An iPhone is a combination of hardware and software components structured together to work as a small computer. Systems thinking offers an approach to make sense of this combination by focusing on its modular design. In developing the smartphone, as with other media technologies, engineers and designers had to structure its different components as a system of subsystems that could inter-relate to work together as necessary. An iPhone, then, is modular in the sense that it is made up of modules, “unit[s] whose structural elements are powerfully connected among themselves and relatively weakly connected to elements in other units” (Baldwin and Clark, 2000, p. 63), and figuring out what those modules are and how they relate to one another can shed lights into some of its features.
The structure of an iPhone is designed so that hardware and software interact, and so the user interacts with the phone mostly through software. Both hardware and software are structured modularly, which can be explored by going through the steps a user would go through to post an Instagram video.
To post a video on Instagram, I need to first turn on my phone and access the app. For this to happen, an operating system (OS) must be in place to manage how the software and hardware will interact, and this is a first module I encounter as I press the iPhone’s round button, which sends a signal to the OS and turns it on, gives me the option to enter my passcode, and shows me the home screen where I find the app’s widget. The software of the phone is first structured as an operating system that “manages computer hardware and software resources”  and thus allows applications to run on the phone.The OS in the iPhone is in itself a module of software, one that is designed by Apple and called iOS.
A characteristic of modules is that, while they serve a purpose in themselves, they can also interconnect with other modules to serve other purposes as needed and as wanted. To be able to do so, they have interfaces (specifications of how to interact with such module). The specifications to interact with iOS are visible only to an extent. Because it is an OS designed by Apple, it is meant to work only with its hardware and is thus closed source. Users can develop applications to run on it by following specifications set by Apple and share or sell them through the Apple Store.
After opening the app, I select the photo icon on the bottom menu, which turns on my camera, select the video option on the sliding menu, which changes the camera mode and turns on my microphone, and film for a specific amount of time. In going through these actions, I am interacting with an array of modules designed by Instagram engineers and designers with the iPhone in mind. Instagram is a social network site that allows users to share one photo at a time with their followers. In itself, Instagram is a module among the universe of social network sites out there, which has figured out that photo-sharing is a key activity for users and designed an app around that concept. As an app, it is software that allows me to take several actions, each one of which can be described as a module in itself. For example, if I view my streamline before posting anything, I interact with a function that connects to the Internet to get data and displays that data to me as snippets in which I see a photo, information on the user who shared it and comments.
To post a video, I interact with a module of functions that connect the app to the camera and microphone and display options for me to capture video, edit it in specific ways, write a description, post it on Instagram and then share it on other sites. The various modules in the iPhone are interacting while I take these actions even though not all of them were designed by the same people and only do so as needed. When I go through my stream, the app does not need to interact with the phone’s camera and microphone, but it does so swiftly when I turn on that option, since the app was designed for the iOS and thus has access to them. All the while, however, it needs to connect to the Internet, for which it relies on the phone’s hardware. For each of these components to work together, they have interfaces that allow them to interact in specified ways, as well as a user interface through which I interact with it.
An iPhone, then, can be described as an interface of interfaces, each of which allow us to interact with specific modules of software that interact with each other through an OS that allows different functions to use the different features of the phone as needed. At the same time, this modular design is structured in a way that lets its modules be open only as wanted. The example of the OS shows that Apple can open some of its interfaces and thus promote innovation, as Lidwell, Holden and Butler explain it can (2003, p. 136), but it can do so through specific regulations, thus curbing the levels of innovation that can be reached.
Carliss Y. Baldwin and Kim B. Clark, Design Rules, Vol. 1: The Power of Modularity. Cambridge, MA: The MIT Press, 2000.
Lidwell, William, Kritina Holden, and Jill Butler. Universal Principles of Design. Revised. Beverly, MA: Rockport Publishers, 2010.
 Operating system: https://en.wikipedia.org/wiki/Operating_system