Fundamental of Computer

COMPUTER  BASIC COURSE 

(From Beginner to Advance Level)

1- Fundamental of Computer :--

What is Computer ?

In Greek word, computer means Calculations

Computer is an electronic device which store data information and after processing is gives us a meaning full results. 

Or

Every device is a computer that is electronic, takes some input, then processes and gives output..

Block Diagram of Computer

Full Form of Computer

C -- COMMON

O -- OPERATING

M -- MACHINE

P -- PURPOSELY

U -- USER

T -- TRAINING

E -- EDUCATION

R -- RESEARCH

Note:-- This full may varies but if you write this full form still got full marks.

Different between CPU and Cabinet ?

CPU

Microprocessor(CPU)

Full form of CPU is Central Processing Unit and its also called Microprocessor Chip and Brain of computer which performing ALU (Arithmatic Logical Unit) operation and communicate with other device to connect it.The microprocessor follows a sequence: Fetch, Decode and Execute.

Block diagram of CPU

CABINET

Computer case is also known as Computer cabinet in which all component of computer fitted like motherboard, CPU, RAM, HDD etc. But when we attach all these parts to the cabinet, it is also called as CPU.

Cabinet

What is Hardware ?

Hardware is a comprehensive term for all of the physical parts of a computer, as distinguished from the data it contains or operates on, and the software that provides instructions for the hardware to accomplish tasks.

Hardware is anything which tangible

What is Software ?

Software is collection of instruction or data that tell computer how to work or perform following task.

There are two types of Software:--

System Software -- It is used to operate computer hardware.

Application Software -- It is used by user to perform specific tasks.It's cannot run without presence                                            of  system software.

Operation System 

It is system software 

Examples are DOS, windows XP, windows Vista, windows 7, windows 8, Solaris, Macintosh, Linux,

Ubuntu etc

It provides interface between user and machine 

Acts as a manager of the computer system

It does process management, memory management, file management.

Sr. No.	Multiprocessing	Multiprogramming
1	Multiprocessing refers to processing of multiple processes at same time by multiple CPUs.	Multiprogramming keeps several programs in main memory at the same time and execute them concurrently utilizing single CPU.
2	It utilizes multiple CPUs.	It utilizes single CPU.
3	It permits parallel processing.	Context switching takes place.
4	Less time taken to process the jobs.	More Time taken to process the jobs.
5	It facilitates much efficient utilization of devices of the computer system.	Less efficient than multiprocessing.
6	Usually more expensive.	Such systems are less expensive.

               

  Difference Between Cache and Register

 is that Memory cache helps speed the processes of the computer because it stores frequently used instructions and data. While registers are also a part of a computer processor and holding one small piece of data in Processor. A register may hold a piece of data, like a storage address and computer instruction.

CACHE

Most of today’s computers improve processing times with cache (pronounced cash). Two types of cache are memory cache and disk cache. Memory cache helps speed the processes of the computer because it stores frequently used instructions and data. Most personal computers today have at least two types of memory cache: L1 cache and L2 cache.

REGISTER

Downlink and uplink

The communication going from a satellite to ground is called downlink, and when it is going from ground to a satellite it is called uplink. When an uplink is being received by the spacecraft at the same time a downlink is being received by Earth, the communication is called two-way. If there is only an uplink happening, this communication is called upload. If there is only a downlink happening, the communication is called one-way.

DS1 has a constant downlink going to Earth sending little bits of information. However, most of the communication is done two-way with the Deep Space Network.

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Registers are also a part of a computer processor and holding one small piece of data in Processor. A register may hold a piece of data, like a storage address and computer instruction. Some instructions specify registers as part of the instruction. E.g it may be specified that an instruction of two registers can be placed together on a specified register. There must be a large register enough so that it can hold instructions. For example, in a 32-Bit instruction computer, a register must be 32 bits in length. But in many computers, there are smaller registers like half registers for shorter instructions. Registers may have arbitrary or numbers names which depends on the processor designs and language rules.

S.No.	System Software	Application Software
1.	System software is used for operating computer hardware.	Application software is used by user to perform specific task.
2.	System softwares are installed on the computer when operating system is installed.	Application softwares are installed according to user’s requirements.
3.	In general, the user does not interact with system software because it works in the background.	In general, the user interacts with application sofwares.
4.	System software can run independently. It provides platform for running application softwares.	Application software can’t run independently. They can’t run without the presence of system software.
5.	Some examples of system softwares are compiler, assembler,   debugger, driver, etc.	Some examples of application softwares are word processor, web browser, media player, etc.

Primary Key	Foreign key
Primary key uniquely identify a record in the table.	Foreign key is a field in the table that is primary key in another table.
Primary key can’t accept null values.	Foreign key can accept multiple null value.
By default, Primary key is clustered index and data in the database table is physically organized in the Sequence of clustered index.	Foreign key  do not automatically create an index, Clustered or non-clustered. You can manually create an index on foreign key.
We can have only one Primary key in a table.	We can have more than one foreign key in a table.

	MICR	OCR
1	Known as magnetic ink character Recognition.	Known as optical character reader
2	This scanner can read the characters Printed with magnetic ink.	These scanner can read the standard printed character Printed with normal ink
3	It uses principal of magnetism for Reading characters.	It uses principal of optics (light) for reading Characters.
4	It is mainly used in banking industry for Reading and decoding of cheques / Drafts efficiently and securely.	Used for efficient reading of high volume of printed Data like letters, news paper materials etc.

Impact printer / Dot-matrix Printer	Non impact Printer / Laser  Printer
1. It prints characters or images by striking print hammer or wheel against an inked ribbon.	1. It prints characters and images without striking the papers.
2. Its speed is slower.	2. Its speed is faster.
3. Its printing quality is lower.	3. Its printing quality is higher.
4. It normally uses continuous paper sheet.	4. Its normally uses individual paper sheet.
5. It generates noise during printing.	5. It does not generate noise during printing.
6. It uses inked ribbon for printing.	6. It uses toner or cartridge for painting.
7. It is less expensive.	7. It is more expensive.
8. Dot matrix is an impact printer.	8. Laser printer is a non-impact printer.

RAM vs ROM difference	RAM	ROM
Data	The data is not permanent and it can be altered any number of times.	The data is permanent. It can be altered but only a limited number of times that too at slow speed.
Speed	It is a high-speed memory.	It is much slower than the RAM.
CPU Interaction	The CPU can access the data stored on it.	The CPU can not access the data stored on it. In order to do so, the data is first copied to the RAM.
Size and Capacity	Large size with higher capacity.	Small size with less capacity.
Usage	Primary memory (DRAM DIMM modules), CPU Cache (SRAM).	Firmware like BIOS or UEFI. RFID tags, microcontrollers, medical devices, and at places where a small and permanent memory solution is required.
Cost	It doesn’t come cheap.	Way cheaper than RAM.

SPAM

Also known as unsolicited bulk e-mail messages or any email messages irrespective of content that is unwanted or unrequested by the recipient. Spam messages are mostly commercial advertising, although chain letters, political mailings and other forms of non-commercial mailings are often included under the same categorization. A large portion of spam has also been found to be comprised of ads for products of dubious quality and services of questionable legality.

There are two types of spam: intentional and unintentional.

Intentional spam comes from spammers who are soliciting products or attempting to commit fraud.

Unintentional spam originates from computers that are infected with a virus or worm that activates e-mail distribution processes in the background. The virus or worm attempts to send bulk messages from the infected computer without the awareness of the computer owner.

	VIRUS	MALWARE
Definition	A virus is a program code that attaches itself to a program or file and infects other computers through that file.	Malware is short for malicious software. These are programs used to disrupt computer  operations, gather sensitive data or gain access to private systems.
Controlled remotely	No	Depends on the type of Malware.
Types	Resident viruses and non-resident viruses.	Computer viruses, Ransomware, Worms, Trojan horses, Rootkits, Keyloggers, Dialers, Spyware, Adware, Malicious  BHOs, Rogue security software
Process of infection	Attaches itself to an executable file, folder or program.	Can spread automatically or requires  user  intervention, depending on the  type  of malware.
Process of spreading	Viruses rely on transfer of files or other programs in order to spread to other systems.	Spread using executable software of through transference of files and folders.
Infecting files	Yes, it modifies, alters or deletes certain files.	Can modify, alter or delete data. Can  collect information and pass on other  locations.
Speed of spreading	Slower compared to worms.	Speed depends on the type of malware.  Viruses are slow in spreading,  while worms are fast.
Type	Malware	Malware
Replication	Yes	Yes
Protection	Antivirus software	Antimalware software
Removal	Antivirus, formatting, system restore.	Antimalware, formatting, system restore.

HIGH LANGUAGE VS LOW LEVEL LANGUAGE---

High Level Languages

High level languages are written in a form that is close to our human language, enabling to programmer to just focus on the problem being solved.

No particular knowledge of the hardware is needed as high level languages create programs that are portable and not tied to a particular computer or microchip.

These programmer friendly languages are called ‘high level’ as they are far removed from the machine code instructions understood by the computer.

Examples include: C++, Java, Pascal, Python, Visual Basic.

Advantages

• Easier to modify as it uses English like statements
• Easier/faster to write code as it uses English like statements
• Easier to debug during development due to English like statements
• Portable code – not designed to run on just one type of machine

Low Level Languages

Low level languages are used to write programs that relate to the specific architecture and hardware of a particular type of computer.They are closer to the native language of a computer (binary), making them harder for programmers to understand.

Low level refers to:

• Assembly Language
• Machine Code

Assembly Language

Few programmers write programs in low level assembly language, but it is still used for developing code for specialist hardware, such as device drivers.It is easy distinguishable from a high level language as it contains few recognisable human words but plenty of mnemonic code.

Advantages

• Can make use of special hardware or special machine-dependent instructions (e.g. on the specific chip)
• Translated program requires less memory
• Write code that can be executed faster
• Total control over the code
• Can work directly on memory locations

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