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Basic concepts
IT
Information technology  represents study, design, development, support and use of computers and computer based systems, particularly hardware and software. ((ITAA), 2009)
ICT
Represents IT together with digital communication technologies.
Hardware
Represents objects which you can touch (parts of a computer)
Software
Represents intouchable (intačebl), programs and data.
Software and Hardware are closely linked to each other. Software is stored on hardware, you buy new software recorded on a piece of hardware.
Computer
A lot of definitions exists.
Computer is a programmable machine which can:
-          Process different sets of data
-          Store and execute programs
-          Communicate with the user
What is a computer program? It is a sequence of instructions?
How does computer work?
Computer endlessly repeats the same set of operations. Processor processes one instruction of a program (from the memory), or from the user (from an input device) after another. It decodes and executes each instruction. The processor works with so called machine code (mašín koud – strojový kód), which is computer language – based on two digits. All instructions are “translated” (compilated) into computer language by compilers.
Try to write sequence of instruction for:
-          Sign the paper
-          Turn off TV
 
Binary system
Computer works with instructions and data which are in computer language based on two digits 0 and 1 – in binary system.
Conversion between number systems:
Binary                  Decimal                      Hexadecimal
0                          0                                             0
1                          1                                             1
10                        2                                             2
1010                   10                                           A
1100                   12                                           C
1110                   14                                           E
1111                   15                                           F