1. Lecture 2 “Structure of computer” Informatics

2. Computer is  general purpose device that can be programmed to carry out a set of arithmetic or logical operationsprogrammed  (Examples: cameras, phones)  Two main parts of computer:  Hardware refers to the physical parts of the computer  Example: piano is a harware  Software refers to the code that runs on the computer  Example: the music is the sofware

3. Computer Hardware There are 3 major parts that make up computer: CPU RAM Persistent Storage

4. CPU  CPU- Central Processing Unit  The brains  Performs simple operations e.g. Add two numbers

5. RAM  RAM- Random Access Memory  Temporary, working storage bytes  RAM is “volatile”, not “persistent”,… gone when power goes out Byte  Byte-unit of information storage  All measured in bytes, despite being very different hardware  1 byte is enough to hold 1 letter  Kilobyte, KB, about 1 thousand bytes  Megabyte, MB, about 1 million bytes  Gigabyte, GB, about 1 billion bytes

6. Persistent Storage: Hard Drive, Flash Drive HARD DRIVE  Stores bytes as a magnetic pattern on a spinning disk FLASH DRIVE  Stores bytes as electrons in a chip e.g. usb key, SD card in camera, flash chips built into a phone or tablet

7. Computer Software  Software –code that runs on the hardware  Software is machine code  CPU implements “machine code” instructions

8. Operating System  Operating system is set of supervisory programs, run when computer first starts  Starting/managing/ending other programs

9. Modern operating systems: functions ● Program execution ● Memory management ● Multitasking ● Disk access and file systems ● Networking ● Security

10. Operating Systems  There are three main families of operating systems:  Linux  Windows  MacOS

11. Linux Fedora, Ubuntu, RedHat, Suse mostly free mostly open-source (customizable)

12. Windows Most widespread operating system Windows 3.1, Windows 98, Windows ME, Windows XP, Windows Vista, Windows 7, Windows 8 Operating system is a property of Microsoft

13. MacOS bundled in Mac computers cannot work with other computers well-known for its’ pretty and intuitive user interface

14. Drivers  A device driver or software driver is a computer program allowing OS to interact with a hardware device