Memory and its Types

     What is Computer Memory? 

   Ans: A Computer memory is just like a human brain. A human Brain store data and information also like a  Computer memory store data and information. It is a physical device capable of storing information temporarily or permanently. In other words, it is called a storage space or like a storage container where we are store data and information. 
  There are two types of Computer Memory: Primary Memory and Secondary Memory
    1. Primary Memory: Primary memory is a volatile memory. It is stored only those data and instructions when a Computer is currently on. It is a small storage capacity memory and data is lost when the computer power is switched off. 
     Primary memory primarily three types:
     i. Cache Memory: Cache memory is a very high-speed memory. It acts as a buffer between the main memory and the CPU.

1. It is the fastest memory of the computer system.
2. It is inbuilt in the processor.
3. It is a supplementary of RAM.
4. It is also called CPU memory

ii. Random Access Memory(RAM)

1. Random Access Memory.
2.  It is the Main Memory.
3. Temporary Memory.
4. Volatile Memory.
5. It is display Memory
6. It is sometimes called physical memory.

Types of RAMs: DRAM (Dynamic RAM) and SRAM (static RAM)

DRAM:

1. DRAM requires periodic refreshment.
2. It is slower and dynamic in nature.
3. More power consumes and cheaper.

SRAM:

1. SRAM retains data bits without periodic refreshment.
2. It is slower and dynamic in nature.
3. More periodic refreshment.

iii. Read Only Memory(ROM):

1. Read-Only Memory.
2. It is called BIOS Chip.
3. It is a permanent memory.
4. Non Volatile Memory.
5. It is also called Firmware.
6. It performs the Booting Process and POST process.

Types of ROM:- PROM, EPROM, EEPROM.

PROM:-Programmable Read Only Memory.

EPROM:-Erasable Programmable Read Only Memory

EEPROM:- Electronically Erasable Programmable Read Only Memory.

2. Secondary Memory:

Secondary Memory:-It is where programs and data kept on a long-term basis. It is a large volume storage device. It is also called permanent memory and Auxiliary memory.

Example: Hard Disk Drive, CD, DVD, etc.

HDD:- Hard Disk Drive –(40GB, 80GB, 500GB,1TB)

FDD: Floppy Disk(1.44MB)

CD:- Compact Disk(700MB)

DVD:- Digital video Disk Digital Versatile Disk (4.7GB)

SD Card :- Secure Digital (1GB, 2GB, 4GB, 8GB,16GB, 32GB, 64GB)

PD:-Pen Drive (1GB, 2GB, 4GB,16GB, 64GB)

On the Basis of storing Technique, memory is three types:

1. Magnetic Memory :(Use tiny magnetic spots.)It is two types:

a. Magnetic Tape (Analog Data –Reel used in camera and Cassettes.) and

b. Magnetic Disk (Digital Data- Floppy Disk, Hard Disk)

2. Optical Memory: (Tiny hole pits on reflective metal layer coated in plastic). Example:- CD, DVD

3. Semi-Conductor Memory: (Uses transistor and registers for storage). Example: ROM, PROM, and RAM.

Another Kind of Memory is :

Flash Memory: Flash memory is a kind of memory that retains data in the absence of power supply.

Example:- Semiconductor memory, PD, SD Card, etc.

Unit of Memory :

Bit- Binary digit (0,1)

4 Bit                                    =       1 Nibble

8 Bit                                    =        1 Byte

1024 Byte                           =        1 Kilo Byte

1024 KB                             =        1 Mega Byte

1024 MB                             =        1 Giga Byte

1024 GB                             =        1 Tara Byte

1024 TB                              =        1 Peta Byte

1024 PB                              =        1 Exa Byte

1024 EB                              =        1 Zeta Byte

1024 ZB                              =        1 Yotta Byte

1024 YB                              =        1 Bronto Byte

1024 Bronto Byte               =        1 Geop Byte

1024 Geop Byte                 =        1 Sagan Byte

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Debit and Credit Rules, Cash and Credit Transaction Finding Rules.

Golden Rules of Debit and Credit

Personal Account:

             Debit : The Receiver

             Credit : The Giver

Real Account:

               Debit : What comes in

             Credit : What goes out

Nominal Account:

               Debit : All Expenses and Losses

             Credit : All Income and Gains

Cash and Credit Transactions Finding Rules:

Sometimes transactions are worded in such a way that it becomes difficult to decide whether they are cash or credit transactions. The following rules will make the position clear:1. A transaction is regard as a cash transaction if:2. A transaction is regarded as a credit transaction if:(a) The word "cash" is mentioned in the transaction. For example Bought goods for cash Rs. 5000 from A.(b) The name of the seller or buyer is not mentioned in the transaction. For example, Bought goods Rs. 5000.(a). The words "on credit" or "on account" are mentioned in the transaction. For example, Bought goods worth Rs. 5000 on credit.(b). The name of the seller or buyer is mentioned in the transaction and the word "Cash" is not mentioned. For example, Bought goods from A worth Rs. 5000.Every business transaction brings a double change in the financial position of the business. It brings a change in the assets, liabilities, owner's equity, expenses or revenues of a business.

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Fundamental of Computer Theories

1.What is a computer?

Ans: A computer is a High Speed Digital electronic device that operates under the control of instructions  and it has the ability to store, retrieve, and process data. It is a collection of two components Hardware and Software.

Classification of Computer

Classification based on Purpose:

1. General Purpose Computer

2. Special Purpose Computer

Classification based on Type:

1. Analog Computer :

Analog Computers are used mostly in Medical Sciences. This very kind of Computers work on Continuous data values, for eg. if you have to calculate the pressure or something similar then kind of technology having will be useful.

2. Digital Computer :

Digital Computers are the most commonly used computer on a digital technique which is widely used and preferred now-a-days. This kind of computers uses micro processor technology which is quite digital and able to calculate and execute million of instruction within a second. This also comes under kind of categories as we can see downwards..

3. Hybrid Computer :

The kind of computer comes with both characteristics (digital and analog) are called hybrid. This is used there where it needs to calculate both the digital and analog data for e.g. In Hospitals.

Classification based on Size:

1. Micro Computer (Personal Computer) : 

The processor is very small so that called Micro processor and device is called Micro Computer. Micro Computer is single user device example: Desktop, Laptom, Palmtop, Notebook, PDA, etc.

2. Mini computer :

The processor of Mini Computer is small but larger than Micro processor. Mini Computer is multi user device generally used in designing company for commercial use.

3. Main frame Computer :

It has larger processor and multiuser device. Number of users is more than Mini Computer. This is multiuser and multitasking device mostly used in Metrology.

4. Super Computer:

The processor is biggest than other Computer and processing capacity is highest than other devices. It is multi user fastest calculating device, generally used in nuclear science for calculation purpose. CRAY-I is the first Super Computer. India's First Super Computer is PARAM-10000

4.Some Advantages of a Computer :      

ANS :-1. Very high speeds

           2. Large storage and retrieval Capacity

           3. Accuracy in calculation         

           4. Versatility(Multiple Task/ Multitasking/ Multiple Work) 

           5. Diligency

5. Some Disadvantages of a Computer :

ANS :-1. Cannot think                

           2. Cannot learn by experience 

        3.Cannot take independent decision.Requires human instruction to take a decision.

6. What is Software ?

ANS : Software is the series of instructions that tells the hardware how to perform tasks. Without software, Hardware is useless. Hardware needs the instructions provided by Software to start work.

7. Software two type :

ANS : 1. System Software

            2. Application Software

8. What is Hardware ?

ANS : The electric electronic and mechanical equipment that makes up a computer is called hardware. Hardware is any part of a computer you can touch and feel any peripheral equipment such as Keyboard, Printer, Monitor, Speakers and Mouse devices.

9. What is input device?

Ans: Data entered into a Computer is called input devices.

Some examples of input devices are :   

1.Keyboard 2.Mouse 3. Joysticks  4. Touch Screen 5. Digital Camera 7.

Video conferencing 8.Voice input 9. Audio input.

10. What is output device?

Ans: Computer is fed with a lot of data to be processed and organised. The data that has been processed in to a useful form is called output devices.

Some example of output  devices are :

1. Monitor 2. Video Card 3. Printers 4. Speakers.

11. Mention the name of four early computer .

ANS:-1.Mark I 2.ENSIC  -Electronic Numeric Integrator and Calculator 3.EDVAC –Electronic Discrete Variable Automatic Compurer  4.UNIVAC –Universal Automatic Computer.

12. Any  computer system can broadly  classified in terms of  four component dimensions:

*Hardware

*Operating system

*Application programs (like ms word, Games,Calculator)

*User (people who work on the computer)

13. Generation of Computer

First Generation

First generation computers,starting with the UNIVAC I in 1951, used vacuum tubes and their memories were made of thin tubes of liquid mercury and magnetic drums.

Second Generation

Second general systems in the late 1950 s replaced tubes with transistors and used magnetic cores for memories (IBM 1401,Honeywell 800).size  was reduced and reliability was significantly improved…….

Third Generation

Third generation computers, beginning in the mid 1960s, used the first integrated circuits(IBM 360,CDC 6400) and the first operating systems.online systems were widely developed,although   most processing was still batch oriented, using punched cards and magnetic tapes.

Four Generation

The fourth generation which start in the mid 1970s, brought us computers made entirely of     chips.It spawned the microprocessor and personal computer.It introduced distributed processing and office automation.For the first  time,query languages,report writers and spreadsheets put large number of people  in touch  with the computer.

Fifth Generation

Fifth generation computer are expected to combine very large  scale integration (VLSI)with sophistication approaches to computing, including artificial intelligence and true distributed processing.

Windows XP

Microsoft windows XP is an operating system program that controls the overall activity and ensures that all parts of your computer work together smoothly and efficiently of your computer.

Basic components of Windows

1. My Computer:The my computer icon,on a windows desktop includes the disk drives and system folders,which the control panels and dial-up networking.

2. My  Documents:It provides a convenient place to store your documents.

3. Recycle Bin:In windows,an icon of a waste can used for deleting files .It stores deleted files and allows you to recover them later.

4. My network place:It allows you to view the folders and files available on your network.

5. Desktop:It is a background area of your screen.
                                                   

6. Start Button:It provides quick access to programs and files.

7. Quick Launch toolbar:Provides quick access to commonly used features.

8. Clock:Displays the current time.

10. Windows:A Windows is a rectangular area on screen surrounded by a window frame with a title at the top.When you launch a windows application.It is displayed in its own window.Each subsequent application is displayed in another.

11. Scrollbar: A horizontal or vertical scrollbar that contains a box  that looks like on elevator in a shaft.The bar is clicked to scroll the screen in the corresponding displayed in another.

12. Title bar: Displays the name of an open windows.

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