Review of Classes 13

1
Review of Classes 1-3

• Let's pack 6 hours of lecture and 400-some slides
  into one short presentation!

2
History

• Before 1981
• Lots of little manufacturers
• 1981-1987
• IBM develops the PC, runs the market
• After 1987
• IBM looses market share
• Intel (chips) and Microsoft (programs) mostly run
  the market

3
Computer numbers

• Computers represent everything as numbers
• A number is made of bits
• Each bit can be a 1 or a 0
• This is binary, or base 2
• There are 8 bits in a byte
• 1,024 bytes in one kilobyte
• 1,048,576 bytes in one megabyte
• 1,073,741,824 bytes in one gigabyte

4
More numbers

• Humans write binary numbers in hex to make them
  shorter and easier to use.
• Hex is also called base 16
• Pictures, sounds, and documents are all
  represented in the computer as numbers made out
  of bits.

5
Chipsets

• Usually two chips
• Northbridge or Graphic and Memory Control Hub
  (GMCH)
• Connects CPU to Memory and Video card
• Very fast, moves lots of data
• Southbridge or I/O Control Hub
• Connects CPU and Everything that isn't Memory or
  the Video card
• Drives, sound codecs, expansion slots

6
Devices

• Input
• Camera, mouse, scanner, keyboard
• Output
• Monitor, speakers
• Processing and storage
• CPU, hard drive, memory
• Some combination of those three
• Network card, CD burner

7
Bus

• A set of wires that allow devices to transmit
  data
• USB
• Connects computer to external devices.
• Frontside bus
• Connects CPU and Northbridge
• Parallel port
• Connects computer and older printers

8
Serial and parallel

• Serial transmits each bit one after the next
• Requires fewer wires, so cable is thinner
• Generally slower, but see below.
• Parallel transmits all the bits of one byte at
  the same time
• Requires more wires
• Generally faster, but modern serial buses can
  beat older parallel buses.

9
Power

• Motherboard uses 20 or 24-pin connector
• May have extra connectors for more power
• Floppy uses Berg or mini connector
• Old hard drive uses Molex connector
• So do CD-ROM drives
• New hard drive uses SATA power connector

10
CPU

• PCs use Intel CPUs
• Macs used PowerPC and 68K CPUs, now they use
  Intel CPUs too
• Different families of CPU have different
  instruction sets
• Like a language for a CPU
• Tells the CPU where to get data and what to do
  with it

11
Development of CPUs

• Started out simple, with single core and no cache
  RAM
• Later designs added L1 and then L2 Cache
• Pentium Pro, other Pentiums
• Later designs added more cores
• Pentium D was first, two Pentium 4 cores
• Core Duo and Core 2 Duo

12
Multi-stuff

• Multiprocessing
• Having two or more CPUs or CPU cores, so you can
  run two or more programs at once
• Multitasking
• Switching between two or more programs so it
  looks like the CPU is doing multiple things at
  once
• Multithreading
• Switching between multiple tasks inside one
  program, can be done while Multitasking

13
Heat

• Produced by pretty much any part that moves
  electricity around (almost all of them)
• CPU, Video Processor, Northbridge, Memory in
  about that order
• Conducted away from parts by heat sinks
• Removed from case by fans
• Builds up if dust, pet hair, etc. clog up case.

14
Memory

• ROM
• Not volatile
• EEPROM, EPROM, PROM, Flash
• Can be re-written, but this is not usually done
• Used to store BIOS settings
• Flash is used in USB thumbdrives

15
Memory

• RAM
• Volatile
• Static RAM SRAM
• Faster, more expensive, no refresh needed
• Used in L1, L2, and disk caches
• Dynamic RAM DRAM
• Slower, cheaper, needs refresh
• Used in main system memory

16
Memory in PCs

• Synchronous DRAM SDRAM
• Comes in DIMMS
• DDR, DDR2, DDR3
• Faster and faster versions of SDRAM
• Rambus
• Comes in RIMMS, Rare and expensive
• Older memory
• SIMMs, SIPPs, DIPs

17
Caching

• Storing a frequently used part of a larger amount
  of data for fast access
• L1 and L2 in processor
• LRU cache
• Disk Cache
• Write-through cache for writes
• Read-ahead caching for reads

18
Standards

• AT and ATX
• Define size and shape of motherboard
• Define placement of mounting holes
• Define power supply size and connection
• ISA, PCI, PCIe
• Define how expansion cards connect
• IDE/PATA, SATA
• Define how drives connect

19
DOS

• Uses a Command Line Interface (CLI)
• Part of Windows 1, 2, 3, 3.11, 95, 98, and ME
• Uses 8.3 file names
• Not much good at networking

20
Windows NT

• Used to be intended mostly for business
• XP and Vista have Home versions too
• Good for servers, working on networks
• NT 3, NT 4, Windows 2000, XP, Vista

21
Mac OS

• Used Graphic User Interface (GUI)
• Mouse, icons, etc.
• Had GUI before Windows existed
• OSX is based on Unix