Hardware and Software

Hardware and Software

Basic Hardware • Hardware vs. Software • Hardware includes • CPU = central processing unit • Memory = RAM (random access memory) • Input = Keyboard, mouse, microphone • Output = Screen, speaker, printer • Storage = Hard drive, DVD, Solid State • Volatile vs. non-volatile • Memory and the CPU are volatile – they lose their contents when the power cuts off • Storage is NON-volatile – they maintain their contents until you erase them

Processor 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 are the main makers (others like IBM, Texas Instruments, ARM for mobile devices) • The type determines what kind of OS and software you can run • Rated by clock speed (MHz, GHz) • The “system clock” is NOT the calendar on your Desktop • 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 synchronized • measured in Hertz (1 Hz = 1 cycle/signal per second) • 1 MHz = 1 million cycles/second, 1 GHz = 1 billion cycles/second • http://cpuboss.com/compare-cpus

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” • Analogy: CPU is your kitchen, memory is your pantry, the hard drive is the grocery store

CPUs • Other ways to compare CPUs • Cache memory • Level 1 (L1) nearest the CPU, usually on the same chip as 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 – refers to the size of the numbers the CPU can handle at one time • Which is also the size of the registers in the CPU • 64 bit usually backwardly compatible, will run older software too • Other processors • GPU = graphics processing unit

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 16 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 can’t be run in your computer’s memory. This is why adding more real RAM to a computer will speed up its processing, not so much swapping in and out.

Secondary Storage • Magnetic storage • Optical Storage • Solid State Storage

Magnetic storage – Hard drives • Hard drives use magnetic heads to sense 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 the 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 • First models could only be read by consumer drives – CD ROM, DVD ROM (read only memory) • 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 (used in cameras) • Also in Solid State drives (SSD) • Rivals to magnetic drives, speed quite a bit faster than HD, 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! Put the cap on or withdraw the part that sticks out to plug in the USB port.

Solid State Devices versus Hard Drives SSD Hard drive + Cheaper per terabyte + Available in larger capacities - Will fragment files - Head crashes - Some noise is inevitable - Probably not going to get smaller - Lifespan – eventually does wear out • - More expensive • + Faster • + Less likely to fragment files • + Tougher – no head crashes! • + Quieter – no moving parts • + Smaller and getting smaller • - Lifespan – each cell can only be written so many times

Comparing SSD and Hard Drives • http://www.pcmag.com/article2/0,2817,2404258,00.asp • Lifespan of either device is probably not going to be the determining factor in the lifespan of the computer as a whole • People get new machines before their HD or SSD wears out • Some manufacturers thinking of hybrid devices – Hard drive for capacity and then a smaller SSD for a buffer to the HD • Cloud storage is going to make both of these less important to the computer

Computers and the Environment • Chip manufacture • Computer chips and CPUs are made of silicon • YoutubeHow 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 – don’t cover up the slots on the case • 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 –sometimes without a warning!

Computer Types • Supercomputers • Very fast, usually used in research – simulations, code breaking, chess • Mainframes (enterprise servers) • Millions of transactions a day, large companies, government agencies • Servers • server farms • Personal Computers (desktop and laptop) • Tablets and e-readers • Smart phones

Common input devices • Qwerty keyboard • Connected through USB port • Most efficient for entering large amounts of data • Mouse • Mainly used with GUI (graphical user interface) • Pointing to objects on screen • Optical technology • Wireless mouse requires dongle – receiver in a USB port • Touchpad • Replaces mouse pointer • Touchscreens • Intended for human skin • Speech input • Speech recognition is hard for computers • Good in hands-free environment but not too accurate

Common output devices - Displays • Display Technology • Liquid Crystal Display – lightweight, lower power usage, polarized (viewing angle) • Plasma – better contrast, higher power usage • Pixels in red, green and blue • Aspect ratio – ratio of width to height (4:3 or 16:9) • Resolution – 1600 x 900 means 1600 pixels wide, 900 pixels high • Color depth – number of bits to store a pixel’s color

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. • Light is polarized as it travels from the light source, so that it is coming straight out of the screen. If you view it from an angle, it is hard to see. Chapter 2: Computer Hardware

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) Chapter 2: Computer Hardware

Printers • Color printers use CMYK = cyan, magenta, yellow, black (K) • Laser printers are faster than ink jet printers, usually more expensive • Printer resolution measured in DPI, dots per inch • Printer speed measure in PPM, pages per minute • Duplexing is a printer that can print on both sides of the paper • Printers have RAM to act as a buffer, to hold a document until the printer can print it • Consider what you will do with the ink cartridges or toner cartridges. If possible, you should refill or recycle them.

Audio output devices • Speakers • Music, sound, speech • Easy for the computer to turn numbers into sounds • Most computers these days have built-in speakers • You can buy separate systems for better quality • Please use headphones or earbuds to listen if you are in a crowded environment

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.

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? Chapter 2: Computer Hardware

Rare Earth Metals in electronics • Elements like yttrium and praseodymium (17 of them) • used in many different kinds of electronics: smart phones, speakers, radar systems, missiles, wind turbines, electric cars • mined from the earth but with difficulty – usually mixed with much other material – processing causes huge amounts of toxic waste • US consumes 20,000 tons, Europe 7000 tons, Japan 24,000 tons, China 104,000 tons / yr • China produces 80% of the market, recently cut off supplies to Japan over territorial dispute • Some other deposits – Russia, India, Australia, US • http://foreignpolicy.com/2016/07/12/decoder-rare-earth-market-tech-defense-clean-energy-china-trade/

Hardware Trends • Server farms / data centers • As demands for the internet and the Cloud increase, big companies build huge buildings full of servers. Take lots of power, cooling • Multi-core chips • Have the circuitry for two or more CPUs on the same chip • Quad core = 4 CPU’s • 8 and 16-core chips coming onto the market • Independent processors for specialized tasks • Some printers have processors to speed up processing documents • GPU = graphics processing unit, specially for drawing graphics quickly

Hardware Trends • “Dark Data” center • a facility that is almost exclusively administered remotely, so there is no reason to have lights on in the rooms – hence “dark data” • Are continuously monitored not just for data issues but temperature and humidity • Common tasks that would normally need a person to be there physically can be automated • Benefits include energy and staffing savings • Can be located in a remote area which can also lower costs and increase security

Hardware and Software