CS1020:   Introduction to Computers

Instructor Outline Syllabus Projects Links

Files

File

• a named collection of data.
• The most common unit that a computer user uses to store data.
• Ultimately stored as a long string of zeros and ones.
• Different kinds use different ways of encoding data.
• Size is measures in bytes. (Byte is 8 bits)
• Naming convention:
  
  • filename.extention
• extention - typically indicates the kind of data format. There are many kinds of data formats out there ...here are a few.

  doc = MS Word Document
  ppt = Powerpoint
  txt = text file
  xls = Excel spreadsheet
  jpg = JPEG image
  pdf = Acrobat file
  htm or html = HTML file

ASCII or Binary

• All files are either ASCII or Binary
• ASCII files have the data represented as alpha-numeric characters and are readable when opened with a text editor (like notepad on Windows machines). Examples of ASCII files are .txt, .html or .htm, .xml, most source code for computer programs.
• Binary files are considered un-readable. They are data represented with 1's and 0's. When you open them up with a text editor it looks like "garbage". The following illustrates the contents of a GIF image called Projects.gif. Most data formats are binary including most images, video, sound, office processing formats (word, ppt, excel, etc.).