Fundamentals
What is computer
Equipment such as the name suggests, are of devolop calculation and calculations. The word "team" comes from the Greek word"Calculate" to calculate the means. However, computers are commonly used today as a non-numerical goals, graphics, music and word, as numerical calculations. Eleconic computer is a device that can receive, store and process data in a ste of instructions stored on it to turn off the genarate
The data could be almost any thing like
· the names, Register numberas and marks of student in class,or
· it could be a song , apiture, a movie or a document
· It could be the temperature and pressure on defferent parts of a spTh blood pressure .ace -craft
· the blood pressure , ECG and other vital parameters of a patient in the I.C.U of a hospital or
· The photo, figer and other details of a suspected criminal
There are other type of computer like analogue Computers and hybrid Computers.
But use of such computers is so specialized and limitted that only specialists need know about them. in our discussions the term ' Copmputer' will always mean Digital Computers only. Computer store all data as number is electonic circuits inside them. since electonic circuits have two distinct ( ON & OFF) which is easly produced and detected, a number system based on two digits is used for representing numbers in the computer This system of numbers which has only two digits is known as Binary digits is called a bit (as the short form binary digits)
Super computers
Super computers Are the most powerfull Computers amoung Digital Computers. These Computers consisit of several processors running together thereby making them immensely fast and powerfull . The speed of a super computers is generally measured in “FLOPS” ( Floating point oparations per second). The are multisure, Multitasking System. Super Computers are mainly used for whether forecast , spaceexiperiments, earthquake studies, modeling of nuclear devices and explosions. Etc.
In November of 2005IBM’s Blue Gene/L has been named the most p[owerful super computer in the World by TOP500 Organization, the world’s foremost upper computing authority. The Blue Gene/L set a record of sorts, with 1,31,072 nodes . PARAM and ANURAG are super computers produced by india and they were developed and manufactured by center fro development advanced computing. ( C-DAC pune.
MainFrame computers
Mainframe computers are designed to handle huge voloumes of data and information. These can support more than hundred users at a time . These are very large and expencive computers have great processing speed and very large storage capacity and memory as compared to micros and minis. They even have multiple processors. Examples are : ICL 39 , CDC 6600, IBM 4381 etc…
Mini computers
Micro computers are computers more powerful than micro computers
They are mainly multiuser systems where many users simultaneously work on them. Microcomputers Prossess greater storage capacity and larger memories compared to micros. Examples are PDP-11,VAX7500 MAGNUM etc...
Micro computers
Mirocomputer is a computer in which the cpu is a micro processor , which is an integrated circuit in which all the components of the central processor are integrated on single chip. They are single designed by performing basic oparations like educational training smll business applications playing games et… IBM PC’S Apple Mac, IBM PS/2 are some popular On this Range
Desktop computers
Almost All computers used in homes and offices came under this category. These are very popular computers. They are designed tobe used on av desk or table with a separate keyboard and mouse for input .At the moment there are two main types of desktop computers available : The IBM PC or its clones and the mac (made by apple computers)
Pocket computer ( palm top computer)
The pocket PC is “a handheld device that enables users to store and retrieve e-mail, contacts , appointments , tasks, play multimedia files, games exchange text messages with windows live messenger (msn messenger) , brows the web and more “ A pocket computer hasbuilt in batteries that lst a long time and the whole computer is light and small enough to be carried around in someone’s pocket. One problem with small computers is that they don’t have full sized keybords attached. They often use special pens called stylus and touch- sensitive screen to enter data
Laptop
Laptop is portable computer which has a flat LCD screen and usually weighs less than2 kilograms. Often called just “laptop’ it uses batteries for mobile use and AC power for charging the batteries and esktop use. Today’s high-end laptops provide all the capability of most desktop computers . which the sharp fall in prices and futures comparable t desktop computers it is belived that within a few years laptop and note book computers give mobility and great saving in power consumption. While a typical desktop computers consumes more than 200 watts, a laptop consumes only 30 to 40 watts. Laptop do not require ups whereas desktop computers need ups , there by increasing the system complexity and cost.
RAM
The main memory of a computer is called the ram . This is the working memory of the computer . The contents of the memory are lost when the power is turn off. The amount of the time that the ram takes to write data or read it ones the request has been received from the processor is called the access times vary from9 nanoseconds to 70 nanoseconds, depending on the kind of ram . although fewer nanoseconds is better , user-percieved performance is based on co-ordinating access times with the computer’s
Clock cycles . Access time consists of latency and transfer time . latency is the time to co-odinates signal timing and refresh data after reading it.
Video ram
Video ram means is general all forms of RAM used to store image data for the video display monitors. All type video ram are special arrangements of dynamic ram Digital to analog converter(RAMDAC) into analog signals that are sent to the display presentation mechanism such as a cathode ray tube (CRT). Usually , video ram comes in a 1 or 2 megabytes packageand is located on the video or graphics card in the computer. Most forms of video RAM are duel-ported . While the processor is writing a new image to video ram , the display is reading from video to refresh is current display content . The duel port design is the main defferents between main storage RAM and viseo RAM
ROM
ROM maens read only memory and is the “built-in” computer memory containing te programmes that allowthe computer to be booted up or regenerated each time we turned it on. Unlike a computer power is turnec off.
Rom by its nametself is upposed tobe that the content cannot be changed , there are times when being able tochange the contentsof rom ca be very useful . there are several rom varients thet can be changed under certain circumstances these can be thought of as “most read only memory” the following are defferent type of ROM’s with adescriptionof tere relative modifiability
In a regular ROM contents are built in at the time of manufacture itself and the content0 cannot be changed this is inflexible and regular ROMs are only used generally for programme that are statics (not changing often) and mass-produced . this product is an analogous to a commercial software CD-ROM that u purchased in store.
Cache memory
A cahe memory is place store something temporarly. The files you automatically request by looking at a web page are stored on your hard disk in a cache subdirectory for your browser under the directory for your browser. When you a return to a page you’ve recently looked at the browser can get it from the cache rather than the originalserver, saving you and the network the burden of some additional traffic. You can usually vary the size of your cache, depending on your particular browser. Two types of catching are commonly used in personal computers
Memory caching
Disk caching
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