Crossword operating system

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Across
  1. 2. Referred to as "big iron"
  2. 3. Operating systems by cellphones
  3. 5. Bill Gates was a founder of this company
  4. 7. Software for virtualization
Down
  1. 1. computer with a microprocessor and a central processing unit (CPU)
  2. 4. Operating systems developed by Apple
  3. 6. Popular version of UNIX operating System
  4. 8. Is the smallest unit of data in a computer