Direct :: Computer Science

DirectDirect input methods.In this report I am button to explain the different direct inputmethods starting off with turf out codes.A single barcode number is truly seven units. A unit is eitherblack or white. A unit that is black would display as a bar. A unitthat is white would display as a space. Another way of writing abarcode unit is 1 for a single unit black bar and 0 for a singleunit white space. For instance, the number 1 is composed of theseven units, 0011001 or space-space-bar-bar-space-space-bar.Remember, a single barcode number requires seven units.Also, on a UPC barcode the said(prenominal) numbers on the left-hand side (theManufacturer Code) is coded different than the numbers on theright-hand side (Product Code). The left side numbers are actually theinverted or mirrored codes of the right side numbers, for instancewhat is a bar on the right-side, is a space on the left-side. Theright-side codes are called even mirror symmetry codes because there is aneven numbe r of black bar units. For instance the right-side 6 is101000 - 2 even-numbered black bar units. The left-side is calledodd-parity because there is an odd number of black bar units. Forinstance, the left-side 6 is 0101111 - 5 odd-numbered black barunits. Having different coded numbers for each side allows the barcodeto be scanned in either way.Direct input methods.In the second base part of my report on direct input methods I am going tobe talking about magnetised mark readers.A magnetized stripe reader, also called a magstripe reader, is ahardware device that reads the information encoded in the magneticstripe located on the back of a tensile badge. Magnetic stripe readerscan be read by a computer program through a serial port, USBconnection, or keyboard wedge, and are broadly speaking categorized by theway they read a badge. For instance, insertion readers require thatthe badge be inserted into the reader and then pulled out. Swipereaders require that the badge consider com pletely through the reader.The magnetic stripe on the back of a badge is composed of iron-basedmagnetic particles encased in plastic-like tape. Each magneticparticle in the stripe is a tiny bar magnet about 20-millionths of aninch long. When all the bar magnets are polarized in the samedirection, the magnetic stripe is blank. Information is written on thestripe by magnetizing the tiny bars in either a north or south poledirection with a special electromagnetic writer, called an encoder.The writing process, called flux reversal, causes a change in themagnetic field that can be detected by the magnetic stripe reader.