MTA 98-364 Theory: Data Transfer

Data transfer files have standards so they can be transferred to any computer, hardware or application. Graphics, text, sound or numbers don’t need to be transferred on physical media anymore.

Data file types

Data files are stored in a number of formats, the formats depend on which application created the file to begin with. For example, Microsoft Word stores files as *.doc but Adobe Photoshop stores files in a different format - *.psd. The file extension identifies the file's format.

Opening files of different formats

When data is transferred from one computer to another, the computer receiving the data file may not be able to read the format without the right application installed. For example, an image created in Adobe Photoshop and saved as a *.psd file (Photoshop's format) would not be readable by Microsoft Paint.

This is becoming less of a problem as standardisation matures and applications expand the list of file types they're able to read.

Translating between file types

Data can be stored temporarily in a computer's RAM as a means of transfer from one application to another. In Microsoftoperating systems this feature is called the clipboard and it can copydata from one application and paste it into another. Nearly all other operating systems support this functionality.

For example you can create a graph using a spreadsheet application and then use the clipboard to copy the graph to a desktop publishingapplication.

Limitations

1. Certain elements of one document may not be copiable to another application, eg video.
2. Some file features (eg text layout and formatting) may be lost in the translation to a different format.

Import and export

Most applications have the ability to import and export data. Export saves the file in a format that's readable by other applications. Import opens a file created in another application for viewing or editing.

Standard file types

The need to import and export data files has led to the development of several standard file types that many applications can understand. Examples are jpg and gif files for images, and mp3 files for sound; but there are also standard file types for text, movies, and spreadsheetdata.

Often an application of a different type can import data, for example, aword processor may be able to import a spreadsheet file.

XML files

Recently program developers have started to use the XMLweb page file format as the standard way to store data, for example, the new Microsoft Office suite makes use of XML. RSS feeds on the internetalso make use of this format. Such files can be read by any browseron any computer, making it very easy to transfer data between computers.

Other examples

Other standard file types, such as zip and pdf, have been developed as ways of distributing data in the most efficient way possible. They do this by compressing it using zip technology or making it possible to read using a freely available downloaded reader application, as is the case with PDF files.

Rapid transfer of data

Files can be easily transferred and shared across the globe using theinternet. A file could be:

• emailed as an attachment
• sent over instant messenger
• downloaded from a website/web server
• accessed over a private network

Documents, eg a spreadsheet, can be stored on a web server and then accessed via any computer with an internet connection and aweb browser. Collaborative working is possible too, where multiple people contribute to the same document.

This makes the world very small as far as transfer of data is concerned. It has allowed many companies to outsource some or all of their operations. This is where companies transfer activities such as ticket processing for airlines or telephone banking queries to workers in a country where wages and running costs are relatively low. Often the time difference between the two countries gives even greater convenience.