Secondary Storage

Performance Enhancement

Three ways to improve the performance of hard disks are:-

Dick caching

~A portion of RAM used to speed up access to data on a disk. The RAM can be part of the dick drive itself (sometimes called a hard disk cache or buffer) or it can be general-purpose RAM in the computer that is reserved for use by the disk drive (sometimes called a soft disk cache). While the hard drive's hardware disk buffer is sometimes misleadingly referred to as "disk cache", its main functions are write sequencing and read prefetching. Repeated cache hits are relatively rare, due to the small size of the buffer in comparison to HDD's capacity.


Redundant array of inexpensive disks (RAID)

~Redundant array of inexpensive disks, a category of disk drives that employ two or more drives in combination for fault tolerance and performance. RAID disk drives are used frequently on servers but aren't generally necessary for personal computers. RAID allows you to store the same data redundantly (in multiple paces) in a balanced ay to improve overall performance.

File compression and decompression

~The NTFS file system volumes support file compression on an individual file basis. The file compression algorithm used by the NTFS file system is Lempel-Ziv compression. This is a lossless compression algorithm, which means that no data is lost when compressing and decompressing the file, as opposed to lossy compression algorithms such as JPEG, where some data is lost each time data compression and decompression occur.

End~

The Input and Output

The Input and Output

~Input ports are connections at the back of a computer. Input device are connected to these ports, for example, a Keyboard which is used to type data into a computer.


These are the input and output device :-

Magnetic Inc Character Recognition(MICR)

~Magnetic Ink Character Recognition, or MICR, is a character recognition technology used primarily by the banking industry to facilitate the processing of cheques. The technology allows computers to read information (such as account numbers) off of printed documents. Unlike barcodes or similar technologies, however, MICR codes can be easily read by humans. MICR technology was first demonstrated to the American bankers Association in July 1956, and by 1963 it was almost universally employed in the U.S. On September 12, 1961 U.S. Patent Number 3,000,000 was awarded for the invention of MICR

Optical Character Recognition(OCR)

~Often abbreviated OCR, optical character recognition refers to the branch of computer science that involves reading text from paper and translating the images into a form that the computer can manipulate. The potential of OCR systems is enormous because they enable user to harness the power of computers to acess printed documents. OCR is already being used widely in the legal profession, where searches that once required hours or days can now be accomplished in a few seconds.

Optical Mark Recognition(OMR)

~Optical Mark Recognition (OMR) is the technology of electronically extracting intended data from marked fields, such as checkboxes and fill-in fields, on printed forms. It is generally distinguished from OCR by the fact that a recognition engine is not required. This requires the image to have high contrast and an easily-recognizable or irrelevant shape.

Dot Matrix Printer

~A dot matrix printer or impact matrix printer is a type of computer printer with a print head that runs back and forth, or in an up and down motion, on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter. Unlike a typewriter or daisy wheel printer, letters are drawn out of a Dot Matrix, and thus, varied fonts and arbitrary graphics can be produced. Because the printing involves mechanical pressure, these printers can create carbon copies and carbonless copies.

Plotter

~A device that draws pictures on paper based on commands from a computer. Plotters differ from printers in that they draw lines using a pen. As a result, they can produce continuous lines, whereas printers can only simulate lines by printing a closely spaced series of dots. Multicolor plotters use different-colored pens to draw different colors.

Photo Printer

~A photo printer is a printer (usually an inkjet printer) that is specifically designed to print high quality digital photos on photo paper. These printers usually have a very high number of nozzles and are capable of printing droplets as small as 1 picoliter. Photo printers have increased in popularity in recent years along with the increased use of digital camera.

Fax Machine

~A device that can send or receive pictures and text over a telephone line. Fax machines work by digitizing an image -- dividing it into a grid of dots. Each dot is either on or off, depending on whether it is black or white. Electronically, each dot is represented by a bit that has a value of either 0 (off) or 1 (on). In this way, the fax machine translates a picture into a series of zeros and ones (called a bit map) that can be transmitted like normal computer data. On the receiving side, a fax machine reads the incoming data, translates the zeros and ones back into dots, and reprints the picture.

Internet Telephones

~One of the Internet Telephones which is Skype. Skype is a software application that allows users to make voice call over the ineternet. Calls to other users of the service and, in some countries, to free-of-charge numbers, are free, while calls to other landlines and mobile phone can be made for a fee. Additional features include instant messaging, file transfer and video conferencing.

End of post!!

System Unit

System Unit

Expansion Card

~An expansion card is a printed circuit board that can be installed in computer to add functionality to it. For example, a user may add a new graphics card to his computer to give it more 3D graphics processing power. An audio engineer may add a professional sound card to his machine to increase the computer's audio input and output connections. Users that need more Firewire or USB ports can add Firewire or USB expansion cards, which provide additional connections.The first microcomputer to feature a slot-type expansion card bus was the Altair 8800, developed 1974-1975. Initially, implementations of this bus were proprietary but by 1982 manufacturers of Intel 8080/Zilog Z80-based computers running CP/M had settled around the S-100 standard.

Network Interface Card

~A network interface card is used to connect a computer to an Ethernet network. The card provides an interface to the media. This may be either using an external transceiver or through an internal integrated transceiver mounted on the network interface card PCB. The card usually also contains the protocol control firmware and Ethernet Controller needed to support the Medium Access Control (MAC) data link protocol used by Ethernet.

Cache Memory

~CacheCache (pronounced cash) memorymemorymemory is extremely fast memorymemorymemory that is built into a computer’s central processing unit (CPU), or located next to it on a separate chip. The CPU uses cachecachecache memorymemorymemory to store instructions that are repeatedly required to run programs, improving overall system speed. The advantage of cachecachecache memorymemorymemory is that the CPU does not have to use the motherboard’s system bus for data transfer. Whenever data must be passed through the system bus, the data transfer speed slows to the motherboard’s capability. The CPU can process data much faster by avoiding the bottleneck created by the system bus.

"A cache is a short-term storage place. Main computer memory is wayslower than microprocessor chips, and they can spend most of their timewaiting to get a value from memory to operate on. You could speed upall memory, but this costs lots of money and power. If you can onlyafford to speed up a small fraction of the total memory, it's a goodidea to arrange for the computer to use the fast memory more often thanit uses the slow memory. A memory cache is one way to do this."

Tim Mooney

Plug & Play

~In computing, plug and play is a term used to describe the characteristic of a computer bus, or device specification, which facilitates the discovery of a hardware component in a system, without the need for physical device configuration, or user intervention in resolving resource conflicts.Plug and play refers to both the traditional boot-time assignment of device resources and driver identification, as well as to hotplug systems such as USB and Firewire.

Sockets

~Sockets are used nearly everywhere, but are one of the most severely misunderstood technologies around. This is a 10,000 foot overview of sockets. It's not really a tutorial - you'll still have work to do in getting things operational. It doesn't cover the fine points (and there are a lot of them), but I hope it will give you enough background to begin using them decently.

Chips (Computerchips)

~A computer chip is a small electronic circuit, also known as an integrated circuit, which is one of the basic components of most kinds of electronic devices, especially computers. ComputerComputerComputer chipschipschips are small and are made of semiconductors that is usually composed of silicon, on which several tiny components including transistors are embedded and used to transmit electronic data signals. They became popular in the latter half of the 20th century because of their small size, low cost, high performance and ease to produce.The modern computer chip saw its beginning in the 1950s through two separate researchers who were not working together, but developed similar chips. The first was developed at Texas Instruments by Jack Kilby in 1958, and the second was developed at Fairchild Semiconductor by Robert Noyce in 1958.

Slots

~An opening in a computer where you can insert a printed circuit board. Slots are often called expansion slots because they allow you to expand the capabilities of a computer. The boards you insert in expansion slots are called expansion boards or add-on boards.

Buslines

~In computer architecture, a bus is a subsystem that transfers data between computer components inside a computer or between computers.
Early computer buses were literally parallel electrical buseswith multiple connections, but the term is now used for any physical arrangement that provides the same logical functionality as a parallel electrical bus. Modern computer buses can use both parallel and bit-serial connections, and can be wired in either a multidrop (electrical parallel) or daisy chain topology, or connected by switched hubs, as in the case of USB.

Serial Port

~In cpmputing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time (contrast parallel port). Throughout most of the history of personal computers, data transfer through serial ports connected the computer to devices such as terminals and various peripherals.
While such interfaces as Ethernet, FireWire, and USB all send data as a serial stream, the term "serial port" usually identifies hardware more or less compliant to the RS-232 standard, intended to interface with a modem or with a similar communication device.

Parallel Port

~Parallel port is a simple and inexpensive tool for building computer controlled devices and projects. The simplicity and ease of programming makes parallel port popular in electronics hobbyist world. The parallel port is often used in Computer controlled robots, Atmel/PIC programmers, home automation, ...etc... Here a simple tutorial on parallel port interfacing and programming with some examples.

Universal Serial Bus

~USB (Universal Serial Bus) is a way of setting up communication between a computer and peripheral devices. USB is intended to replace many varieties of serial and parallel ports. USB can connect computer peripherals such as mice, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, flash drives, and external hard drives. For many of those devices, USB has become the standard connection method. USB was designed for personal computers, but it has become commonplace on other devices such as PDAs and video game consoles, and as a power cord between a device and an AC adapter plugged into a wall plug for charging. As of 2008, there are about 2 billion USB devices sold per year, and about 6 billion total sold to date.The USB 1.0 specification was introduced in 1996. It was intended to replace the multitude of connectors at the back of PCs, as well as to simplify software configuration of communication devices. The original USB 1.0 specification had a data transfer rate of 12 Mbit/s.

Firewire Port

~Firewire ports are forms of a serial port that make use of FireWireFireWireFireWire technology to transfer data rapidly from one electronic device to another. The FireWireFireWireFireWire portportport has been in common use since 1995, when Apple, Inc. first began to include the portportport on a number of digital camcorders. Today, the FireWireFireWireFireWire portportport is used on a number of other devices. However, the FireWire port is not just for establishing a connection between various electronic devices and a computer system. In fact, FireWire connections can be created directly between two independent devices. Today, there are small printers manufactured for direct use with a digital camera. Making use of a Firewire port to establish a connection, the original file on the digital camera can be printed out on the printer. This completely eliminates the need for uploading photos to a hard drive and then initiating a printing process.

Careers in IT

Careers in IT...

Webmaster

~Webmaster are usually the one who manage most of the Web operations , and also the person who responsible to maintaining or contructions of the website , such as Web advertising , Web design and etc.

Computer support specialist

~Being a "Computer support specialist" , thier job is to helping people who having problems in thier software , computer tools and more of the problems having in computers . Their are also can be the assit of the software company or Lab assit to help solving problems in people computer .

Technical Writer

~Technical Writer are the one who designs, writes, creates, maintains, and updates technical documentation . Technical Writer are also must be very good in grant writing , proposal writing , and lot's more .

Software Engineer

~They most likely are the one who doing design , development , testing , and evaluation of the software and systems that make computers or anything containing software , such as chips , work .

Network Administrator

~People who is works as Network Administrator , their jobs is to responsible for the maintenence computer hardware and software . Other than that , in company's , Network Administrator also enrole include activities and tasks .

Database Administrator

~As a Database Administrator , they are person who is responsible for the environmental aspects of a database .

System Analyst

~Being a "system analyst" is to responsible for researching , planning , coordinating and recommending software and system choices to meet an organization's business requirements . Other than that , they must very skillfull in many analytical skills .

Programmer

~The Programmer is someone's who writes computer's software , they also wirtes many kinds of code's of softeware .

~JoRDaNZ~