Unit 3 Assignment 1: Video Summary 1
2) Video one talks mostly about ports and the different kinds of ports that are used in computers today. It also covers what a modem is, its uses, and its speed. Video one teaches us what the difference of a wide SCSI and a narrow SCSI. The video shows all the different ports with all their pins and tells us whether they are male or female. One thing I have definitely learned from this video is what USB stands for and what it actually is. I also learned the difference between USB 1 and USB 2. Video two had a lot to do with computer displays and the different types of screens. In video two I learned the difference between a CRT display and a LCD display, it also talks about what is in both of them. It then goes into the contrast ratio and how the bigger the ratio, the better the video or the display is going to be. I always saw resolutions in my computer but I never knew what they stood for. I now know the standard resolutions and how they work. The video also talks about the video card and if you were building a computer how to know which video card would be worth buying. Video 3 goes into depth about printers and the three most common printers today. It talks about the differences between Dot Matrix, Inkjet, and Laser printers. Since Laser printers are very different from the other two, it went into further depth of the laser printer. The video teaches us multiple ways of how a laser printer can be cleaned. It also tells us major problems that a laser printer would have. At the end of the video it tells us what the queue in a printer is, what is spooling in a printer, and how to improve a printer if it is having certain problems.
3) Video 1: * Serial Port – male, 9 or 25 pins * Parallel ports – female, 25 pins * Game Ports – female, 15 pins with 2 rows * Mouse – serial connector, PS/2 connection, USB or wireless * Keyboard – 5-pin DIN, PS/2 connection, USB or wireless * NIC – Network Interface Card, Converts Parallel communication to serial, uses RJ-45 connector * Modem – connects to phone line, standard speed is 56kbps, converts analog to digital and from digital back to analog, uses RJ-11 connector * VGA – Analog Interface, D-type with 15pins and has 3 rows * DVI - Digital Visual Interface * S-video – Round with 4 or 7 pins, connects to TV * USB – Universal Serial Bus, hot swappable, A-connector, B-connector, 127 simultaneous devices * USB 1 – 12 Mbps, 3 meters * USB 2 – 480 Mbps, 5 meters * Narrow SCSI – 50-pin, type A * Wide SCSI – 68-pin, type P * IEEE 1394 – aka Firewire, Serial, Fast, Hot swappable, used for streaming media, expected to replace SCSI * Multimedia – Microphone, earphones, speaker, color coded
Video 2: * CRT – Cathode Ray Tube, similar to television screens * LCD – Liquid Crystal Display, uses TFT (thin film transistor), also referred to as Active Matrix, backlighting through polarized panels * Screen Size – Diagonal dimension of screen * Contrast Ratio – Ratio of purest white to purest black, bigger is better, 1000:1> 600:1> 400:1 * Refresh Rate – CRT: times per second CRT beam writes to screen, higher number is better * Response Time – LCD: time needed to create new screen, lower number better * Interlacing – CRT: beam writes to alternating lines, compensates for slower refresh rates * Dot Pitch – CRT: distance between phosphorescent dots * Pixel Pitch – CD: addressable pixels on screen, same as resolution * Resolution – both CRT and LCD: addressable points on screen * Standard Resolutions – 640 x 480, 800 x 600, 1024 x 768 * Fixed Resolution – Native Resolution * Resolution – Pixel Pitch * Native Resolutions : XGA - 1024 x 768, SXGA – 1280 x 1024, UXGA – 1600 x 1200, WUXGA – 1920 x 1200 * Analog – 15 pins, 3 rows, D-type, VGA connector * Digital – DVI * S-Video Port – TV * AGP Slot * PCI Express Slot – twice as fast as AGP * Modern Motherboards – several PCI slots, AGP or PCI Express * Buy reputable brand – more expensive, better performance * Check bus type and speed – faster is better * Check Video RAM on card – more is better * Wavy image or screen flicker – may be EMI (Electromagnetic Interface) * Common sources – Fluorescent lights, audio speakers Video 3: * Dot Matrix: An Impact Printer – Clusters of pins strike an inked ribbon * Used in printing multi-part forms * Tractor feed system * Slow and noisy * Paper jams * Ink Jet: Thermal Bubble – uses heat to force ink through nozzle * Piezoelectric Technology – uses electric charge to force ink through nozzle * Requires special paper * CYMB * Laser – Electrophotographic * Six steps in the laser printing process * Expensive to replace toner cartridges
Cleaning Laser Printers: * Cleaning – cleans toner from drum, leaves drum with neutral charge * Conditioning – applies -600 volts to drum * Writing – laser writes image to drum, image is -100 volts * Developing – Toner is transferred to the image * Transferring – Toner is transferred to positively charged paper * Fusing – Rollers apply heat and pressure to melt toner onto page
Problems for Laser Printers: * Totally White Paper – Paper is not retaining a strong positive charge * Totally Black Paper – Drum not retaining a strong negative charge * Streaking on the Page – Probably low toner * Flakey or brittle print on page – Fuser is not hot enough, Fuser is not applying enough pressure * Garbled text – incorrect driver
Improving Printer Performance: * Add more memory * Move or delete graphics * Lower the resolution
Spooling:
* Sends the print job to the print queue * Stores the print in the memory * Frees the operating system for other activities
Queue:
* A list of print jobs waiting to be printed * Double-click printer icon
4) The videos were very informative and I learned a lot about not only computers but also how they work. It went into a lot of depth of the components and how they play a role in a computer system. I learned about things that I use on a daily basis such as a USB port and a LCD screen/display. I also learned about the standard resolutions, which I also use on a daily basis on my computer. These videos will definitely help me in the future when it comes to my knowledge of a computer system if and when I need it.