Thirteen Ways of Looking at a Parabola

Math with Bad Drawings

with sincere apologies to Wallace Stevens,
and to all poets, everywhere


All my life
I had known only lines
so when my teacher
drew a parabola
I said,



I took all the numbers,
and squared them.
The big ones grew.
The little ones shrank.
The negative ones
became positive.
Opposites agreed.
It was kinda cool.




I watched an object falling,
tracing its arc,
the ink of time leaving curves
on the paper of space—
a perfect parabola.
(Except for air resistance.)


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“A rigid non-removable magnetic disk with a large data storage capacity.”

There are several different types of hard drives for storing software and data files: hard disk drives, solid-state drives and external drives. Learn about how they work and how to select the right drive for a particular computer system.




You may have experienced this scenario: you turn on your computer and you get a black screen with the message ‘Imminent Hard Disk Failure’. Or you’ve dropped your laptop on the floor, your screen goes black and your computer won’t turn back on again. More often than not the problem is your hard drive. If your hard drive has crashed, you may have lost all your documents, photos, music, etc. It can be one of the more frustrating experiences for any computer user. Read on to learn how your hard drive works, and some simple steps you can take to avoid losing all your files if it crashes.


There are two general types of hard drives:


  1. hard disk drives

    (HDD):,which use one or more rotating discs and rely on magnetic storage, and


  1. Solid-state drives

    (SDD):, which have no moving mechanical parts but use flash memory like the kind found in USB flash drives.



Hard disk drives (HDD):

Hard disk drives have been the dominant type of storage since the early days of computers. A hard disk drive consists of a rigid disc made with non-magnetic material which is coated with a thin layer of magnetic material. Data is stored by magnetizing this thin film. The disk spins at high speed and a magnetic head mounted on a moving arm is used to read and write data. A typical hard disk drive operates at a speed of 7,200 rpm (rotations per minute), so you will often see this number as part of the technical specifications of a computer. The spinning of the disk is also the source of the humming noise of a computer, although most modern hard disk drives are fairly quiet.


 In general, hard disk drives are very robust and can be used for many years without problems. However, hard disk drives can fail and one of the most common reasons is a head crash. This occurs when the magnetic head scratches the magnetic film. This typically happens as a result of a physical shock, like dropping a computer while it is on. When your hard drives experiences mechanical failure you can often hear a grinding or scratching sound. Such as crash results in data loss since the magnetic film gets damaged. It is therefore always a good idea to have a backup copy of the important files on your hard drive.


Solid-state drives (SDD):

Solid-state drives (SDD) are a relatively new alternative to more traditional hard disk drives. Solid-state drives do not have moving parts, and data is stored electrically instead of magnetically. Most solid-state drives use flash memory, which is also used in memory cards for digital cameras and USB flash drives. Since there are no moving parts, solid-state drives are much less vulnerable to damage from physical shock. The major downside of solid-state drives is that they are a lot more expensive than hard disk drives, although prices are gradually coming down.


Despite the cost, solid-state drives are quickly becoming the preferred type of hard drive for certain types of computers because they are very damage proof and smaller than regular hard disk drives. For example, the MacBook Air now comes standard with a solid-state drive using flash memory.



Capacity and performance:

The most important characteristic of a hard drive is how much data it can store, referred to as the storage capacity. A typical internal hard drive for a new desktop computer or laptop has a storage capacity of several hundred gigabytes (GB) up to 1 terabyte (TB). How large is a terabyte? Consider that a typical song in MP3 format is in the order of 5 to 10 MB. You could store approximately 150,000 songs on a 1 TB drive.


The branch of technology that deals with the design, construction, operation, and application of robots.

A Short History of Robots

Robot Timeline:

  • ~270BC an ancient Greek engineer named Ctesibus made organs and water clocks with movable figures.
  • 1818 – Mary Shelley wrote “Frankenstein” which was about a frightening artificial life form created by Dr. Frankenstein.
  • 1921 – The term “robot” was first used in a play called “R.U.R.” or “Rossum’s Universal Robots” by the Czech writer Karel Capek. The plot was simple: man makes robot then robot kills man!
  • 1941 – Science fiction writer Isaac Asimov first used the word “robotics” to describe the technology of robots and predicted the rise of a powerful robot industry.
  • 1942 – Asimov wrote “Runaround”, a story about robots which contained the “Three Laws of Robotics”:
    • A robot may not injure a human, or, through inaction, allow a human being to come to harm.
    • A robot must obey the orders it by human beings except where such orders would conflict with the First Law.
    • A robot must protect its own existence as long as such protection does not conflict within the First or Second Law.
  • 1948 – “Cybernetics”, an influence on artificial intelligence research was published by Norbert Wiener
  • 1956 – George Devol and Joseph Engel berger formed the world’s first robot company.
  • 1959 – Computer-assisted manufacturing was demonstrated at the Servomechanisms Lab at MIT.
  • 1961 – The first industrial robot was online in a General Motors automobile factory in New Jersey. It was called UNIMATE.
  • 1963 – The first artificial robotic arm to be controlled by a computer was designed. The Rancho Arm was designed as a tool for the handicapped and it’s six joints gave it the flexibility of a human arm.
  • 1965 – DENDRAL was the first expert system or program designed to execute the accumulated knowledge of subject experts.
  • 1968 – The octopus-like Tentacle Arm was developed by Marvin Minsky.
  • 1969 – The Stanford Arm was the first electrically powered, computer-controlled robot arm.
  • 1970 – Shakey was introduced as the first mobile robot controlled by artificial intellence. It was produced by SRI International.
  • 1974 – A robotic arm (the Silver Arm) that performed small-parts assembly using feedback from touch and pressure sensors was designed.
  • 1979 – The Standford Cart crossed a chair-filled room without human assistance. The cart had a tv camera mounted on a rail which took pictures from multiple angles and relayed them to a computer. The computer analyzed the distance between the cart and the obstacles.

Advantages and disadvantages of robotics


  • You can send them to very dangerous places
  • You can make them do you’re job for you
  • They are more accurate than humans Eg no shaking when in a very important surgery, puts every screw in fabricating a car etc.
  • Can do jobs 24/7
  • Can guard without being tired just keep doing the same thing 24/7
  • No need of nutrients
  • You can programme them to make them do exactly what you want them to do
  • They cannot harm you unless they are programmed to
  • Can work without doubts Eg when you think “what do i do now”?
  • They can lift very heavy things


  • You need to get people trained to fix them if anything wrong happens
  • Need a very intelligent crew
  • They can ruin people lives Eg Take their job away from them
  • They are very expensive to make
  • You need the right materials to make them, that could be very rare
  • If you make a very amazing robot with amazing quality and it brakes, it might be very hard to fix
  • They can be very hard to program.
  • They can reproduce but it could cost money for the materials
  • You need highly trained people to make them
  • They cannot recharge themselves


All these facts about robots may interest you………………………..!

Artificial Intelligence (AI)

Definition – What does Artificial Intelligence (AI) mean?

Artificial intelligence (AI) is an area of computer science that emphasizes the creation of intelligent machines that work and react like humans. Some of the activities computers with artificial intelligence are designed for include:

  • Speech recognition
  • Learning
  • Planning
  • Problem solving

explains Artificial Intelligence (AI)

Artificial intelligence is a branch of computer science that aims to create intelligent machines. It has become an essential part of the technology industry. Research associated with artificial intelligence is highly technical and specialized. The core problems of artificial intelligence include programming computers for certain traits such as:

  • Knowledge
  • Reasoning
  • Problem solving
  • Perception
  • Learning
  • Planning
  • Ability to manipulate and move objects

ai4 nao-robots-and-artificial-intelligence Knowledge engineering is a core part of AI research. Machines can often act and react like humans only if they have abundant information relating to the world. Artificial intelligence must have access to objects, categories, properties and relations between all of them to implement knowledge engineering. Initiating common sense, reasoning and problem-solving power in machines is a difficult and tedious approach. Machine learning is another core part of AI. Learning without any kind of supervision requires an ability to identify patterns in streams of inputs, whereas learning with adequate supervision involves classification and numerical regressions. Classification determines the category an object belongs to and regression deals with obtaining a set of numerical input or output examples, thereby discovering functions enabling the generation of suitable outputs from respective inputs. Mathematical analysis of machine learning algorithms and their performance is a well-defined branch of theoretical computer science often referred to as computational learning theory. Machine perception deals with the capability to use sensory inputs to deduce the different aspects of the world, while computer vision is the power to analyze visual inputs with few sub-problems such as facial, object and speech recognition. robot Robotics is also a major field related to AI. Robots require intelligence to handle tasks such as object manipulation and navigation, along with sub-problems of localization, motion planning and mapping. 20111105_STP503

What are Printers and its Types?

Printer is the most popular output device used today to produce hard copy output. There are many types of printers which are used by the users as according to their need. These are very useful nowadays as all the things which are uneasy to read on the monitor screen we used to print those things and read carefully. Below we describe the various types of Printers:

Dot-Matrix Printer:

It is a character printer that print one character at a time. This Printer can form characters and all kinds of images as pattern of dots. Since dot matrix printer produce printed output as pattern of dots, they can print any shape of character that a program can describe. They therefore, can print many special characters, different sizes of print, and also have the ability to print graphics such as charts and graphs.

Dot Matrix Printer

Dot Matrix printer are normally haves slow printing speeds ranging from 30-600 characters per second. They are available at very low cost. These types of printers are generally used to print the shipping invoices.

Inkjet Printers:

It prints characters by spraying patterns of ink on the paper from a nozzle or jet that can heated up selectively. The ink comes out of the nozzle in a form of vapors. After passing through a reflecting plate, it forms the desired letter/shape at the desired place. It is also a Character printer but it produces high quality output than dot matrixprinters because these printers form characters with very tiny ink dots.

inkjet printer

Inkjet printers are slower than dot matrix printer as inkjet printing speed is 40- 300 characters per second. Inkjetprinter is also more expensive than dot matrix because it produces the high quality prints with more transformed technology. These printers are very popular because they are less expensive than laser printers and can print faster and accurate than dot matrix and other impact printers.

Drum Printer:

Drum printer is a line printers that print one line at a time. In addition the drum printer is also the impact printer. In this Printer it has a set of  hammers mounted in front of the drum in a manner that an inked ribbon and paper can be placed between the hammers and the drum. Than the drum rotates at a high speed. A character is printed at a desired print position.

Drum Printer

This printer has the speed of 300- 2000 lines per minute. This printer also produces lots of noise that’s why cover is used to reduce the noise.

Chain Band Printer:

Chain/Band printer are line printers that prints one line at a time. It consist of of a metallic chain/band on which all characters of the character set supported by the printer are embossed. A standard  character set may have 48,64 and 96 characters. The characters in the character set are embossed several times on the chain/band.

Chain band printer

Unlike drum printer the chain/band printer can be changed easily. It allows the printing to be done in different fonts and styles in the same printer. Due to the impact printing chain/band printers are noisy in operation and often use a cover to reduce the noise level. Printing speeds of the chain/band printers range from 400 – 3000 lines per minute.

Laser Printers:

Laser printers are the page printers that prints one page at a time. main component of the laser printer are a laser beam source, multi sided mirror, a photoconductive drum, and toner. Laser printers produces high quality output because they form characters by very tiny ink particles. The high end laser printer can have a resolution of 1200 dpi. Due to the high resolution , these printers give excellent graphics art quality.


Laser printers are faster than other printers discussed earlier. Low speed laser printers can print 4 to 12 pages per minute. Owing to their better print quality and printing speed, laser printers are more expensive than the othertypes of the printers. These printers are very popular in the market because of its fast printing.

Types of Memory Chips

memory chip is a small computer device used to store information, data or a program that is run on a computer or other electronic device that runs like a computer, such as a camera or video game console. There are several different types of memory chips, although some are more commonly used than others


  • Dynamic random access memory chips or DRAM chips is a memory cell requiring refreshing because it transits only single lines of memory. A DRAM chip has numerous small capacitors that contain each memory bit. DRAM chips do not hold change and need to be refreshed in order to keep the contents on the chips from being lost. DRAM chips are commonly referred to as volatile memory chips because they lose their memory when power is lost. DRAM chips are used in some computers that are constantly hooked to power supplies.



    • SRAM chips are static random access memory chips. SRAM chips are non-volatile memory chips and do not require refreshing or power to keep memory intact. SRAM chips are most common in portable battery powered devices like laptops, cameras, cell phones and video game consoles



    • FIFO memory chips or First-In First-Out memory chips are used in applications that are used between different devices. The devices work at different speeds, so the FIFO memory chips are necessary to buffer the memory between the two devices. Flash or jump drives that are used to transport memory between different computers and types of computers use FIFO memory chips.



    • EPROM chips are erasable programmable read-only memory. These types of memory chips can be erased when they are exposed to ultraviolet light. When erased, the ERPOM chips can then be reprogrammed to contain a new set of data or reused to house a different program. A variation of this type of memory chip is the EEPROM chip that can be erased electronically rather than with UV light.



      • PROM chips are programmable read-only memory chips that differ from other programmable read-only memory chips because they can only be written to once. PROM chips cannot be erased with UV light or electronically.


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The Different Types of Computer Mice

Computer mice some in a number of varieties. You can find a computermouse for just about any use. To figure out what kind of mouse would work best with your PC, you need to know your mouse options:

  • Mechanical mouse: Houses a hard rubber ball that rolls as the mouse is moved. Sensors inside the mouse body detect the movement and translate it into information that the computer interprets.


Optical mouse: Uses an LED sensor to detect tabletop movement and then sends off that information to the computer for merry munching.


Infrared (IR) or radio frequency cordless mouse: With both these types, the mouse relays a signal to a base station wired to the computer’s mouse port. The cordless mouse requires power, which comes in the form of batteries.wireless-mouse-570

A mouse with many buttons: The extra buttons can be programmed to do specific things, such as navigate the Web or turn pages when you’re reading a document. The typical button-ified mouse has about five buttons.


Trackball mouse: Like an upside-down mouse. Rather than roll the mouse around, you use your thumb or index finger to roll a ball on top of the mouse. The whole contraption stays stationary, so it doesn’t need a lot of room, and its cord never gets tangled


  • Stylus mouse: Another mouse mutation enjoyed by the artistic type is the stylus mouse, which looks like a pen and draws on a special pad.


  • Cordless 3-D mouse: This kind of mouse can be pointed at the computerscreen like a TV remote.