding we’ll talk about concurrency in general, the terminology used in discussing concurrency (threads, process, and tasks), the differences between the terms “concurrent” and “parallel,” the differences between serial and concurrent queues, the differences between synchronous and asynchronous methods/functions, and finally we’ll wrap up with some more definitions you need to know about.

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2016: A good year to be an iOS app developer (and how to become a better one)

It can be good to be an iOS app developer, but not easy to be a great one (we’ll talk about that later in this article). There are many opportunities for app programmers looking to work as employees for companies. There are plenty of opportunities for developers who prefer freelancing. It’s frustrating, trying to come up with novel apps that generate any significant revenue, when it seems that every idea under the sun has already been turned into an app by “someone else.” Apple continues to push out buggy versions of iOS, the iOS SDK, and Xcode — especially in early versions of new products. Yet most of us would agree that Apple’s hardware and software, even their development tools, continue to be elegant and cutting edge. It’s hard to argue with the bottom line as “Apple App Store developers raked in $20 billion in 2016, up 40% year over year,” according to an article from CNBC:

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