Revision notes

Revision notes

1. Data storage capacity

   • Data storage capacity is the measurement of how much data can be stored in a storage device.
   • 1 byte = 8 bits
   • Each bit is represented by either a 1 or a 0 (on or off)
   • 1 byte can hold 1 character of data

2. Data compression

   • Lossless compression
     • Lossless compression reduces the size of a file without any damage to the file or reduction in quality.
   • Lossy compression
     • To get low file sizes, lossy compression permanently removes data from the file that the computer believes you can do without

3. Von Neumann

   • Von Neumann architecture is based on the stored-program computer concept, where instruction data and program data are stored in the same memory. This design is still used in most computers produced today.

4. Programming data types

   • In programming, data types are the attributes that specify the type of data that an object can hold. We need to declare a data type for variables and arrays.

5. Web browser

   • A web browser is a software program which allows the user to retrieve and display web pages (and other resources) from the world wide web.
   • Web browsers interpret the HTML code from websites and present it to the user in a format we can understand.