on the basis of brand

 On the basis of brand we have mainly three computers as given below.

1.)IBM computers

2.)IBM compatible

3)Apple/Macintosh

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Let's know in  detail.

1.)IBM computers

        Features:

        Features:

1. powerful computer developed by IBM

2. uses XT technology

3. uses 8088 intel microprocessor running at 4.77 MHZ

4. had extra co-math processor

5. had memory 128KB,10MB hard disk 

6. had five 8-bit input/output channel slot.

7. supported BASICA language for programming

8. could be used for small business ,home use.

 Now-a-days, IBM computers are replaced by many new features:

1. IPS ( In-plain Display )display

2. I7 processor (2.6 GHZ)

3. NVIDIA graphics

4. 64GB memory with 1TB hard disk/SSD

5. Light weight

6. Thunderbolt support

7. Spill proof/resistant

8. Supports latest USB port

.      Examples: IBM 604, PC/XT, IBM Portable PC, etc.

2.)IBM compatible

     Features:

        

1. this is same computer as of that IBM computer. It can run all softwares as those.

2. they are low cost computers with same architecture of IBM original PC

3. used operating system ‘DOS’.

4. used firmware based BIOS

5. used BASIC programming language developed by Microsoft

6. had 8088 processor

7. used 20-bit memory space

8. used video card

9.  Spreadsheets, WYSIWYG word processors, presentation software and remote communication software. But this capability was beyond the what ‘DOS’ provided.

and many other features of original IBM computer

Computers developed by companies HP, Dell etc.,

3)Apple/Macintosh

     Features:

   

1. develops personal computer as a brand

2. a first computer which used GUI concept with Mouse

3. has different architecture than other machine

4. its first design had 64 KB to 128 KB RAM, 6809E processor

5. had 64kb of ROM with BIOS

6. had limited color display with limited resolution

7. used PASCAL and later C++ like languages for development

8. 16/32 bits operating system

9. supports multitasking,multiprogramming,real time,time sharing

10. used ‘snow white  design language’ for the computer design and look

11. owes own hardware, softwares, architectures.

12. expensive systems

Now-a-days, apple computers come with following features:

1. Retina display

2. Ultraportable

3. Primary Memory 16 GB with SSD and secondary upto 1TB (SSD or Hard disk)

4. I5 processor

5. Large screen

6. Intel graphics

7. USB

8. Multi-touch trackpad

9. Thunderbolt (40GB/s)

10. First aid button

11. Keychain (for password)

12. Secured (unix based)

13. Finger print etc

on the basis of size

 We have four computers on the basis of size.

1.Super computers

2.Mainframe computers

3.Mini computers

4.Micro computers

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Let's know in detail.

1.Super computers:

        Features:

                    

1.  A supercomputer is a computer that is at the frontline of current processing capacity, particularly speed of calculation.

2.  Most powerful, fastest, and also very expensive.

3. performance is measured in FLOPS(FLoating-point Operations Per Second)

4.  Can perform more than 1 trillion calculations per second.

5.  Parallel processing is done in this computer. It may use symmetric or Massive parallel processing

6. uses powerful operating system (LINUX) with lightweight kernel. 

7. Supercomputers of the 21st century can use over 100,000 processors.

8. Supports more number of terminals at same time (more than 1000)

9. while working they may share memory or operating system or bus with processor.

10. A number of RISC (Reduced Instruction Set Computer) processor are used in supercomputer and its world length is 64 or more bit.

11.  use of supercomputers include animated graphics, fluid dynamic calculations, nuclear energy research, and petroleum exploration.

12. advanced inputs, outputs,secondary storage with primary.

100’s of GB of RAM, 1000’s of GB of secondary storage

   Examples: CRAY X-MP/24, NEC-500, PARAM, Fujitsu VP-2600/10,ANURAG.

2.Mainframe computers

        Features:

            

1. Mainframes are designed to handle very high volume of data. it can be said one housed CPU.

2. Less powerful,smaller in size and less expensive than supercomputer.

3. resulting in high reliability and security

4. measured in millions of instructions per second (MIPS)

5. word length was 32-bit or more.

6.  more number of input-output facilities with the ability to offload to separate engines.

7. supports virtualization (runs many instances in virtual environment without using physical devices)

8. supports hot swapping.

9.  supporting hundreds, or even thousands, of users/processors simultaneously.

10. supports fault tolerant .

11. mostly used for transaction processing

       Examples: z900, z990, System z9, and System z10, etc

3.Mini computers:

    Features:

            

1. It is a general purpose machine with a smaller CPU than a mainframe and super

2. It can be used as midrange servers.

3. Its word lengths are usually 16 to 32 bits.

4. It has a transfer rate of about 4 million bytes/second.

5. It supports multi-tasking,multi-programming concept

6. It had 4-bits bus system called bit-slice architecture

7. It can support all high level languages.

8. It can support between 15 to 25/50 terminals.

9. The CPU speed is 100 kips to 500 MIPS (Million Instructions per second).

10.  The main memory size ranges from 256kb to 32Mb.

Examples: MAI Basic4, DEC PDP and VAX Series, Prime Computer Prime 50, Data General Nova, Wang Laboratories 2200 and VS Series, etc.

4.Micro computers:

        Features:-

            

1. mallest and cheapest computer compared to super or mainframe or mini.

2. it is general purpose machine and does not need dedicated room.

3. contains only one microprocessor so called microcomputer.

4. supports 16/32/64 bits system.

5. used with CUI/GUI operating system.

6. used inputs like keyboard,mouse with monitor.

7. used RAM as primary memory (256Kb or more) and magnetic disk/optical disk as secondary.

8. does not support more no. of terminals.

9. its microprocessor speed is from MHZ to GHZ.

10. used for small business,accounting, for home and word related problems

11. . used intel chip like 8008

12. supports multiprogramming, multitasking, real time processing etc.

13. it has many types like, PDA,LAPTOP,TABLET ETC

         Examples of such computers are PS 386, PS 486, PENTIUM (P - I, II, III, IV), IBM PC, PC-AT, etc.

on the basis of working principle

 We have following computers on the basis of working principle/mechanism.

1)Analog computers

2)digital computers

3)Hybrid computers

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Let's know in detail.

1)Analog computers:-

                         An analog computer is a form of computer that uses the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities symbolically, as their numerical values change.

       Features:      

1. uses variable like pressure,temperature etc whose values vary continuously.

2. uses sine wave.

3. It records waveforms as they are.

4. may subject to deterioration of wave by noise.

5. more likely have low accuracy

6. hardware is not so flexible

7. best suited for audio and video transmission

8. consumes less bandwidth

9. error prone

e.g. Plesley,speedometer etc

2)digital computers:-

                    Digital computer is a computer which stores data in terms of digital numbers and proceeds in discrete steps from one state to another.

        Features:-

            

1. does not use variable concept; rather uses discrete values to represent information.

2. uses square wave (for max and min voltage)

3. waveforms are converted into numbers to record information.

4.  without deterioration during transmission 

5. high level of accuracy

6. Digital hardware is flexible

7. for any type of computing

8. consumes more bandwidth

9. mostly free from errors

                                                                picture source:theintactone.com

3)Hybrid computers:-

                    Hybrid computers are computers that exhibit features of analog computers and digital computers. The digital component normally serves as the controller and provides logical operations, while the analog component normally serves as a solver of differential equations.

        Features:-

        
It is combination of qualities analog and digital computers.

2.  It can process both continuous and discrete data.

3.  It has capability to convert one type of data to another.

4.  It is the special purpose machine.

5.  It is mostly used in airplane, hospital, weather forecasting.

6.  It usually has high cost compared to analog and digital.

Examples: HRS 100, radar, XPC 100, GVS 100.

Types of computers

 We have different category of computers. All the computers are classified into following categories.

1.)On the basis of working principle/mechanism

2)On the basis of size

3)On the basis of brand

4) On the basis of model

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know about About mobile computing:

Fifth generation computers

 Features:-

• 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.

• Artificial Intelligence is the branch of computer science concerned with making computers behave like humans and we can say that this is the main component of fifth generation computers.

• The greatest advances have occurred in the field of games playing. In the area of robotics, computers are now widely used in assembly plants, but they are capable only of very limited tasks.

• The fifth generation of computers have the following features:

1. These computers will be fully parallel processing capacity.

2. Computers will be intelligent and knowledge based of AI.

3. The language of operating system will be PROLOG.

4. The language of AI in fifth generation computer has also enabled expert system.

5. Computers will use super conductor memory like bio-chips &Gallium Arsenide as memory device to increase its speed even further.

ARTIFICIAL INTELLIGENCE:

• It is the intelligence of machines and the branch of computer science that aims to create it.

• For variety of machines and computers various components are used.

• The purpose of artificial intelligence have uncountable uses and advantages such as in calculations, gaming, defense, etc.

• Followings are the features of artificial intelligence:

1. it can perform many tasks itself,

2. It can be a great help in medical science,

3. It can be very useful in defense system,

4. It may have problem to find things know objects, differentiate between them, etc. in the case of robots,

5. It can perform tasks without stopping, etc.

6. 
   

summarized features:

Fifth Generation Computers (Present & Beyond)

1. ULSI technology 

2.  Development of true artificial intelligence

3.   Development of Natural language processing  

4. Advancement in Parallel Processing  

5. has capability to interpret just like human being. 

6. supports to make expert system to take decision in real time system.

7. More user friendly interfaces with multimedia features  

8. quantum computing using qubits (Quantum bits)(is exponentially faster than conventional computers).

9. more processors on same computer .

10. more storage capacity using semiconductor technology.

11. advancement in input and output devices.

12. uses high level languages like, java,.net 

e.g.   Desktop  Laptop  NoteBook  UltraBook,Clout