Lecture 2
“Structure of
computer”
Informatics
 general purpose device that
can be programmed to carry
out a set of arithmetic or
logical operations
 (Examples: cameras,
phones)
 Two main parts of computer:
Computer is
 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
Computer
Hardware
There are 3 major parts that make
up computer:
CPU
RAM
Persistent Storage
 CPU- Central Processing Unit
CPU
 The brains
 Performs simple operations
e.g. Add two numbers
RAM
Byte
 Byte-unit of information storage
RAM
 RAM- Random Access
Memory
 Temporary, working storage
bytes
 RAM is “volatile”, not
“persistent”,… gone when
power goes out
 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
HARD DRIVE
Persistent
Storage: Hard
Drive, Flash
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
 Software –code that runs on the hardware
Computer
Software
 Software is machine code
 CPU implements “machine code” instructions
Operating
System
 Operating system is set of
supervisory programs, run
when computer first starts
 Starting/managing/ending
other programs
Modern
operating
systems:
functions
●
Program execution
●
Memory management
●
Multitasking
●
Disk access and file systems
●
Networking
●
Security
Operating
Systems
 There are three main families
of operating systems:
 Linux
 Windows
 MacOS
Linux
•
Fedora, Ubuntu, RedHat,
Suse
•
mostly free
•
mostly open-source
(customizable)
•
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
Windows
MacOS
•
bundled in Mac computers
•
cannot work with other
computers
•
well-known for its’ pretty
and intuitive user interface
Drivers
 A device driver or software
driver is a computer program
allowing OS to interact with a
hardware device