Tuesday, 30 December 2014

What is Memory ? Types of Memory $$$

What is Memory ? Types of Memory


1--A modern computer has the following hardware components: input/output devices, processing unit, memory unit and secondary storage. The memory unit is the principal storage of the computer. All the data and instructions that the computer needs at a moment are stored here.



2--Computer memory is any physical device capable of storing information temporarily or permanently. For example, Random Access Memory (RAM), is a type of volatile memory that is stores information on an integrated circuit, and that is used by the operating system, software, hardware, or the user. Below is an example picture of a 512MB DIMM computer memory module.




Two Types of Memory

1--Primary Memory
2--Secondary Memory

1--Primary Memory--  



Primary memory is computer memory that a processor or computer accesses first or directly. It allows a processor to access running execution applications and services that are temporarily stored in a specific memory location.
Definition 2: In the enterprise, primary storage holds data that is in active use.

Primary memory is also known as primary storage or main memory.


2--Secondary Memory--  Secondary memory is computer memory that is non-volatile and persistent in nature and is not directly accessed by a computer/processor. It allows a user to store data that may be instantly and easily retrieved, transported and used by applications and services.

2--Secondary storage : sometimes called auxiliary or external storage, is non-volatile storage that is not under the direct control of a computer’s central processing unit (CPU) or does not directly interact with an application.

Secondary memory is also known as secondary storage.

Types of Primary Memory

(1) ROM :Read only memory--  In this type of memory the information is stored permanently, its is not lost after the system shuts down. The advantage of using this memory is that there are some complex functions like translators that are used repeatedly . These functions are permanently stored in the ROM and these instructions are hard wired in ROM so the execution is very fast.

There are different types of ROM . They are described below

Types of ROM

PROM:Programmable Read only Memory. In this the ROM is programmable but only once. Its just like burning a CD using CD recorder. You have a blank CD you can record what ever you want ,after recording you can read it any number of times.
In a strict ROM the device is constructed with the program already inside. But PROM is produced blank. It is programmed only later. The advantage  of using PROM is that a company can change the program it is going to store when ever they want with out loss of hardware.

Erasable programmable ROM(EPROM): This type of PROM can be erased and reprogrammed a number of times. Here the chip that holds the memory is exposed through a glass widow. A strong UV light of a particular frequency if shined through this glass window will erase the EPROM


Electrically erasable programmable ROM(EPROM): This PROM can be reprogrammed under software control.

(2)RAM:Random Access Memory--
Unlike the ROM this is type of memory is volatile and can erased every now and then. Data can be written to it and may be retrieved from it according to the address given. There are two types of RAM dynamic RAM and Static RAM.

RAM Example-- calculator
Static RAM: Retains its content as long as the power supply is there. Once the power supply is lost it looses its contents.

Dynamic RAM: Cannot retain the data even if constant power supply is there. The life time of data in it is milliseconds.

DRAM controller is used to refresh the data in Dynamic RAM before it starts to fade. So with DRAM controller we can make Dynamic RAM function just like Static RAM.

SDRAM (synchronous DRAM)

SDRAM (synchronous DRAM) is a generic name for various kinds of dynamic random access memory (DRAM) that are synchronized with the clock speed that the microprocessor is optimized for. This tends to increase the number of instructions that the processor can perform in a given time. The speed of SDRAM is rated in MHz rather than in nanoseconds (ns). This makes it easier to compare the bus speed and the RAM chip speed. You can convert the RAM clock speed to nanoseconds by dividing the chip speed into 1 billion ns (which is one second). For example, an 83 MHz RAM would be equivalent to 12 ns.


Friday, 19 December 2014

Generations of Computers

The Five Generations of Computers




First Generation (1945-1956) Vacuum Tubes--

The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.
First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.
The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.




Second Generation (1956-1963) Transistors

Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.
Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.
The first computers of this generation were developed for the atomic energy industry.


Third Generation (1964-1971) Integrated Circuits

The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.
Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

Fourth Generation (1971-Present) Microprocessors

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip.
In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.
As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.


Fifth Generation (Present and Beyond) Artificial Intelligence

Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.


DID YOU KNOW...?

An integrated circuit (IC) is a small electronic device made out of a semiconductor material. The first integrated circuit was developed in the 1950s by Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor.

कम्प्यूटर की पीढ़ी

कम्प्यूटर यथार्थ मे एक आश्चर्यजनक मशीन है। कम्प्यूटर को विभिन्न पीढ़ी मे वर्गीकृत किया गया है। समय अवधि के अनुसार कम्प्यूटर का वर्गीकरण नीचे दिया गया है।
प्रथम पीढ़ी के कम्प्यूटर ( 1945 से 1956)वैक्यूम ट्यूब
द्वितीय पीढ़ी के कम्प्यूटर (1956 से 1963)ट्रांजिस्टर 
तृतीय पीढ़ी के कम्प्यूटर (1964 से 1971) IC(integrated cercuit )
चतुर्थ पीढ़ी के कम्प्यूटर(1971 से वर्तमान)LSI (large scale integrated circuit ) VLSI(very large scale integratd circuit ) ULSI(ultra large scale integrated circuit )

पंचम पीढ़ी के कम्प्यूटर (वर्तमान से वर्तमान के उपरांत) 

प्रथम पीढ़ी के कम्प्यूटर ( 1945 से 1956)


सन् 1946 मे पेनिसलवेनिया विश्वविधालय के दो ईंजिनियर जिनका नाम प्रोफेसर इक्रर्टऔर जॉन था। उन्होने प्रथम डिजिटल कम्प्यूटर का निर्माण किया। जिसमे उन्होने वैक्यूम ट्यूब का उपयोग किया था। उन्होने अपने नए खोज का नाम इनिक(ENIAC) रखा था। इस कम्प्यूटर मे लगभग 18,000 वैक्यूम ट्यूब , 70,000 रजिस्टर और लगभग पांच मिलियन जोड़ थे । यह कम्प्यूटर एक बहुत भारी मशीन के समान था । जिसे चलाने के लिए लगभग 160 किलो वाट विद्युत उर्जा की आवशयकता होती थी।


द्वितीय पीढी के कम्प्यूटर ( 1956 से 1963 ) 

सन् 1948 मे ट्रांजिस्टर की खोज ने कम्प्यूटर के विकास मे महत्वपूर्ण भूमिका अदा की । अब वैक्यूम ट्यूब का स्थान ट्रांजिस्टर ने ले लिया जिसका उपयोग रेडियो ,टेलिविजन , कम्प्यूटर आदि बनाने मे किया जाने undefinedलगा । जिसका परिणाम यह हुआ कि मशीनो का आकार छोटा हो गया । कम्प्यूटर के निर्माण मे ट्रांजिस्टर के उपयोग से कम्प्यूटर अधिक उर्जा दक्ष ,तीव्र एवं अधिक विश्वसनिय हो गया । इस पीढी के कम्प्यूटर महंगे थे । द्वितीय पीढी के कम्प्यूटर मे मशीन लेंग्वेज़ को एसेम्बली लेंग्वेज़ के द्वारा प्रतिस्थापित कर दिया गया । एसेम्बली लेंग्वेज़ मे कठिन बायनरी कोड की जगह संक्षिप्त प्रोग्रामिंग कोड लिखे जाते थे


तृतिय पीढी के कम्प्यूटर (1964 से 1975) 
यद्यपि वैक्यूम ट्यूब का स्थान ट्रांजिस्टर ने ले लिया था परंतु इसके उपयोग से बहुत अधिक मात्रा मे ऊर्जा उत्पन्न होती थी जो कि कम्प्यूटर के आंतरिक अंगो के लिए हानिकारक थी । सन् 1958 मे जैक किलबे ने IC(integrated cercuit ) का निर्माण किया । जिससे कि वैज्ञानिको ने कम्प्यूटर के अधिक से अधिक घटको को एक एकल चिप पर समाहित किया गया , जिसे सेमीकंडकटर कहा गया, पर समाहित कर दिया । जिसका परिणम यह हुआ कि कम्प्यूटर अधिक तेज एवं छोटा हो गया ।

चतुर्थ पीढी के कम्प्यूटर 

सन् 1971 मे बहुत अधिक मात्रा मे सर्किट को एक एकल चिप पर समाहित किया गया । LSI (large scale integrated circuit ) VLSI(very large scale integratd circuit ) ULSI(ultra large scale integrated circuit ) मे undefinedबहुत अधिक मात्रा मे सर्किट को एक एकल चिप पर समाहित किया गया । सन् 1975 मे प्रथम माइक्रो कम्प्यूटर Altair 8000 प्रस्तुत किया गया ।
सन् 1981 मे IBM ने पर्सनल कम्प्यूटर प्रस्तुत किया जिसका उपयोग घर, कार्यालय एवं विघालय मे होता है । चतुर्थ पीढी के कम्प्यूटर मे लेपटॉप का निर्माण किया गया । जो कि आकार मे ब्रिफकेस के समान था । plamtop का निर्माण किया गया जिसे जेब मे रखा जा सकता था


पंचम पीढी के कम्प्यूटर (वर्तमान से वर्तमान के बाद)

पंचम पीढी के कम्प्यूटर को परिभाषित करना कुछ कठिन होगा । इस पीढी के कम्प्यूटर लेखक सी क्लार्क के द्वारा लिखे उपन्यास अ स्पेस ओडिसी मे वर्णित HAL 9000 के समान ही है । ये रियल लाइफ कम्प्यूटर होंगे जिसमे आर्टिफिशल इंटेलिजेंस होगा ।आधुनिक टेक्नॉलाजी एवं विज्ञान का उपयोग करके इसका निर्माण किया जाएगा जिसमे एक एकल सी. पी. यू . की जगह समानान्तर प्रोसेसिंग होगी । तथा इसमे सेमीकंडकटर टेक्नॉलाजी का उपयोग किया जाएगा जिसमे बिना किसी प्रतिरोध के विद्युत का बहाव होगा जिससे सूचना के बहाव की गति बढेगी ।

Wednesday, 10 December 2014

Characteristics Of Computer System

                  Characteristics Of Computer System 


Speed-- Computer can carry out instruction in less than a million of a second.The Speed of the computer measured in nano second(or 10–9  of a second ).


Accuracy--  Computer can do the calculation without errors and very accurately.Perform each and every computation with 100% accuracy.


Diligence--   1-Computer are capable of performing any task given to them repetitively.

                       2- Can perform a task repetitively for N number of times, without any degradation processing speed.


Storage capacity-- Computer can store large volume of data and information on magnetic media.

2-  Can store huge amounts of data within themselves in a limited area.

Versatility-- Computer can be used in many fields of operation, such as Education.Engineering,Medical,Science,Bank etc.




                                                     कंप्यूटर का गुणधर्म 



गति-- कंप्यूटर का सबसे पहला और सबसे बड़ा गुण गना करने की उसकी तीव्र गति ही है । वास्तव मे कंप्यूटर का निर्माण ही तेज गति से गना करने वाली एक मशीन के रूप में किया गया था । प्रारम्भिक कंप्यूटर भी गनाये करने मे इतनी तेज थे की कि हम सोच भी नहीं सकते । जैसे-जैसे इलेक्ट्रॉनिक का विकास होता जा रहा है, वैसे-वैसे कंप्यूटर की गति बढती जा रही है ।  




शुद्धता--    कम्प्यूटर बहुत ही शुद्ध मशीन है । यह जटिल से जटिल गणनाएँ बिना किसी त्रुटि के करता है ।




परिश्रमशील--   तापरिश्रमशीलता का अर्थ है कि बिना किसी रूकावट के कार्य करना । मानव जीवन थकान ,कमजोरी,सकेन्द्रण का आभाव आदि से पिडित रङता है।मनुष्य मे भावनाए ङोती है वे कभी खुश कभी दुखी होते है । इसलिए वे एक जैसा काम नही कर पाते है । परंतु कम्प्यूटर के साथ ऐसा नही है वह हर कार्य हर बार बहुत ही शुद्धता एवं यथार्थता से करता है .




वर्ड-लेन्थ--डिजिटल कम्प्यूटर केवल बायनरी डिजिट पर चलता है। यह केवल 0 एवं 1 की भाषा समझता है। आठ बिट के समूह को बाइट कहा जाता है । बिट की संख्या जिन्हे कम्प्यूटर एक समय मे क्रियान्वित करता है वर्ड लेंन्थ कहा जाता है । सामान्यतया उपयोग मे आने वाले वर्ड लेन्थ 8,16,32,64 आदि है। वर्ड लेन्थ के द्वारा कम्प्यूटर की शक्ति मापी जाती है।




स्वचलन--   कम्प्यूटर एक समय मे एक से अधिक कार्य करने मे सक्षम है ।








                                                           

Sunday, 7 December 2014

What is Computer and Data ?English and Hindi definition....

Computer definition English and Hindi---

1--  A Computer is an electronic Machine (not Device) for processing data.


2--  The definition of a computer is a person or electronic device that makes and stores     quick calculations or processes information.


कंप्यूटर  परिभाषा --    कंप्यूटर शब्द की उत्पत्ति कंप्यूट शब्द से हुई है जिसका अर्थ है गणना करना ‍‌। अतः बोलचाल की भाषा मे इसे एक काल्कुलेटिंग डिवाइस माना जाता है जो एरथमेटिक और लजिकल आपरेसन को तेजी के साथ कर सकता है । कंप्यूटर को एक इलेक्ट्रॉनिक मशीन कहते है इसको डिवाइस नहीं कहा जा सकता क्यूंकि मशीन  प्रोसेस करता है और डिवाइस प्रीसेस नहीं करता है उसका लगातार मैन पॉवर की अवश्यकता पड़ती है ।


Computer Full Form---   Commonly Operated Machine Particularly Used for Technology Education and Research



कंप्यूटर का हिंदी अर्थ-    संगणक 


DATA--(आकड़ा)     The data is fed as an input to the computer,stored and further processed as per the instruction provided,so as to generate an input.


DATA--(आकड़ा)   निर्देश तथा सूचनाएँ, जिन्हें कंप्यूटर में स्टोर या अन्य कार्यों को करने के लिए प्रयोग किया जाता हैं.