Fourth generation of computer
The fourth generation of computer were developed during 1974-till.They used micro chips having about -50,000 transistors on a chip as a major component.
A micro chip is a single chip that consists of the entire computer circuiting American intel corporation develop the first microprocessor called 4004 in 1971.The main features of this generation of computer are:
-Highly reduce the size of computer.
-The operating speed increase beyond HIPS(million Instruction Per second)
-Magnetic & optical storage devices with capacity more than 360 GB.
-Mltiprocessing & multiprogramming operating system are used.
-4G(Fourth generation) languages are used eg:Ctt,Java,Net e.t.c.
-Eg:8086,8088,80286,80386,80486,80586,(Pentium-I,II,III,IV) e.t.c.

Fifth generation of computer
The development of fifth generation of computer is being started but not completed til now.These computer will use Bio chips which are made from Gallium & Arsenite as major component.Japan has been working to develop such computer using the concept of A.I.
(Artificial Intelligence)
Features of fifth generation of computer
-Able to understand human language & speak ,think & make decision.
-Can perform large number of parallel processing.
-Speed is extremely high.


Classification of computer
1) On the basis of work.
a. Analog computer
It work on the supply of continious electrical pulse.The display of output is also continious.It has a very limited memory.It can perform a limited type of calculation.It is used for only scientific research & engineering purpose.eg:automobile ,speedometer ,clock with a two hand & slide rule.

b. Digital computer
It dosen’t work on the supply of continious electrical pulses.It has a very big memory.Generally ,we use digital computer in our daily lifea.It is used not only for scientific research & engeneering purpose but also in industries ,government sector ,education ,medicine ,law ,social services e.t.c. a digital computer is one that directly counts numbers or digits that presents numbers ,letters or other special symbols.eg:digital clock ,present computer.


c. Hybrid computer
The computer that processes the features of both analog as well as digital is called hybrid computer.These are used on intensive care unit of hospitals ,jet planes & other data analysis terminals.It is very useful & confidend in scientific research ,medicine & engineering purposes.


#Difference between Analog & Digital computer
1) Analog computer
#It is costly.
#It is used in scientficial ,medical & industrial field.
#It is specific slow & less accurate.

2) Digital computer
# It is less costly.
# It is used for statical data numerical problem &
Science
#It is versatile ,fast & accurate.


1) On the basis of size
a. Super
It is the largest computer of very high efficiency & storing capacity having feature of multi user of multi processer.It be able to solve very difficult & complex problems within a nanosecond.It use RISC processor.(Reduced Instructor Set Computer)
It is used in the following:
1) Used in forecasting weather & climate.
2) Used in millitary research & defense system.
3) Used in encrypting decoding sensitive intelligence information.
4) Used in automobile aircraft & spacecraftdesigning.
5) Used in seismography plasma & nuclear research.
6) Study of DNA structure & gene engeneering.
7) Digital film rendering.
8) In metrology
Eg:PAEAM ,services developed by C-DAC ANURAG ,CRAY-I ,CYBER 205 e.t.c.


b. Mainframe computer
It is very powerful muti-user ,general purpose computer system & supports wide range of input & ontput terminals with large backing storage capacity.It supports large number of terminals upto 100 or more.It works on the hime saving basis.the first mainframe compater dereloped by ibm was system 360.

Applications:
-Credit card procession.
-Bank account management.
-Business data processing.
-Air traffie coutem & induslrial design.
Eg:system1360 ,IBM 51390 ,IBM 51709 e.t.c.

3) Mini computer
Mini computer is also known as mid-range comouters & more powerful & larger than micro computer.It is also multiuse computer & supports more then dozens of people at a time.
Applications:
-Used in universities.
-Used in large business.
-Used in scientific research instrumentation
System ,industial process.
-Used in monitering & controlling system eg PDP-II (Program Data Processor)

2) Micro computer
It is also called home PC or desktop PC because it is a single user computer.it supports many high level languages ,multimedia graphics ,3D-graphics & games.It is popular among students ,professionals due to small size ,low price & low maintainance cost.

Application:
- For different programming ,graphic designing &
desktop publishing.
- For listening multimedia songs e.t.c.

Types of micro computer
i)Laptop
ii)Palmtop
Types of micro computer
i) Laptop
ii) Palmtop
iii) Multimedia
iv) PDA (Personal Digital Assistant)



i) Laptop/Palmtop
These are small ,portable ,less power consuming & equipped with all the facilities of modern PC.These computers can be operated by battery.These computers have as equal as storing capacity like desktop & all facilities are included.It has CD-Drive ,FLOPPY DRIVE ,COMBO & other input output parts.

The idea of laptop computers was started by Alien kay of Xerox palo alto research centre in 1970 & named to notebook but the first laptop was designed by William Moggrage of grid system in 1979.Palmtop computers are very useful for remote areas where there is no electricity. Facility available.
The higher authorities ,social working in remote areas.They get more benefit by palmtop as well as laptop.
Simply the desktop is your personal computer seated at the top of your disk laptop as no problem on your lap & palmtop on your palm.


ii)Multimedia computer
Multimedia is a combined form of two or more media like as text ,graphic ,sound & animation e.t.c. ADC (Analog Digital Computer) converts he sound wave into digital signal in multimedia computer MPEG (Motion Picture Expert Group) is a standered use to compress sound (audio) & videos for computer name HPEG-1 ,MPEG-2 e.t.c.


iii) PDA
PDA is a small sized portable hand-held electronic edvice which has all the features of PCs.It has input processing storage & output capability like the other micro computer.We can transfer data from PDA to PC & PC to PDA.It is used for daires calendar ,address ,book e.t.c.