Software development

To understand software development, we start with its definition as given at the beginning of the corresponding Wikipedia page.

Definizione: Software Development

Software development is the process of conceiving, specifying, designing, programming, documenting, testing, and bug fixing involved in creating and maintaining applications, frameworks, or other software components. (Wikipedia EN)

Notice that this definition puts programming as only among many tasks involved in software development, indeed developers are much more than simple code writers.

Target Platform

Before starting developing a software, we need to know which platform we want to target. Such choice is made among a vast, always increasing list of hardware platforms.

Desktop and laptop PCs, possibly with different Operating Systems (Windows, Mac OS, Linux);
Mobile devices (smartphones, tablets, …), possibly with different Operating Systems (Android, iOS);
Large computing machines and/or infrastructure (Cluster servers, AWS, Azure, …)
Small embedded devices: Arduino, smartwatches, smartbands, …
Other smart devices: car, fridge, dishwasher, heater, …

In practice, it is impossible do develope once for every platform. The difference between them includes many aspects:

Screen size (if any screen is present at all);
Computing capabilities: CPU, memory, …
Libraries and framework available;
Hardware available (mouse, keyboard, GPS, antennas, …).

Esercizio

Consider these two devices you certainly own: a PC (either a laptop or a desktop) and a smartphone, list all differences in terms of:

screen
hardware
sensors
operating systems and libraries.

Native and Web

There are two broad categories of software development: native and web. Other distinctions can also be made, but we won’t discuss them here.

Definizione: Native Development

When the target platform is a specific operating system, we talk about native development. The term native refers to the fact that the tools used have been created specifically for the target platform.

An example of native development is the creation of a Windows application using .NET framework targeting an exe (executable) file. A typical native application is the web browser (Chrome, Firefox, …).

Definizione: Web Development

When the target platform are the virtual machines running inside a Web Browser, we talk about web development. The term Web refers to the usage of Web Browsers and to the fact that the results are (almost always) websites, rather then native programs.

An example of web development is the creation of a website using HTML/CSS and Javascript. We use web applications all the time, for example when accessing our GMail inbox or Spaggiari register through the browser.

Attenzione

Many web applications (e.g., GMail, Facebook, …) have a native App counterpart for the specific operating system (e.g., Android, iOS, Windows, …).

Pros and cons of Native and Web

It is interesting to compare native and web development to understand what are the the advantages and disadvantages of each of them.

Effort
- Native: High effort because we must address each supported platform
- Web: Low effort since the same code runs on browsers installed in different platforms
Efficiency
- Native: High efficiency because the code is run natively by the machine rather then virtualized
- Web: Low efficiency due to the virtualization which is slower than the machine
Security
- Native: Low security since the code may be executed with administrative privileges and gain access to all resources
- Web: High security because the code is generally run on a sandbox (a confined executing environment)
Cost
- Native: High costs because code must be developed for every target, sometimes it may require more code due to the usage of lower level languages (when compared with Web development)
- Web: Low costs because the code can be executed in different platforms and languages could be at higher level.
Expertise
- Native: High expertise are necessary because developers should know many platforms
- Web: High expertise are necessary because Web development frameworks are generally more complex
Reliability
- Native: Good reliability since the code is stored and runs in the target machine
- Web: Not reliability since the code is often on a different machine, thus inaccessible without an Internet connection.

Web Development

Today, we are witnessing a rapid shift towards web development. While desktop Apps are replaced by Web Apps, native development is mostly used in mobile platforms (Android and iOS). At the same time, cross-platform frameworks are becoming increasingly popular and widely adopted.

Definizione: Cross-platform

We call cross-platform tools and frameworks that target more platforms (typically more operating systems) at once. An example of a cross-platform technology is Java which is written once and run on many platforms (thanks to the Java Virtual Machine, JVM).

Web app architecture

The term architecture refers to the structure and organization of an application. It Web App this structure involves the frontend and the backend. Furthermore, elements like framework and server infrastructure are part of the architecture of a Web App.

Frontend development

The frontend is the part of a web app the users with, frontend development is the practice of designing and building user interfaces. This involves:

creating HTML, CSS, and JavaScript code that is visually appealing and
making the web page interactive, and responsive to user actions.

The Javascript code of the frontend, as well as the rendering of the web pages runs on a web browser, which is a software used to browse the Web. More precisely, all modern browsers implement a virtual machine that interprets Javascript code, such code is usually downloaded from the server and run on the client.

Backend development

The backend is the part of the web app that runs on the server and manages data, backend development is the practice of creating server-side applications. This involves:

writing code in server-side languages like PHP, Python, Java, Javascript, …
working with databases, APIs, and other backend technologies.

Full stack development

When we want to refer to both frontend and backend development, we talk about fullstack development. Nowadays, it is common to see job offers for all three type of development (as well as job offers for native development).

However, when the size of the development team grows (say beyond few units), it is common to see the team dividing into frontend and backend. In these cases, a developer specializes on one specific aspect, but it still needs to broadly know the principles and technologies of web development as a whole.