Acsm, ePub, mobi, PDF, what are the formats of e-books

Not all ebooks are the same. We are not referring to the genre or the title of electronic books, but to the formats, that is to say the extension with which they are published

Although some readers would never give up the smell of printed paper, e-books represent a valid and above all convenient alternative. They don't weigh much, except for a few kilobytes, are easily transportable - even a microSD card is sufficient - and are not subject to wear and tear.

But what are e-books? They are electronic books, that is, texts that are not sent to print, but remain simple digital files. They are accessible from multiple devices. You can, for example, get carried away by the words written in an e-book on a smartphone - although in the long run the small screen can tire your eyes - on a computer or tablet. And not only that. Often the word e-book is associated with e-readers, tools created specifically to read electronic books. Compared to other devices, some e-readers are e-ink, a technology that partly cushions the effects of the display.

Not all ebooks are the same. We are not referring to the genre or title of ebooks, but to the formats, that is, the type of files with which digital texts are made and disseminated. An e-book can have one of these three extensions: epub, mobi and PDF. Don't you know what an extension is? It is the final part of the file name. Let's take an example: book.epub. This is an e-book in epub format.


In between the three extensions there is another one: the ACSM file. Actually, it is not an e-book format. Let's try to understand what it's for. Some e-books are protected by Adobe DRM, a system that serves to prevent the illegal dissemination of a copyrighted text. In order to download these texts, the user first receives an .ascm file with which he then completes the download. Having said that, let's move on to talk about the three formats.


This is one of the most used formats for publishing books. It is an open format and is based on the XML programming language. The main advantage of the ePub format is that it optimizes the text of the book. In other words, thanks to this file type, the ebook automatically adapts to any electronic device. It is understood that the ePub format does not require a specific device to be read. However, it is always necessary to download a specific program or app to enjoy a content developed in ePub.


Let's move on to mobi. If you have a Kindle, the e-reader produced by Amazon, you will surely be familiar with this format. Also because it is not possible to read e-books in other formats on the device developed by the e-commerce giant. In fact, all e-texts available for Kindle are in mobi format. Unlike the previous one, mobi is a proprietary format.


And let's close with the most common and well-known format in the world: PDF. Acronym for Portable Document Format, it is a format from Adobe and allows anyone to open a file, regardless of the device or program used. Some e-books are also published in this standard and it is preferable to read them mainly on computers, tablets and smartphones, while on e-readers there may be some formatting problems.