What is Pull Technology?

Mary Elizabeth

Some actions that happen between online material and a user can be initiated in one of two ways. Others are initiated in one way only. The initiation methods are referred to as push technology and pull technology. Push technology involves data being automatically delivered to the computer of the user, either on a schedule or based on some triggering event. Pull technology is the opposite: it involves a specific user request to move the data to the user’s computer. There are four frequent uses of pull technology: requesting mail, loading webpages, downloading from the Internet, and web syndication to a newsreader.

Looking up a patient's chart might be an example of pull technology.
Looking up a patient's chart might be an example of pull technology.

Email clients can work with either push technology or pull technology, but this depends on the client, rather than the user’s choice. If a client offering pull technology is being used, the client will be offered preference settings that will allow him or her to configure the email client to periodically poll the server and download the email. Once this step is taken, the downloading happens automatically, so this pull technology can feel like push technology. Nevertheless, the user maintains control and can change the polling interval, or even turn off the client, if desired.

Purchasing and downloading an ebook is an example of pull technology.
Purchasing and downloading an ebook is an example of pull technology.

On the Internet, every entry of a URL or click on a page link that results in a loaded webpage is the result of pull technology at work, although many people think of it primarily as “navigation.” It is clearer that something is being pulled when a user downloads some item from the Internet. This is the case whether when downloads a webpage to one’s printer, an ebook purchase from Amazon®, a new driver for one’s monitor, a photograph from Flickr®, a catalog of English Language Teaching titles from Oxford University Press Canada®, or webmail that one goes on line to retrieve oneself.

Web syndication allows users to gather updates from chosen websites and read them offline through a newsreader on their desktop, such as NetNewsWire®, if they choose. When they do this — rather than read them through a browser such as Bloglines®, which keeps them online — they are taking advantage of pull technology in a different way. The material of their choice will be delivered to them as it becomes available, but only because they made the request for it in the first place and only when they launch the program. Keep it off, and nothing is pulled.

Mary Elizabeth
Mary Elizabeth

Mary Elizabeth is passionate about reading, writing, and research, and has a penchant for correcting misinformation on the Internet. In addition to contributing articles to EasyTechJunkie about art, literature, and music, Mary Elizabeth is a teacher, composer, and author. She has a B.A. from the University of Chicago’s writing program and an M.A. from the University of Vermont, and she has written books, study guides, and teacher materials on language and literature, as well as music composition content for Sibelius Software.

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Discussion Comments

NathanG

@Mammmood - Frankly, I don’t know how user friendly the Internet would be if the majority of data transactions used the push versus the pull model.

Can you imagine navigating to a website and then having to tell the site, “Please send me all the text, images associated with this site, otherwise leave my browser page blank?” It wouldn’t be too practical.

There are push activities you can do however. Anytime you download stuff from a website you are pushing. Stuff doesn’t get downloaded to your computer automatically. If it does, it’s probably a virus.

Mammmood

@miriam98 - I think that my email client uses pull. I’ve set it up to match the settings provided by my ISP.

The moment that I launch the email client, the new server email gets downloaded. It’s automatic –I don’t have to ask for it. I suppose you could set up your client to ask for the email, but I don’t see any practical benefit to that.

miriam98

@MrMoody - I am a software developer and we work with push and pull concepts all the time. In our case, we use it with reporting.

If I develop a report and connect it to the database, usually the database will automatically send data to the report the moment that the report is loaded. This is the pull approach.

However, sometimes I don’t want data automatically sent. I may want to filter it somehow. So what I do then is I write code to go to the database, apply a filter, and then send data to the report.

This is the push approach. It doesn’t happy automatically; it involves my code doing some gymnastics first and then pushing the data. If the code doesn’t do its thing, no data gets displayed.

MrMoody

When I first began using the Internet years ago, I didn’t immediately understand the concept of website navigation. Whenever the URL of my browser changed to go to a particular site, in my mind I accepted as reality the metaphor that I was “navigating to” that site. I wasn’t quite sure how it worked, but that’s what I thought.

Then one day I looked at my browser’s settings and noticed that it had a folder where it said it kept temporary files. When I looked at that folder, I saw images files from sites I had “browsed” to! The files were local on my machine.

Gradually it dawned on me that the act of navigating was in fact a process of pulling files from a server onto my local machine. It was the browser that did the real magic of displaying it for me in a way that I could understand.

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