Recently a new iPad user asked me how she could get a photo from her computer into her iPad. I could have simply answered that it could be done with iTunes or I could have recommended any one of several iOS apps that would do the job and she could have figured the rest out for herself. On the other hand a more general knowledge of how files are transferred from one computer device to another would be helpful in making choices between applications and understanding how to use them. In this post I will review the basic concepts of file sharing and transfer between computers.
To accomplish a file transfer one of the computers is assigned the role of a server and the other the role of a client. Each computer will have appropriate server or client software installed. A file transfer from the server to the client is called a download, A transfer from the client to the server is an upload. Generally, files intended to be shared are stored or “hosted” on the server. In this way many devices can be clients to a single server.
The rules and associated syntax that actually accomplish the transfer is called the protocol. In the “early” days before the Internet, the most popular file sharing protocol was FTP (File Transfer Protocol). FTP is still in use today although its usage is declining in favor of more modern and more secure protocols including WebDAV, SSH, and others. To access an FTP server on another computer your device must an FTP client. There are many to choose from and some are both free and cross platform. Examples are Filezilla and Cyberduck. When the Internet was invented it needed a new protocol to share web pages. Web pages are written in HTML (Hypertext Markup Language) and the associated protocol is HTTP (Hypertext transfer Protocol).
Today a web browser, that is, a client for HTTP, comes pre-installed on every computer sold going by such names as Internet Explorer and Safari. iI you don’t happen to like the one provided there are a number to choose from including Firefox, Chrome and Opera. Now wouldn’t it be nice if your favorite web browser could double as a file transfer client? Well that is exactly what a webserver application does! With a webserver app installed and running on your iOS or Android device you enter a URL into the browser’s address field that looks something like this:
where xxx will be a number assigned to the device by your router. Don’t panic, the software figures this all out for you and you simply copy the URL into the browser. Typically, a “drag and drop” interface will appear on your desktop screen. You drop the photo (or other file) onto the interface and it is sent to your mobile device. Two apps that I would reccomend for iOS users are the Photo Transfer App and Air Transfer Pro. Android users should consider WiFi File Transfer Pro. These apps may cost a dollar or two but they are worth every penny.
Another approach is to use a remote server, often referred to as a cloud server. Dropbox is very popular and offers 2 GB of remote storage for FREE which is more than enough for most purposes. Other similar services include box.net, Microsoft SkyDrive, Ubunto One, and others. Dropbox was an early to offer this type of service which partly accounts for its popularity. As such it is integrated into many apps thereby simplifying it’s usage. To use a cloud server the user establishes an account and acquires a username and password. Often the username is simply an email address. A free client is installed on both the desktop and mobile devices. Some of the services, including Dropbox, also offer a web interface making the client optional. The user then uploads the photo (or other) file to be transferred from the desktop machine to the remote server. Then the file is downloaded to the mobile device by using the client installed there and (sometimes) performing a “sync” operation. Obviously the use of a cloud server requires an Internet connection and one might not always be available. However, files uploaded to the users “public” area are assigned a public URL accessible by anyone, anywhere. It is undoubtedly the easiest way to share a file with friends.
A client – server relationship will always exist when files are transferred between computers. The methods in which it will be implemented will differ. the “best” method will depend upon individual situations. Having a selection of software tools available and a knowledge of how they work will enable you to make good choices.