internal parts of computer and their What's in a computer?

internal parts of computer and their What's in a computer?

A basic computer has at least 8 basic components which include a computer case or tower, motherboard, Central Processing Unit (CPU), Power Supply Unit (PSU), Random Access Memory (RAM), hard drive (HDD), Graphic Processing Unit (GPU) and some type of optical drive which would be your CD/DVD drive.

  • Logical or functional organization : "architecture"

  1. What the pieces are, what they do, how they work 
  2. how they are connected, how they work together
  3. what theis properties are

  • Physical structure

  1. what they look like, how they are made

  • Major pieces

  1. procssor ("central processing unit" or Cpu) does the work, controls the rest
  2. memory (ram - random access memory) stores instructions and data while computer is running

  3. disks ("secondary storage") Stores everything even when computer is turned off
  4. other devices (peripherals")

Block diagram of typical laptop/desktop

internal parts of computer and their functions
internal parts of computer and their functions


  • can perform a small set of basic operations ("instructions")

  1. arithmetic: add subtract, multiply, divide ...

  2. memory access: Fatch information from memory , store results back into memory
  3. decision making: compare numbers , letter , ...

  • Decide what to do next depending on result of previous computations

  1. control the rest of the machine Tell memory to send data to display; tell disk to read data from network

how fast is fast?

  • Cpu uses an internal "clock" (like a heartbeat) to step through instructions

  • 900 mhs , 2.4 ghz, etc . Is the number of clock ticks per second

  1. 1 herz = 1 tick per second; abbreviated 1 hz
  2. mega = million
  3. giga = billion
  4. 1 mhz = 1 megahertz = 1 million ticks per second
  5. 1 ghz = gigahertz = 1 billion ticks per second = 1000 mhz

  • One instruction (like adding two numbers) might take one, two or several ticks, depending on design of the cpu

  1. might even complete more than one tick

  • Very rough approximation: pc/mac processors execute about 2 billion instructions /sec

memory (random access memory = "ram")

  • A place to store information while the comter is running

  1. the pragrams that are running the operating system (windows, mac os, unix/linux,...)

  • Valatile: forgets everything when power is turned off

  • Limited (though large) capacity

  • Logically, a set of numbered boxes ("pigeonholes"? Mailboxes?)

  1. each capable of storing one byte = 8 bits of information a small number or  a single character like a or part of a larger value

  2. random access cpu can access any location as any other location
0 1 2 - 16

what's a bit? What's a byte?

  • A bit is the smallest unit of information

  • Rapresents one 2 way decision or a choice out of two possibilities

  1. yes/on, true/ false, on/off, m/f, ...

  • Abstraction of all of these is represented as 0 or 1

  1. enough to tell which of two possibilities has been chosen
  2. a single digit with one of two value
  3. hence "binary digit"
  4. hence bit

  • Binary is used in computers because it's easy to make fast reliable, small devices that  have only two states

  1. high voltage/low voltage, current flowing/not flowing (chips)
  2. eletrical change present/not present (flsh)
  3. magnetized this way or that (disks)
  4. light bounces off/doesn't boesn off (cd-rom, DVD

  • All information in a computer is stored and processed as bits

  • A byte is bits that are treated as a unit


internal parts of computer and their functions

  • A place to store information when the power is turned off

  • Usually based on magnetic surfaces, rototing machinery

  • Logical/funtional structure: folders (directories) and files

  1. your information papers, mail, music, web page, etc
  2. programs and their data: firefox, word, itues, etc
  3. operating system (s): windows, macos, unix, linux, palmos, etc
  4. bookkeeping info: where things are physically

other views of a disk: windows, unix

internal parts of computer and their functions

other things

  • Cd-rom, cd-r, cd-rw: dvd

  1. read only, recordable, rewritable, ~650 mb capacity same format as audio cd but spins much faster
  2. DVD typically 4.7 or 8.4 GB

  • Modem

  1. converts info to/from sound for sending by telephone
  2. 56 kilobits per second (56 kbps): ~5000 characters/second

  • Network interface

  1. connects computer to network, usually ethernet (as in dormnet)
  2. ethernet transfers data at 10~1000 megabits per second (10 mbps ~ 1 MB/sec)

  3. wireless is compatible with ethernet ("wireless ethernet") 802.11g (11 Mbps), 801.11g(55 Mbps), 802.11n(600 Mbps), etc

  4. dsl and cable modems are ethernet compatible slower than ethernet (typically 0.5 ~ 4 Mbps) usually at home

  5. fiber (e.g verizon fios) might be 10 Mbps down, 2 Mbps up

  • Gadgets ("peripherals") on the bus, especially USB

USB 2.0 is 480 Mbps etc

Functional designis not physical implementation

internal parts of computer and their functions

  • Block diagram is "architectural" or "functional" or "logical" design

  1. gives components, shows how they are connected, maybe what they do

  • Physical construction is how it's built

  1. usually many different ways to build same functional or or logical design
  2. will all behave more or less the same (same functions)

  • Important general rule: the logical/functional organization does not describe a physical implementation

  1. logical abstracts away irrelevant physical details

2020 freshman offering:

internal parts of computer and their functions


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