Basic Computer Hardware

Computer Systems

•Components•CPU (s)•RAM = main memory, memory• Input/Output devices•Secondary storage devices

Microprocessor Basics

• A microprocessor (“chip”) is an integrated circuit designed to process instructions• Usually the most

expensive component of a computer

Central Processing Units

• Different types/brands of CPUs (chips)• Intel / AMD the main makers (others like IBM, TI, ARM for mobile devices)• determine what kind of OS and software you can run

• Rated by number of “cores”• Rated by clock speed (MHz)

• “system clock” NOT the calendar on your Desktop• to an engineer, a “clock” is a device that puts out a regular signal• serves the same purpose as a conductor in an orchestra – keeps the components all in sync • measured in Hertz (1 Hz = 1 cycle/signal per second)• Benchmark – software used to test and evaluate CPUs • Overclocking – pushing it beyond rated speeds

• http://cpuboss.com/compare-cpus

CPUs

• Other ways to compare CPUs• Cache memory

• Level 1 (L1) nearest the CPU• Level 2 (L2)• Level 3 (L3) farthest from CPU, shared between several CPUs • typical capacity 10 MB, 16 MB• hits and misses

• Word size • 32 bits or 64 bits• 64 bit usually backwardly compatible, will run older software too

• Other processors• GPU = graphics processing unit

Cache Memory

• Cache memory usually built into chip with CPU• Very short distance for data to

travel• Data that is used repeatedly

stored there temporarily• “cache hits” and “cache misses”

Computers in the Environment• Chip manufacture• Computer chips and CPUs are made of silicon• Youtube

How do they make Silicon Wafers and Computer Chips? (8 mins and linked video - 10 mins)

• Acids, powerful lasers, and hazardous chemicals are used to etch circuitry onto silicon wafers

• Chip production takes place in a clean room to keep chips from being contaminated and to keep hazardous materials from escaping

• Chip production is largely done by robots to keep from exposing humans to the hazards of the plant

Computers and Heat

• Chips can melt if they get hot enough• Keep your computer area and case clean!• Let the air circulate• Vacuum out dust from case • Components all age faster when they are hotter than they should be• Some Motherboards will shut down if they sense the temperature is

too high

• Can you upgrade a CPU?• Depends on the Motherboard, does it have a socket that the CPU will fit?• Usually costs enough that it makes sense economically to buy a new machine

• Overclocking• Pushing the components to operate faster than the manufacturer’s

specifications• Usually causes the components to fail sooner, shortens lifespan

Random Access Memory (RAM)

• Temporary holding area for data, application program instructions, and the operating system instructions• Volatile – needs power to hold its contents (information)• Capacity measured in Megabytes, Gigabytes• PC systems usually have between 2 GB and 8 GB

Virtual Memory If a system doesn’t have enough REAL RAM to hold the programs which you want to run, the Operating System can swap pieces of the programs out to the Hard Drive. They stay there until they are needed by the running of the program. Then they get swapped back into RAM while some code that is NOT being used gets sent out to the Hard Drive.

This is a slower process than having actual RAM on your machine – the hard drive is slower to access than RAM, and the act of swapping is overhead that takes time.

But it makes it possible to run programs which really should not run on your computer.

This is why adding more real RAM to a computer will speed up its processing.

Secondary Storage

• Magnetic storage• Optical Storage• Solid State Storage

Magnetic storage – Hard drives

• Hard drives use magnetic heads to sense very very small magnetic spots on the surface of disks (platters) that are rotating very fast (> 7000 RPM)

• The spots represent binary data• Hard drives should NOT be “jiggled”

around while they are working – the head is moving so close to the disk surface that this can cause a “head crash”

• Head crashes can damage your head, access arm and the data under the head at the time – they can make the drive unusable

Optical Storage

• Optical devices (CD, DVD, Blu-ray) use lasers to read and write on their media• Some devices actually use the

laser to dig microscopic pits in the surface – those are the “R” types – Read – they can’t be erased once written• RW types (Read, Write) use dyes at

different levels in the medium to record and erase data many times

Solid State Storage

• Stores data in patterns of electrons in writeable, erasable circuitry• Started small, with memory (flash) sticks• Now found in SD cards of all sizes and capacities• Also in Solid State drives• Rivals to magnetic drives, speed not quite as fast, prices still high

• No moving parts• Can be changed when it is given power, if power is off data is frozen• Watch out for static electricity with memory sticks and cards!

Peripherals

• Devices added to the main computer to add abilities• input (keyboard, mouse, trackball, Wii controller, microphone)• output (printer, monitor, 3d-printer, speakers)• storage (external hard drives, memory sticks, cameras, phones)

• They are called “peripheral” because they are NOT at the center of the computer (that’s the CPU and RAM)

Display Devices

• An LCD display produces an image by filtering light through a layer of liquid crystal cells• LCD displays need a backlight, to come

from behind the crystal cells, be changed to the desired color and then exit the display and strike your eyes.• Gradually, Cold Cathode FL

backlighting technology is being replaced by low-power light-emitting diodes (LEDs)

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Types of displays

• http://www.rtings.com/info/lcd-vs-led-vs-plasma/how-they-work• LCD + fluorescent back lights• LCD + LED back lights• Plasma• http://www.landrysolutions.com/Plasma_LCD_explainations.htm

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Display Devices

• Screen size• Dot pitch• Width of viewing angle• Response rate• Resolution• Color depth• Power usage• Weight

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Printers

• An ink-jet printer has a nozzle-like print head that sprays ink onto paper• A laser printer uses the same technology as a photocopier (path of paper through

a laser printer in image on right)

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Printers• Printer features• Resolution (dpi)• Print speed (ppm)• Operating costs (cost per page)• Duplex capability (print on both sides of

paper)• Memory for buffer• Networkability

• Recycle or refill?

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Peripherals, slots and ports

Protecting your computer

• Power surges and brown outs• Lightning strikes nearby• Protect your computer with • Uninterruptible Power Supply (UPS) – more expensive, usually also has

battery backup to allow you time to shut the computer down correctly when the power fails. Usually provides better protection, faster fuses. Most have a place to plug in your telephone line also. Phone lines can carry surges too!• Surge suppressor – usually in the form of a power strip with a fuse. They are

cheap, not always fast enough to protect your computer.

Buying a computer

• Decide on the USE of the computer • playing games, school work, social media, web hosting, special needs, business

• Decide on platform = OS and hardware• Apple = Mac, iPhone, iPad• PC = Intel (or compatible) CPU, Windows OS or Linux OS• other special purpose

• Decide on budget• Think about the future

• how long do you want to use this computer?• is there something you will want to do later that you don’t do now?

• Consider your “legacy” • what format are your documents in right now? you want to stay compatible• What kind does your school/work use? you may need to be compatible

E-waste (Computers and Society)

• Recycling electronics is good BUT…• Make sure you know where the waste goes• Many third-world countries accept the waste and do not know how to

handle/treat it• Ewaste is toxic• Who is responsible for recycling the device?• The consumer?• The manufacturer?• The government?

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