Computer Science 1026A/B Chapter Notes - Chapter 1: Hard Disk Drive, Microsoft Word, Auxiliary Memory
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29 Dec 2017
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Computer Science Fundamentals I Lecture Notes - CS1026
Chapter 1
Comp Programs
- tells comp the sequence of steps needed to complete a specific task
o program consists of a very large number of primitive (simple) instructions
- Programming: Act of designing, implementing, and testing computer programs
Hardware & Software
- Hardware: Physical elements in a comp system (e.g. monitor, mouse, external storage,
keyboard)
- Central Processing Unit (CPU): performs program control & data processing
- Storage Devices: Memory (RAM) & secondary storage (hard disk, flash drives, CD/DVD
drives)
- Input/output devices allow user to interact w/ comp (mouse, keyboard, printer, screen…)
- Software: the programs the computer executes
o An application program (e.g. Microsoft Word, comp games, operating systems &
device drivers)
o Sequence of instructions implemented in some language & translated to a form
that can be executed or run on the comp
- Comps execute basic instructions in rapid successions
o Basic instructions can be grouped together to perform complex tasks
o Comp transmits info (output) to user through display screen
o User can enter info (input) for comp using a keyboard/mouse
- Comps can be self-contained units or interconnected through networks
- CPU consists of the control unit (directs operation of processor: controls communication
& coordination between devices, reads & interprets instructions, determines sequence for
processing the data, provides timing & control signals) & the arithmetic logic unit
(contains the circuitry to perform calculations & do comparisons: does exactly what
control unit tells it to do)
- Primary storage is composed of memory chips: electronic circuits that store data using
electric power
- Secondary storage: slower, less expensive persistent storage without using electric power
(hard disk)
- Data & program located in secondary storage & loaded into memory when program is
executed
- Memory: typical comp has main memory from 4 GB to 32 GB (1 byte=8 bits, 1
kilobyte=1024 bytes, 1 megabyte=1 million bytes, 1 gigabyte=1 billion bytes)
- Executing a program:
o Program instructions & data (text, numbers, audio, video) stored in digital format
o When program starts, brought into memory where CPU reads it
o CPU runs program one instruction at a time (program may react to user input)
o CPU reads data (incl. user input), modifies it, writes it back to memory, screen, or
secondary storage
Algorithms
- Write algorithms to get comp to perform a task
- Sequence (order matters) of actions to take to accomplish the given task
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