Introduction to Microcomputer

At first let me discuss about the definition of microcomputer:

Microcomputer is a computer which is processor level computer, containing memory, and input/output (I/O) facilities. It also contains microprocessor (a central processing unit on a microchip), memory in the form of read-only memory and random access memory, I/O ports and a bus or system of interconnecting wires, housed in a unit that is usually called a motherboard.
Early microcomputer also known as personal computer:

Flash Back
The KIM-1 Microcomputer:

KIM-1 is for Keyboard Input Monitor, was developed by MOS technology in 1976. It was a single board circuit board in which, components were placed. Processor was 6502 made by MOS. It have memory storage, ram, keyboard, and output display, input pins etc.
This earlier machine provide hexadecimal calculation. As we see, it contain 23 keys, which are 1- F (Hexadecimal) and others function. It needs 5 volt power supply. This computer can be program by programming card provided by KIM-1. 6502 processor was the base of the today’s computer. Apple2 series was also based on this processor model. 

KIM-1 Details :

Today’s microcomputer

There are four basic parts to a computer:
Input / Output, ALU, CU and Memory
I/O can be broken down to Input devices and Output devices
Input Devices include: keyboards, joysticks, mice, light pens, touch-sensitive screens, scanners, graphics tablets, speech-recognition devices, and vision systems.
Output Devices include: Any device for displaying, in a form intelligible to the user, the results of processing carried out by a computer.  This can include monitors, printers, LEDs, traffic lights, motors and many other devices.                                                                                                                        
The Arithmetic Logic Unit.  In a computer, the part of the central processing unit (CPU) that performs the basic arithmetic and logic operations on data.
The Control Unit is the part of the central processing unit that decodes, synchronizes, and executes program instructions. Memory is like a page in a workbook it is where everything happens. Other than the CPU is probably the most important part of your computer.
Inside the computer in today’s computers there are 7 basic components they are:
     The Motherboard
     The CPU
     The Power Supply
     The Video board
     The Hard Disk
Drive Internal components slot of modern microcomputer:

Now-a-day’s computer is getting complex and it can do many task. The component or device is increasing day by day.
We are using multi-processor, RAM, ROM, cache memory, buses motherboard etc. as I/O device, monitors, keyboards and other devices for input and output may be integrated or separate. Computer memory in the form of RAM, and at least one other less volatile, memory storage device are usually combined with the CPU on a system bus in one unit. Other devices that make up a complete microcomputer system include batteries, a power supply unit, a keyboard and various input/output devices used to convey information to and from a human operator. Motherboard contains all the components of a Microcomputer. Microcomputers are designed to serve only one user at a time, although they can often be modified with software or hardware to concurrently serve more than one user. Microcomputers fit well on or under desks or tables, so that they are within easy access of users. Bigger computers like minicomputers, mainframes, and supercomputers take up large cabinets or even dedicated rooms.
Sample component set of a complete microcomputer:
DELL Optiplex 7020MT - Core i5

Optiplex  7020 Mini Tower
Country of Origin
Processor Speed
Intel®  4th  Generation Core™ i5-7020 (3.20 GHz,4 cores, 4 threads)
Cache Memory
6MB L3 Cache
Intel® Q87 Express Chipset
4GB (1x4GB) DDR3 1600MHz SDRAM Memory expandable up to 16GB, 4 DIMM slots; Non-ECC dual-channel
Hard Drive
500GB 7200 rpm Serial ATA
Intel HD Graphics  4600
Optical Drive
16x DVD+/-RW Drive
Integrated Intel® 1217LM Ethernet LAN 10/100/1000
Internal Dell Business audio speaker
Total 10 USB Ports:
4 External USB 3.0 ports (2 front, 2 rear) and 6 External USB 2.0 ports (2 front, 4 rear)
1 RJ-45
1 Serial;
2 Display Port
2 PS/2
2 Line-in (stereo/microphone), 2 Line-out
Number of Bays
2 internal 3.5”
2 external 5.25”
Expansion Slots
1 full height PCIe x16
1 full height PCIe x16 (wired x 4)
1 full height PCIe x1
1 full height PCI
DELL 18.5" Monitor
Dell USB Business Keyboard
Dell USB Optical Mouse
Power supply Unit
Standard 265W PSU Active PFC Mini Tower (MT)
Operating System
Free DOS/Genuine Microsoft windows 7 professional with license
Normally brand pc is little bit costly, because there hardware is comfortable with each other. So the component live long times and give better service. Again, clone pc is cheap but the hardware are from different brand. So they can’t perform better than brand pc.