Digital Counter

A Digital Counter is obtained by arranging the flip-flops. These are the applications of flip-flops. Other than counting, these are used for measuring the frequency as well as time. These are used to increase the addresses in memory. The operation of these devices depends on the single clock applied.  These are made of flip-fops as basic elements. There are two states included in the flip-flops. The high state is represented by 1 and the low state by 0. The operation of the counter can be made possible by high state-driven flip-flops. Counters consist of modes that are represented by the number of countable states, for example a mod-8 counter. In this, the number of states countable is from 000 to 111 (that is 0 to 7). Hence eight countable states name the counter as a mod-8 counter.

What is Digital Counter?

Definition: The circuit is designed with digital logic to obtain information about the number of events that occurred. This type of digital logic device can be defined as a Counter. The design of counters can be achieved by following various steps.

1. The number of Flip-Flops based on the requirement.
2. Accordingly, the State diagrams/ Excitation Tables are drawn.
3. Further, the expressions are minimized using various techniques.
4. Finally, the logic diagram is designed.

The above steps are especially followed fro the design of the type of counter known as Synchronous Counters.

Types of Digital Counters

The interconnection of the flip-flops results in the classification of the counters.  Although the single clock signal applied to the counters. There is a difference among the operation based on a single cock applied to the flip-flops in the circuit or the signal applied to the main flip-flop.

The types of counters are:

1. Asynchronous Counters
2. Synchronous Counters

The asynchronous counters are also referred to as Ripple counters. The simplest in design among the other counters is the ripple counter. The least quantity of hardware is required for this counter. The flip of one stage reflects the flip in another stage in asynchronous counters. These counters are further described as ‘Serial Counters’.

But in the other type of counter called synchronous counters, each flip-flop in the circuit gets triggered with the same clock at the same time. This is possible by connecting each flip-flop clock line with a single clock. The operation occurred in such types of circuits will be in coordination or synchronization with all the flip-flops present.  Hence these are referred to as Synchronous Counters.

Based on the clock signal applied the counters are classified as synchronous and asynchronous counters. In the Asynchronous type, only the first flip-flop is provided by the main cock. the remaining flip-flops are powered with the output obtained in the previous stage of flip-flops. There is another category of counters referred to as Decade Counters. This counter is able to count the pulses for ten values. The counting is done from 0 to 9.  Even this counting can be extended to 15 states.

What is the difference between Synchronous and Asynchronous Counters?

Based on the connections and the clock applied to the flip-flops there are certain differences between Synchronous and Asynchronous counters.  Some of the differences are listed as follows:

 

Asynchronous Counters	Synchronous Counters
1. In this counter, the main clock is applied to the first flip-flop. Whereas the other flip-flops are provided with the clock from the output of previous stage flip-flops.	1. The arrangement of the flip-flops in this counter is driven by the same clock.
2. The clock is not simultaneous for all the flip-flops in the circuit.	2. The clock is simultaneously provided for all the flip-fops.
3. To the more number of states, the design of this counter is simple to implement.	3. In this counter, as the number of states is increasing the design tends to become complex.
4. The propagation delay is more as the counters are not in sync.	4. The propagation delay will be less in comparison to the asynchronous counters because of the sync among the flip-flops.

In comparison to the asynchronous counters, the operation will be fast in synchronous counters. The frequency required for operation in the synchronous counters is high. In terms of cost, it is low in asynchronous counters.

Digital Counter Applications

These counter circuits are the basic ones in the ‘Digital Electronics’. These counters possess various applications.

1. In the conversions from Analog to Digital, these counters are used.
2.   In the applications of Timers for example Washings machines where we set the time. These counters are used.
3. With the help of these counters, a ‘Digital Triangular Wave Generator’ can be designed.
4. In the application of ‘Digital Clock’ counters are used.
5. A practical example of these devices is seen in the malls, stadiums, or the auditoriums. In the above situations to keep the data on the number of persons. This can be made possible or it will become simple because of these counters.

 

Digital registers

Introduction

A Flip-flop is a 1 bit memory cell which can be used for storing the digital data. To increase the storage capacity in terms of number of bits, you can use a group of flip-flops. Such a group of flip-flops is known as a Register. The n-bit register will consist of n number of flip-flop(s) and it is capable of storing an n-bit word.

The binary-data, in a register, can be transfered within itself from one flip-flop to another. A shift register is a type of register that allows such data transfers. Shift register has 4 modes of operations.

Shift Registers

A shift register is a piece of circuit that you will find inside a microprocessor. It is used to store and modify data. Now this is one of the simplest explanation I can give for a 2nd grade student.

But if you are some one who is studying about computers, this is just not sufficient. So I will have to explain it in a bit more detail. Alright? I will be getting a bit technical here. But it is how you will get a solid understanding of shift register. So you will have to bare it. Okay?

Sub-modules

The sub-modules of digital registers are:

1. Serial-in Serial-out
2. Serial-in Parallel-out
3. Parallel-in Serial-out
4. Parallel-in Parallel-out

Types Of Shift Registers

Based on the way the data is shifted, we have 5 different types of shift registers. They are:

• Left Shift Registers
• Right Shift Registers
• Bidirectional Shift Registers
• Circular Shift Registers &
• Linear Feedback Shift Registers

Now let explain what each of these registers work like:

Left Shift Registers

We have already talked about the left shift register. So I think you are familiar with it by now. If not, let me re-iterate. So in the case of a left shift register, the data is shifted to the left on each clock cycle.

Right Shift Registers

This is just like the left shift register. But here it is shifting the data to the right on each clock cycle.

Bidirectional Shift Registers

In the case of a bidirectional shift register, we can shift the data in both the directions. So you can shift the data either to it’s left or right!

Circular Shift Registers

In the case of a circular shift register, the last output is connected back as input. So your data will not be thrown out. Instead, will be shifted either left or right in a circular fashion!

Linear Feedback Shift Registers

In this type of shift register, the input of one flip flop will be linear output value of the previous flip flop.

Advantages & Disadvantages Of A Shift Register

It is now time to talk about the advantages & disadvantages of using a shift register. So what are they?

Advantages Of A Shift Register

• They are very fast to use.
• Very quick when you want to convert data from serial to parallel or vice versa. They are faster than normal serial to parallel converter circuits.
• They are very simple in design. So you can easily rig up a circuit to create a shift register.
• We can use them to encrypt or decrypt the data.
• We can use them to a delay signal.
• It is used in CDMA to generate Pseudo Noise Sequence Number.
• We can use them to track our data!

Disadvantages Of A Shift Register

While we could see that it has major advantages, shift register has one major disadvantage. That is:

• The strength of the output current coming from a shift register is not so strong.

 

 

 

 

Binary Arithmetic

Binary arithmetic is essential part of all the digital computers and many other digital system.

Binary Addition

Binary addition is the easiest of the processes to perform. As you'll see with the other operations below, it is essentially the same way you learnt to do addition of decimal numbers by hand (probably many years ago in your early school years). The process is actually easier with binary as we only have 2 digits to worry about, 0 and 1.

The process is that we line the two numbers up (one under the other), then, starting at the far right, add each column, recording the result and possible carry as we go.

Here are the possibilities:

• 0 + 0 = 0
• 1 + 0 = 1
• 1 + 1 = 2 which is 10 in binary which is 0 with a carry of 1
• 1 + 1 + 1 (carry) = 3 which is 11 in binary which is 1 with a carry of 1

The carry is involved whenever we have a result larger than 1 (which is the largest amount we may represent with a single binary digit).

Adding more than two numbers

It is possible to add more than 2 binary numbers in one go but it can soon get unweildly managing the carries. My suggestion is that you add the 1st and 2nd numbers together. Then take the result and add the third number to that. Then take the result and add the 4th etc. This way you may add as many binary numbers as you like and the complexity will never increase. It's a little more work but with practice you will get very quick at it.

Binary Multiplication

Binary multiplication is just about as easy as binary addition. Again it is the same process as we would do with decimal multiplication by hand. Again it is easier as binary only has 0 and 1.

We line the two numbers up (similar to addition). Then we multiply the entire top number by each individual digit of the bottom number. As we move across each digit we pad out the result with 0's to line it up. Finally we add all the results together.

Here are the possibilities:

• 0 * 0 = 0
• 1 * 0 = 0
• 1 * 1 = 1

As you have no doubt noticed, the process is fairly straight forward. If the binary digit on the second row we are multiplying by is a 1 then pad out accordingly and write out the top binary number. If the binary digit on the second row we are multiplying by is a 0 then we can just write out 0's.

Binary Subtraction

With binary subtraction we start to get a little more difficult (But not that difficult). Similar to binary addition, we will work through the numbers, column by column, starting on the far right. Instead of carrying forward however, we will borrow backwards (when necessary).

Here are the possibilities:

• 0 - 0 = 0
• 1 - 0 = 1
• 1 - 1 = 0
• 0 - 1 we can't do so we borrow 1 from the next column. This makes it 10 - 1 which is 1.

Another approach

The above example is the most convenient way for us to do binary subtraction by hand. There is another approach however and this is the way that computers subtract binary digits. This approach is called Two's Complement.

Let's say we want to compute 1000 ( 8 ) - 11 ( 3 ).

• Step 1: Write the equation out, padding the bottom number with 0's
  1000
  0011 -
• Step 2: Invert the digits of the lower number
  1000
  1100
• Step 3: Add 1 to the lower number
  1000
  1101
• Step 4: Add those two numbers together to get 10101
• Step 5: Remove the leading 1 (and any 0's after it). You are left with 101 ( 5 ).

Binary Division

Binary division is probably the most difficult of the binary equations. Fortunately, it is also made easier by the fact we only have to deal with 1's and 0's.

First off, some terminology. The number we are dividing by is the divisor. The number we are dividing into is the dividend.

The process is as follows:

• Step 1: Create the working portion of the dividend. Starting at the right, keep including digits until we have a number that the divisor will go into.
• Step 2: Work out how many times the divisor goes into the working portion (with binary this is easy as it will always be 1). Write this number above the line (in line with the far right digit of the working number).
• Step 3: Subtract the divisor from the working number. This becomes the beginning of the new working number.
• Step 4: Bring down digits from the dividend and add to the new working number until we have a new working number large enough for the divisor to go into.
• Step 5: Repeat steps 2 to 4 until we are at the end of the dividend.
• Step 6: The result of the final subtraction is the remainder.

 

Binary Codes

In the coding, when numbers, letters or words are represented by a specific group of symbols, it is said that the number, letter or word is being encoded. The group of symbols is called as a code. The digital data is represented, stored and transmitted as group of binary bits. This group is also called as binary code. The binary code is represented by the number as well as alphanumeric letter.

Advantages of Binary Code

Following is the list of advantages that binary code offers.

• Binary codes are suitable for the computer applications.

• Binary codes are suitable for the digital communications.

• Binary codes make the analysis and designing of digital circuits if we use the binary codes.

• Since only 0 & 1 are being used, implementation becomes easy.

Classification of binary codes

The codes are broadly categorized into following four categories.

• Weighted Codes
• Non-Weighted Codes
• Binary Coded Decimal Code
• Alphanumeric Codes
• Error Detecting Codes
• Error Correcting Codes

Weighted Codes

Weighted binary codes are those binary codes which obey the positional weight principle. Each position of the number represents a specific weight. Several systems of the codes are used to express the decimal digits 0 through 9. In these codes each decimal digit is represented by a group of four bits.

Non-Weighted Codes

In this type of binary codes, the positional weights are not assigned. The examples of non-weighted codes are Excess-3 code and Gray code.

Excess-3 code

The Excess-3 code is also called as XS-3 code. It is non-weighted code used to express decimal numbers. The Excess-3 code words are derived from the 8421 BCD code words adding (0011)₂ or (3)10 to each code word in 8421. The excess-3 codes are obtained as follows −

Gray Code

It is the non-weighted code and it is not arithmetic codes. That means there are no specific weights assigned to the bit position. It has a very special feature that, only one bit will change each time the decimal number is incremented as shown in fig. As only one bit changes at a time, the gray code is called as a unit distance code. The gray code is a cyclic code. Gray code cannot be used for arithmetic operation.

Application of Gray code

• Gray code is popularly used in the shaft position encoders.

• A shaft position encoder produces a code word which represents the angular position of the shaft.

Binary Coded Decimal (BCD) code

In this code each decimal digit is represented by a 4-bit binary number. BCD is a way to express each of the decimal digits with a binary code. In the BCD, with four bits we can represent sixteen numbers (0000 to 1111). But in BCD code only first ten of these are used (0000 to 1001). The remaining six code combinations i.e. 1010 to 1111 are invalid in BCD.

Advantages of BCD Codes

• It is very similar to decimal system.
• We need to remember binary equivalent of decimal numbers 0 to 9 only.

Disadvantages of BCD Codes

• The addition and subtraction of BCD have different rules.

• The BCD arithmetic is little more complicated.

• BCD needs more number of bits than binary to represent the decimal number. So BCD is less efficient than binary.

Alphanumeric codes

A binary digit or bit can represent only two symbols as it has only two states '0' or '1'. But this is not enough for communication between two computers because there we need many more symbols for communication. These symbols are required to represent 26 alphabets with capital and small letters, numbers from 0 to 9, punctuation marks and other symbols.

The alphanumeric codes are the codes that represent numbers and alphabetic characters. Mostly such codes also represent other characters such as symbol and various instructions necessary for conveying information. An alphanumeric code should at least represent 10 digits and 26 letters of alphabet i.e. total 36 items. The following three alphanumeric codes are very commonly used for the data representation.

• American Standard Code for Information Interchange (ASCII).
• Extended Binary Coded Decimal Interchange Code (EBCDIC).
• Five bit Baudot Code.

ASCII code is a 7-bit code whereas EBCDIC is an 8-bit code. ASCII code is more commonly used worldwide while EBCDIC is used primarily in large IBM computers.

Error Codes

There are binary code techniques available to detect and correct data during data transmission.

Error Code	Description
Error Detection and Error Correction	Error detection and correction code technique

Computer System Organization

A digital computer consists of an interconnected system of processors, memories, and input/output devices. Processors, memories, and input/output are key concepts and will be present at every level, so we will start to study computer architecture by looking at all three in turn.

PROCESSORS

The CPU (Central Processing Unit) is the ‘‘brain’’ of the computer.

A central processing unit (CPU) is the electronic circuitry within a computer that carries out the instructions  of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. The computer industry has used the term “central processing unit” at least since the early 1960s.Traditionally, the term “CPU” refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

The CPU is composed of several distinct parts. The control unit is responsible for fetching instructions from the main memory and determining their type. The arithmetic logic unit performs operations such as addition and Boolean AND needed to carry out the instructions.

The CPU also contains a small, high-speed memory used to store temporary results and certain control information. This memory is made up of a number of registers, each of which has a certain size and function. Usually, all the registers have the same size. Each register can hold one number, up to some maximum determined by the size of the register. Registers can be read and written at high speed since they are internal to the CPU. The most important register is the Program Counter (PC), which points to the next instruction to be fetched for execution. ( The name ‘‘program counter’’ is somewhat misleading because it has nothing to do with counting anything, but the term is universally used. Also important is the Instruction Register (IR), which holds the instruction currently being executed. ( Most computers have numerous other registers as well, some of the general-purpose as well as some for specific purposes.

What is the,,bus,,?

In computer architecture, a bus is a communication system that transfers data between components inside a computer, or between computers. This expression covers all related hardware components (wire, optical fiber, etc.) and software, including communication protocols.

Early computer buses were parallel electrical wires with multiple hardware connections, but the term is now used for any physical arrangement that provides the same logical function as a parallel electrical bus. Modern computer buses can use both parallel and bit-serial connections and can be wired in either a multi-drop(electrical parallel) or daisy chain topology, or connected by switched hubs, as in the case of USB.

CPU Organization

• A system bus is a link that connects every segment of a system to the central storage and carries out the data transfer in them.
• It is a pathway composed of cables and connectors which is used to carry data between a computer microprocessor and the main memory.
• It provides a communication path for the data and control signals moving between the major components of the computer system.

The types of system buses are

1. Data

• These are the pieces of information that are to be transferred.
• The data is transferred between peripherals, memory and the CPU. The data bus can be a very busy pathway.

2. Address

• It stores information about where the data is to be transferred.
• The components pass memory addresses to one another over the address bus.

3. Control

• These are the set of instructions regarding what to do with the data.
• It is used to send out signals to coordinate and manage the activities of the motherboard components.

Characteristics of a System Bus

1. Bus Width

• The size of a bus also known as its width.
• It determines how much data can be transferred at a time.
• This refers to the amount of information that can be transferred once.

2. Bus Speed

• This refers to the no. of bits or bytes the bus can send per unit time.
• It is also defined by its frequency. Frequency means that the number of data packets sent or received per second. Each time that data is sent or received is called a cycle.

The system bus combines the functions of the three main buses, namely Control Bus, Address Bus, Data Bus. The control bus carries the control, timing and coordination signals to manage the various functions across the system. The address bus is used to specify memory locations for the data being transferred.

The data bus, which is a bidirectional path. It carries the actual data between the processor (CPU), the memory and the peripherals (Input and Output). The system bus architecture varies from system to system and can be specific to a particular computer design. The other common characteristics of system buses are based on the primary role, connecting devices internally or externally, etc.

Internal Bus

• It is also known as an internal data bus, a memory bus, a system bus or Front-Side-Bus.
• It connects all the internal components of a computer, such as CPU and memory, to the motherboard.
• Internal data buses are also referred to as a local bus because they are intended to connect to local devices.
• This bus is quick and independent of the rest of the computer operations.

External Bus

• It is also known as an expansion bus.
• It is made up of the electronic pathways that connect the different external devices, such as a printer, etc.

Cache Function

A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, closer to a processor core, which stores copies of the data from frequently used main memory locations. Most CPUs have different independent caches, including instruction and data caches, where the data cache is usually organized as a hierarchy of more cache levels (L1, L2, etc.).

All modern (fast) CPUs (with few specialized exceptions) have multiple levels of CPU caches. The first CPUs that used a cache had only one level of cache; unlike later level 1 caches, it was not split into L1d (for data) and L1i (for instructions). Almost all current CPUs with caches have a split L1 cache. They also have L2 caches and, for larger processors, L3 caches as well. The L2 cache is usually not split and acts as a common repository for the already split L1 cache. Every core of a multi-core processor has a dedicated L2 cache and is usually not shared between the cores. The L3 cache, and higher-level caches, are shared between the cores and are not split. An L4 cache is currently uncommon and is generally on dynamic random access memory (DRAM), rather than on static random access memory (SRAM), on a separate die or chip. That was also the case historically with L1, while bigger chips have allowed integration of it and generally all cache levels, with the possible exception of the last level. Each extra level of cache tends to be bigger and be optimized differently.

Other types of caches exist (that are not counted towards the “cache size” of the most important caches mentioned above), such as the translation look aside buffer (TLB) that is part of the memory management unit (MMU) that most CPUs have.

Caches are generally sized in powers of two: 4, 8, 16 etc. KiB or MiB(for larger non-L1) sizes, although the IBM z13has a 96 KiB L1 instruction cache.

Instruction Execution Cycle

• This is a process of getting the instruction from the memory, decoding it to the machine language and executing it. So, three basic steps of the cycle are:

Fetch the instruction.
Decode it.
Execute.

• The whole process of fetching the instructions from the memory, decoding it to the machine language and executing it, is termed as an instruction cycle.

PRIMARY MEMORY

The memory is that part of the computer where programs and data are stored. Some computer scientists (especially British ones) use the term store or storage rather than memory, although more and more, the term ‘‘storage’’ is used to refer to disk storage. Without a memory from which the processors can read and write information, there would be no stored-program digital computers.

Bits

The basic unit of memory is the binary digit, called a bit. A bit may contain a 0 or a 1. It is the simplest possible unit. (A device capable of storing only zeros could hardly form the basis of a memory system; at least two values are needed.) People often say that computers use binary arithmetic because it is ‘‘efficient.’’ What they mean (although they rarely realize it) is that digital information can be stored by distinguishing between different values of some continuous physical quantity, such as voltage or current. The more values that must be distinguished, the less separation between adjacent values, and the less reliable the memory. The binary number system requires only two values to be distinguished. Consequently, it is the most reliable method for encoding digital information.

Memory Addresses

In computing, a memory address is a reference to a specific memory location used at various levels by software and hardware. Memory addresses are fixed-length sequences of digits conventionally displayed and manipulated as unsigned integers.Such numerical semantic bases itself upon features of CPU (such as the instruction pointer and incremental address registers), as well upon the use of the memory like an array endorsed by various programming languages.

 

 

Microprocessor

The microprocessor is the central unit of a computer system that performs arithmetic and logic operations, which generally include adding, subtracting, transferring numbers from one area to another, and comparing two numbers. It's often known simply as a processor, a central processing unit, or as a logic chip. It's essentially the engine or the brain of the computer that goes into motion when the computer is switched on. It's a programmable, multipurpose device that incorporates the functions of a CPU (central processing unit) on a single IC (integrated circuit).

Working

A microprocessor accepts binary data as input, processes that data, and then provides output based on the instructions stored in the memory. The data is processed using the microprocessor's ALU (arithmetical and logical unit), control unit, and a register array. The register array processes the data via a number of registers that act as temporary fast access memory locations. The flow of instructions and data through the system is managed by the control unit.

Benefits of a Microprocessor

But computer systems aren't the only devices that use microprocessors. Everything from smartphones to household appliances to cars use microprocessors these days. Here are a few reasons why microprocessors are so widely used:

• They don't cost a lot - Due to their use of IC technology, microprocessors don't cost much to produce. This means that the use of microprocessors can greatly reduce the cost of the system it's used in.
  
  
• They are fast - The technology used to produce modern microprocessors has allowed them to operate at incredibly high speeds--today's microprocessors can execute millions of instructions per second.
  
  
• They consume little power - Power consumption is much lower than other types of processors since microprocessors are manufactured using metal oxide semiconductor technology. This makes devices equipped with microprocessors much more energy efficient.
  
  
• They are portable - Due to how small microprocessors are and that they don't consume a lot of power, devices using microprocessors can be designed to be portable (like smartphones).
  
  
• They are reliable - Because semiconductor technology is used in the production of microprocessors, their failure rate is extremely low.
  
  
• They are versatile - The same microprocessor chip can be used for numerous applications as long as the programming is changed, making it incredibly versatile.

Categories of Microprocessors

Microprocessors can be classified in different categories, as follows:.

Based on Word Length

Microprocessors can be based on the number of bits the processor's internal data bus or the number of bits that it can process at a time (which is known as the word length). Based on its word length, a microprocessor can be classified as 8-bit, 16-bit, 32-bit, and 64-bit.

 

Reduced Instruction Set Computer (RISC)

RISC microprocessors are more general use than those that have a more specific set of instructions. The execution of instructions in a processor requires a special circuit to load and process data. Because RISC microprocessors have fewer instructions, they have simpler circuits, which means they operate faster. Additionally, RISC microprocessors have more registers, use more RAM, and use a fixed number of clock cycles to execute one instruction.

 

Complex Instruction Set Computer

CISC microprocessors are the opposite of RISC microprocessors. Their purpose is to reduce the number of instructions for each program. The number of cycles per instruction is ignored. Because complex instructions are made directly into the hardware, CISC microprocessors are more complex and slower. CISC microprocessors use little RAM, have more transistors, have fewer registers, have numerous clock cycles for each instruction, and have a variety of addressing modes.

 

Special Purpose Processors

Some microprocessors are built to perform specific functions. For example, coprocessors are used in combination with a main processor, while a transputer is a transistor computer: a microprocessor that has its own local memory.

Evolution of Microprocessors

We can categorize the microprocessor according to the generations or according to the size of the microprocessor:

First Generation (4 - bit Microprocessors)

The first generation microprocessors were introduced in the year 1971-1972 by Intel Corporation. It was named Intel 4004 since it was a 4-bit processor.

It was a processor on a single chip. It could perform simple arithmetic and logical operations such as addition, subtraction, Boolean OR and Boolean AND.

I had a control unit capable of performing control functions like fetching an instruction from storage memory, decoding it, and then generating control pulses to execute it.

Second Generation (8 - bit Microprocessor)

The second generation microprocessors were introduced in 1973 again by Intel. It was a first 8 - bit microprocessor which could perform arithmetic and logic operations on 8-bit words. It was Intel 8008, and another improved version was Intel 8088.

Third Generation (16 - bit Microprocessor)

The third generation microprocessors, introduced in 1978 were represented by Intel's 8086, Zilog Z800 and 80286, which were 16 - bit processors with a performance like minicomputers.

Fourth Generation (32 - bit Microprocessors)

Several different companies introduced the 32-bit microprocessors, but the most popular one is the Intel 80386.

Fifth Generation (64 - bit Microprocessors)

From 1995 to now we are in the fifth generation. After 80856, Intel came out with a new processor namely Pentium processor followed by Pentium Pro CPU, which allows multiple CPUs in a single system to achieve multiprocessing.

Other improved 64-bit processors are Celeron, Dual, Quad, Octa Core processors.

Ports

It the connection point acts as interface between the computer and the external devices like: printer, modem, etc.

There are two types of ports :

1. Internal Port –

It connects the system’s motherboard to internal devices like hard-disk, CD drive, internal Bluetooth etc.

2. External Port –

It connects the system’s motherboard to internal devices like mouse, printer, USB etc.

Some important types of ports are as per follows :

1. Serial Port :  

• Used for external modems and older computer mouse
• Two versions-9pin,25pin
• Data travels at 115 kilobits per second

2. Parallel Port :          

• Used for scanners and printers
• 25 pin model

3. Universal Serial Bus (USB) Port :

• It can connect all kinds of external USB devices such as external hard disk, printer, scanner, mouse, keyboard, etc.
• Data travels at 12 megabits per seconds.

4. Firewire Port :

• Transfers large amount of data at very fast speed.
• Connects camcorders and video equipment to the computer.
• Data travels at 400 to 800 megabits per seconds.

5. Ethernet Port :

• Connects to a network and high speed Internet.
• Data travels at 10 megabits to 1000 megabits per seconds depending upon the network bandwidth.

Domain Specific Tools

Depending upon of its usages, the software may be classified as generic or specific. Generic software is a software that can perform multiple tasks in a different environment without being modified like a word processor software that can be used by anyone to make different types of documents as a report, whitepaper, training material, etc. Specific software is software for a particular application, like railway reservation system, weather forecasting, etc.

Some Domain Specific Tools :

1. School Management System : School management system handles various activities and processes of a school to facilitate campus management like examination, attendance, admission, student’s fees, timetable, teacher’s training, etc. It provides a healthy interaction among teachers, students, parents.

2. Inventory Management : Managing multiple tasks like purchase, sales, order, delivery, stock maintenance, etc. associated with raw or processed goods in any business is called inventory management. The inventory management software ensures that stocks are never below specified limits and purchase/deliveries are done in time. Inventory management system is very useful for forecasting, utilizing economies of scale and timing.

3. Payroll Management System : Payroll management system deals with the financial aspects of the employee’s salary, taking care of leaves, bonus, loans, etc. Some advantages of using this kind of management system are managed employee information efficiently, generate pay-slip at the convenience of a mouse click, manages its own security. Payroll software is generally a component of HR (Human Resource) management software in big organizations.

4. Financial Accounting : Financial management software keeps an electronic record of all financial transactions of the organization. Objectives of financial accounting

   • Record financial transactions as and when they occur so that the data can be analyzed for preparing a financial statement.

   • Calculate profit or loss, to enable management to take course-correction strategies if required.

   • Ascertain the financial strength of the company by determining its assets and liabilities.

   • Communicate the information to stakeholders through statements and reports, so that these stakeholders can take appropriate decisions on their investments in the business.

5. Hotel Management :Hotel management software helps hotel managers to keep track of inventory levels, daily orders, customer management, employee scheduling, table booking, etc.

6. Reservation System :A reservation system is a software that handles multiple modules like train routes, train management, seat booking, meal booking, train maintenance, train status, travel package, etc.

7. Weather Forecasting System : Weather forecasting system is a real-time software that predicts the weather of a place by collecting live data about atmospheric temperature, humidity, wind level, etc. It is used to predict major disasters like earthquakes, hurricanes, tsunamis, etc.

Secondary Memory

All secondary storage devices which are capable of storing high volume data is referred to secondary memory. It's slower than primary memory. However, it can save a substantial amount of data, in the range of gigabytes to terabytes. This memory is also called backup storage or mass storage media.

Types of Secondary memory

Mass storage devices:

The magnetic disk provides cheap storage and is used for both small and large computer systems.

Two types of magnetic disks are:

• Floppy disks
• Hard disks

Flash/SSD

Solid State Drive provides a persistent flash memory. It's very fast compared to Hard Drives. Frequently found in Mobile phones, its rapidly being adopted in PC/Laptop/Mac.

Optical drives:

This secondary storage device is from which data is read and written with the help of lasers. Optical disks can hold data up to 185TB.

Examples

• CD
• DVD
• Blue Ray

USB drives:

It is one of the most popular types of secondary storage device available in the market. USB drives are removable, rewritable and are physically very small. The capacity of USB drives is also increasing significantly as today 1TB pen drive is also available in the market.

Magnetic tape:

It is a serial access storage device which allows us to store a very high volume of data. Usually used for backups.

Characteristic Secondary Memory

• These are magnetic and optical memories
• Secondary memory is known as a backup memory
• It is a non-volatile type of memory
• Data is stored permanently even when the power of the computer is switched off
• It helps store data in a computer
• The machine can run without secondary memory
• Slower than primary memory

Primary Memory

Primary memory is computer memory that is accessed directly by the CPU.RAM, or random access memory, consists of one or more memory modules that temporarily store data while a computer is running.

Primary memory is also known as Main memory or Internal memory.

RAM is volatile memory, meaning it is erased when the power is turned off.

Characteristic of Primary Memory

• The computer can't run without primary memory
• It is known as the main memory.
• You can lose data in case power is switched off
• It is also known as volatile memory
• It is a working memory of the computer.
• Primary memory is faster compares to secondary memory.

Two Types of Primary Memory are:

• RAM
• ROM

RAM

The full form of RAM is Random Access Memory. The information stored in this type of memory is lost when the power supply to the PC or laptop is switched off. The information stored in RAM can be checked with the help of BIOS. It is generally known as the main memory or temporary memory or cache memory or volatile memory of the computer system.

Two main types of RAM are:

• Static RAM
• Dynamic RAM

Static RAM

Static RAM is the full form of SRAM. In this type of RAM, data is stored using the state of a six transistor memory cell. Static RAM is mostly used as a cache memory for the processor (CPU).

Dynamic RAM

DRAM stands for Dynamic Random Access Memory. It is a type of RAM which allows you to stores each bit of data in a separate capacitor within a specific integrated circuit. Dynamic RAM is a standard computer memory of the many modern desktop computers.

This type of RAM is a volatile memory that needs to be refreshed with voltage regularly. Else it loses the information stored on it.

Uses of RAM

Here, are important uses of RAM:

• RAM is utilized in the computer as a scratchpad, buffer, and main memory.
• It offers a fast operating speed.
• It is also popular for its compatibility
• It offers low power dissipation

ROM

ROM (read only memory) is a flash memory chip that contains a small amount of non-volatile memory. Non-volatile means that its contents cannot be changed and it retains its memory after the computer is turned off.

Types of ROM

PROM: Programmable ROM, or PROM, is essentially a blank version of ROM that you can purchase and program once with the help of a special tool called a programmer. A blank PROM chip allows current to run through all possible pathways; the programmer chooses a pathway for the current by sending a high voltage through the unwanted fuses to “burn” them out. Static electricity can create the same effect by accident, so PROMs are more vulnerable to damage than conventional ROMs.

EPROM: Erasable Programmable ROM chips allow you to write and rewrite them many times. These chips feature a quartz window through which a specialized EPROM programmer emits a specific frequency of ultraviolet light. This light burns out all the tiny charges in the EPROM to reopen its circuits. This exposure effectively renders the chip blank again, after which you can reprogram it according to the same process as a PROM. EPROM chips will eventually wear out, but they frequently have lifetimes of over 1000 erasures.

EEPROM: To modify an Electrically Erasable Programmable ROM chip, apply localized electrical fields to erase and rewrite the data. EEPROMs have several advantages over other types of ROM. Unlike the earlier forms, you can rewrite EEPROM without dedicated equipment, without removing it from the hardware, and in specifically designated increments. You don’t have to erase and rewrite everything to make a single edit.

Cache Memory

Cache memory is an extremely fast memory type that acts as a buffer between RAM and the CPU. It holds frequently requested data and instructions so that they are immediately available to the CPU when needed. Cache memory is used to reduce the average time to access data from the Main memory.

Register

A processor register is a quickly accessible location available to a computer's processor. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only.

 

 

 

 

 

 

Software Concepts

A Computer is an electronic device that can perform various operations of computation at a greater speed than what an ordinary machine or human mind can do. It is driven by many entities including the physical and tangible components that we can touch or feel, called the Hardware and programs and commands that drive the hardware, called the Software.
The Software refers to the set of instructions fed in form of programs to govern the computer system and process the hardware components. For example:

• The antivirus that we use to protect our computer system is a type of Software.
• The media players that we use to play multimedia files such as movies, music etc. are Software.
• The Microsoft Office we use to edit the documents is a Software.

Depending on its use and area of implementation, Softwares can be divided into 3 major types:

1. System Software
2. Application Software
3. Utility Software

System Software

These are the software that directly allows the user to interact with the hardware components of a computer system. As the humans and machines follow different languages, there has to be an interface that will allow the users to interact with the core system, this interface is provided by the software. The system software can be called the main or the alpha software of a computer system as it handles the major portion of running a hardware. This System Software can be further divided into four major types:

1. The Operating System – It is the main program that governs and maintains the inter-cooperation of the components of a computer system. For eg., Microsoft Windows, Linux, Mac OS etc.
2. The Language Processor – The hardware components present in the computer system does not understand human language. There are three types of languages involved in the world of human-machine interaction:
   
    
   
   
   • Machine-Level Language: The machines only understand the digital signals or the binary codes or the binary language which consist of strings of 0’s and 1’s. These are totally machine dependent language.
   • Assembly-Level Language: These are the Low-Level Language(LLL), that forms a correspondence between machine level instruction and general assembly level statements. Assembly language uses a mnemonics to represent each low-level machine instruction or operation-code also called the op-codes. For eg., ADD instruction is used to add two entities, the HALT instruction is used to stop a process etc. It is a machine dependent language and varies from processor to processor.
   • High-Level Language: These are the simple English statements, that humans use to program and code as it is easy to read and understand to the human world. For eg., Java, C, C++, Python etc.

   The machine level language is very complex to understand and code, therefore the users prefer the High-Level Language or the HLL for coding. These codes need to be converted into the machine language so that the computer can easily understand and work accordingly. This operation is performed by the Language Processor which is made up of further three components:

   • Assembler: This language processor is used to convert the assembly language into machine level language.
   • Compiler: This language processor is used to convert High-Level Language into machine level language in one go, thus execution time is fast. The error detection is difficult in a compiler. Programming Languages like C, C++ and Scala use compiler.
   • Interpreter: This language processor is also used to convert High-Level Language into machine level language line-by-line, thus execution time is slow. Error-detection is easier in an interpreter as it reports as soon as a bug is caught and restarts the process. This consumes unnecessary memory. Programming Languages like Python, Ruby and Java uses an interpreter.
3. The Device Drivers – The device drivers and the device programs or the system software that acts as an interface between the various Input-Output device and the users or the operating system. For eg., the Printers, Web cameras come with a driver disk that is needed to be installed into the system to make the device run in the system.
4. The BIOS – It stands for Basic Input Output System and is a small firmware, that controls the peripheral or the input-output devices attached to the system. This software is also responsible for starting the OS or initiating the booting process.

Application Software

These are the basic software used to run to accomplish a particular action and task. These are the dedicated software, dedicated to performing simple and single tasks. For eg., a single software cannot serve to both the reservation system and banking system. These are divided into two types:

1. The General Purpose Application Software: These are the types of application software that comes in-built and ready to use, manufactured by some company or someone. For eg.,
   • Microsoft Excel – Used to prepare excel sheets.
   • VLC Media Player – Used to play audio/video files.
   • Adobe Photoshop – Used for designing and animation and many more.
2. The Specific Purpose Application Software: These are the type of software that is customizable and mostly used in real-time or business environment. For eg.,
   • Ticket Reservation System
   • Healthcare Management System
   • Hotel Management System
   • Payroll Management System

Utility Software

These are the most basic type of software which provides high utility to the user and the system. These perform the basic but daily need tasks. For eg.,

• Antivirus Softwares: These provide protection to the computer system from unwanted malware and viruses. For eg., QuickHeal, McAfee etc.
• Disk Defragmenter Tools: These help the users to analyse the bad sectors of the disk and rearrange the files in a proper order.
• Text-editors: These help the users to take regular notes and create basic text files. For eg., Notepad, Gedit etc.

Device Drivers

A device driver is a small piece of software that tells the operating system and other software how to communicate with a piece of hardware.

For example, printer drivers tell the operating system, and by extension whatever program you have the thing you want to print open in, exactly how to print information on the page

sound card drivers are necessary so your operating system knows exactly how to translate the 1s and 0s that comprise that MP3 File  into audio signals that the sound card can output to your headphones or speakers. 

The same general idea applies to video cards, keyboards, monitors, mice, disc drivers, etc.

Keep reading for more on why drivers are important, including some more examples, as well as information on how to keep your drivers updated and what to do if they're not working properly.

Working of Device Driver:
Device Drivers depend upon the Operating System’s instruction to access the device and performing any particular action. After the action they also shows their reactions by delivering output or status/message from hardware device to the Operating system.For Example a printer driver tells the printer in which format to print after getting instruction from OS, similarly A sound card driver is there due to which 1’s and 0’s data of MP3 file is converted to audio signals and you enjoy the music. Card reader, controller, modem, network card, sound card, printer, video card, USB devices, RAM, Speakers etc need Device Drivers to operate.

Office Tools

Office Tools include some Application Software that are used to create, update, manage documents, handle large data, create presentations etc. These tools if used effectively, can save a large amount of time and effort. Lots of repetitive tasks can be done very easily. In this article, we will discuss the following concepts:

• Word Processor
• Presentation Tool
• Spreadsheet Package
• Database Management System

1. Word Processor

Word Processor is a software that is used to manage text documents. User can create, update and formatting text files using word processor. It makes text document related work faster an easier. A word processor is an essential part of any office suite. A word processor usually runs on local machine as a desktop application like Microsoft word but nowadays cloud based Word Processors like Google docs are also used which makes it easier for teams to manage their documents on cloud.

Examples of some word processors are:

• MS-Word: Retail Cross-Platform word processor
• WordPad: Retail windows only word processor
• WordPerfect: Retail Cross-Platform word processor
• Google Docs: Freeware Cloud Based word processor
• LibreOffice Writer: Open Source word processor

Characteristics of word processor:

• Create, save and edit text documents.
• Includes text formatting like font size, alignment, font color, background color, etc.
• Checks spelling.
• Allows adding images, screenshots etc to document.
• Allows adding header and footer, set page margins and insert watermarks to your document.

2. Presentation Tool

A Presentation Tool is a software package used to display data and information in the form of a slide show. The information is broken into small pieces called slides. It has three major parts: editor that allows formatting and editing of text, method used for inserting and manipulating graphic images, screenshots etc, slide-show system to display the content in form of a slide show.

The Slides together are stacked up to make an idea presentable to audience to make up presentation.

Examples of some presentation tool are:

• MS-PowerPoint: Retail Cross-Platform presentation tool
• Lotus Freelance: proprietary software presentation tool
• Google Slides: Freeware Cloud Based presentation tool
• LibreOffice Impress: Open Source presentation tool

3. Spreadsheet Package

Spreadsheet Package is a software that allows users to store, process and modify data in a tabular form easily. It is an accounting tool to manage tabular data. In a Spreadsheet data is always stored in cells. A cell is intersection of rows and columns. functions and formulas can be used easily on cell and data can be processed using a spreadsheet tool.

Examples of some spreadsheet software are:

• MS-Excel: Retail Cross-Platform spreadsheet package
• Google Sheets: Freeware Cloud Based spreadsheet package
• LibreOffice Calc: Open Source spreadsheet package

Characteristics of spreadsheet package:

• User can handle simple calculations like addition, subtraction, average, counting, etc, very easily.
• User can Prepare charts and graphs on a group of data easily.
• Data formatting is efficient and effective.
• Cell formatting is easy.
• Logical Calculations can be done.

4. Database Management System

Database Management System is a software that manages data by storing them in tables to make up a database. A database is an organised collection of data accessed on a machine. A Database Management System interacts with data, users and application. User can store, read, update and can delete data based on his/her needs. A good DBMS provides a set of utilities to administrator to manage the data effectively.

Examples of some Database Management System are:

• MySQL
• PostgreSQL
• Oracle Database
• Microsoft Access.

Characteristics of Database Management System:

• Data storing, reading and updating.
• User accessibility.
• Recovering damaged data facilities.
• Authorization of administrator and data access.
• Defining constraints for dataset.

 

Classification of Computers

The computer systems can be classified on the following basis:

1. On the basis of size.
2. On the basis of functionality.
3. On the basis of data handling.

According to purpose, computers are either general purpose or specific purpose. General purpose computers are designed to perform a range of tasks. They have the ability to store numerous programs, but lack in speed and efficiency. Specific purpose computers are designed to handle a specific problem or to perform a specific task. A set of instructions is built into the machine.

Type of computers on the basis of Functionality & Data Handling:

Analog Computer 

 An analog computer (spelt analogue in British English) is a form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved.

Digital Computer

 A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system.

Hybrid computer

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

Type of computers on the basis of Size:

Super Computer 

The fastest and most powerful type of computer Supercomputers are very expensive and are employed for specialized applications that require immense amounts of mathematical calculations. For example, weather forecasting requires a supercomputer. Other uses of supercomputers include animated graphics, fluid dynamic calculations, nuclear energy research, and petroleum exploration.

The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently.

Mainframe Computer

A very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. In the hierarchy that starts with a simple microprocessor (in watches, for example) at the bottom and moves to supercomputers at the top, mainframes are just below supercomputers. In some ways, mainframes are more powerful than supercomputers because they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe.

Mini Computer 

A mid sized computer. In size and power, minicomputers lie between workstations and mainframes. In the past decade, the distinction between large minicomputers and small mainframes has blurred, however, as has the distinction between small minicomputers and workstations. But in general, a minicomputer is a multiprocessing system capable of supporting from 4 to about 200 users simultaneously.

Micro Computer or Personal Computer

• Desktop Computer: a personal or micro-mini computer sufficient to fit on a desk.

• Laptop Computer: a portable computer complete with an integrated screen and keyboard. It is generally smaller in size than a desktop computer and larger than a notebook computer.

• Palmtop Computer/Digital Diary /Notebook /PDAs: a hand-sized computer. Palmtops have no keyboard but the screen serves both as an input and output devices.

Workstations

A terminal or desktop computer in a network. In this context, workstation is just a generic term for a user’s machine (client machine) in contrast to a “server” or “mainframe.”

 

 

System software

A system software is a specific type of software that manages a computing device. The system software comprises the operating system, utility programmes, and device drivers. We will look at each of the three parts.

The system software is a collection of programs designed to operate, control, and extend the processing capabilities of the computer itself. System software is generally prepared by the computer manufacturers. These software products comprise of programs written in low-level languages, which interact with the hardware at a very basic level. System software serves as the interface between the hardware and the end users.

Some examples of system software are Operating System, Compilers, Interpreter, Assemblers, etc.

Here is a list of some of the most prominent features of a system software −

• Close to the system
• Fast in speed
• Difficult to design
• Difficult to understand
• Less interactive
• Smaller in size
• Difficult to manipulate
• Generally written in low-level language

AN OPERATING SYSTEM

An operating system is software that manages hardware, software and other applications on a computing device. The operating system has different functions and tasks it carries out on a computing device. In order to make these functions easy to understand, they are grouped into the following categories:

• Disk management: Used to manage the drives installed in a computer e.g. partition drives, format drives, assign drive letters.
• Hardware management: Managing the interaction between hardware and software, as well as the different hardware devices.
• Graphics User Interface (GUI) management: Provides and manages the user interface that interacts with graphics and visual content on a computing device.
• I/O management: Managing the signals received from an input device and sending the correct signals to an output device.
• Process management: Managing the applications and the resources used by applications (Apps) on a computing device.
• File management: Managing the storage of files and folders on your storage device.
• Memory management: Managing the data stored on a computing device’s memory and once the processing is complete, this function tends to free up some space.
• Storage management: Processes used to improve the performance of data storage resources.

Types of operating systems

Up to now, you have been learning about and working with Microsoft Windows as an example of an operating system. This particular type of operating system is commonly known as a stand-alone operating system. In this unit, we will focus on the following three types of operating systems namely, stand-alone, network and embedded operating systems.

THE STAND-ALONE OPERATING SYSTEM

These operating systems function entirely independently from a network on a computer or mobile device. This ensures that the tasks of an operating system can be performed on the device.

THE NETWORK OPERATING SYSTEM

Network or server operating systems are operating systems designed to help computers work together on a network, rather than used in a stand-alone mode. For example, a large company may have a server running the Windows Server operating system in the organisation. A computer can connect to the same network to gain access to its information, resources, etc. Examples include: Windows Server, Red Hat Enterprise, Ubuntu Server, and UNIX.

THE EMBEDDED OPERATING SYSTEM

The embedded operating system is designed for a specific purpose e.g. Smart TVs that connect to the internet, a video camera (Wi-Fi) that can stream live footage and the GPS system that is installed in most mobile devices.

Compiler

A compiler is a special program that processes statements written in a particular programming language and turns them into machine language or "code" that a computer's processor uses. Typically, a programmer writes language statements in a language such as Pascal or C one line at a time using an editor.

Interpreter

In computer science, an interpreter is a computer program that directly executes instructions written in a programming or scripting language, without requiring them previously to have been compiled into a machine language program.

Assembler

An assembler is a program that converts assembly language into machine code. It takes the basic commands and operations from assembly code and converts them into binary code that can be recognized by a specific type of processor. Assemblers are similar to compilers in that they produce executable code.

Difference Between Compiler Interpreter and Assembler

Functionality

Compiler converts the whole high level language program to machine language at a time. Interpreter converts the high level language program to machine language line by line. In contrast, assembler converts assembly language program to machine language.

Language

Languages such as C, C++ use compilers to convert the code. Languages such as Ruby, Perl, Python, PHP uses an interpreter and assembly language uses an assembler.

Conclusion

Compiler, Interpreter and Assembler are language translators. The difference between compiler interpreter and assembler is that compiler converts whole high level language programs to machine language at a time while interpreter converts high level language programs to machine language line by line and assembler converts assembly language programs to machine language.

 

 

 

Utility software

Utility software is software designed to help to analyze, configure, optimize or maintain a computer. It is used to support the computer infrastructure - in contrast to application software, which is aimed at directly performing tasks that benefit ordinary users.

Utility software usually focuses on how the computer infrastructure (including the computer hardware, operating system, software and data storage) operates. Utility software, along with operating system software, is a type of system software, distinguishing it from application software.

• Anti Virus utilities scan for computer viruses.

• Archivers output a stream or a single file when provided with a directory or a set of files. Archive utilities, unlike archive suites, usually do not include compression or encryption capabilities. Some archive utilities may even have a separate un-archive utility for the reverse operation.

• Backup Software can make copies of all information stored on a disk and restore either the entire disk (e.g. in an event of disk failure) or selected files (e.g. in an event of accidental deletion).

• Clipboard Managers expand the clipboard functionality of an operating system .

• Cryptographic utilities encrypt and decrypt streams and files.

• Data Compression utilities output a shorter stream or a smaller file when provided with a stream or file.

• Data Synchronization utilities establish consistency among data from a source to a target data storage and vice versa. There are several branches of this type of utility:

  • File Synchronizatiion utilities maintain consistency between two sources. They may be used to create redundancy or backup copies but are also used to help users carry their digital music, photos and video in their mobile devices.

  • Revision Control utilities are intended to deal with situations where more than one user attempts to simultaneously modify the same file.

• Debuggers are used to test and “debug” other programs, mainly to solve programming errors. Also utilized for reverse engineering of software or systems.

• Disk Checkers can scan operating hard drive.

• Disk Cleaners can find files that are unnecessary to computer operation, or take up considerable amounts of space. Disk cleaner helps the user to decide what to delete when their hard disk is full.

• Disk Compression utilities can transparently compress/uncompress the contents of a disk, increasing the capacity of the disk.

• Disk Defregmenters can detect computer files whose contents are scattered across several locations on the hard disk, and move the fragments to one location to increase efficiency.

• Disk Partitions can divide an individual drive into multiple logical drives, each with its own file system which can be mounted by the operating system and treated as an individual drive.

• Disk Space Analysers for the visualization of disk space usage by getting the size for each folder (including sub folders) & files in folder or drive. showing the distribution of the used space.

• Disk Storage utilities

• File Managers provide a convenient method of performing routine data management tasks, such as deleting, renaming, cataloging, uncataloging, moving, copying, merging, generating and modifying data sets.

• Hex Editiors directly modify the text or data of a file. These files could be data or an actual program.

• Memory Testers check for memory failures.

• Network Utilities analyze the computer’s network connectivity, configure network settings, check data transfer or log events.

• Package Managers are used to configure, install or keep up to date other software on a computer.

• Registry Cleaners clean and optimize the Windows Registry by removing old registry keys that are no longer in use.

• Screensavers were desired to prevent phosphor burn-in on CRT and plasma computer monitors by blanking the screen or filling it with moving images or patterns when the computer is not in use. Contemporary screensavers are used primarily for entertainment or security.

• System Monitors for monitoring resources and performance in a computer system.

• System Profilers provide detailed information about the software installed and hardware attached to the computer.

 

Functions of Operating System

An operating system has three main functions:

(1) manage the computer's resources, such as the central processing unit, memory, disk drives, and printers.

(2) establish a user interface.

(3) execute and provide services for applications software.

Operating System supports the basic functions of the computer and is a low-level software. The functions of operating systems are as described below:

i)  I/O Management:

OS manages I/O devices and makes the I/O process effective. OS accepts the input from the input device, stores it in the main memory, ask the CPU to process it and finally provides the result to the output devices for output.

ii) Command Interpreter:

Command interpreter is one of the part of operating system which reads the commands that user types in at a terminal, interprets them and translate them into a detailed set of instructions that the computer hardware can understand. It varies widely from one OS to other OS. Every OS must provide command interpreter for its operation.

iii) Memory Management:

Memory is the large array of words or bytes, each with its own address. When user requests CPU for read/write operation, OS determines the amount of memory required for the program instructions and data. Then, OS allocates required memory to load the program and data into RAM. When program terminates its memory area is free and the same memory area is allocated for other programs.

iv)  Process Management:

OS finds the status of processor and processes, chooses a job, chooses processer in the job, allocates the processor to the process and frees the processor when the process is executed.

v)  Time Sharing:

OS manages the time of CPU. The kernel OS checks frequency for other processes requesting CPU time. Time-sharing checks for CPU request from higher priority processes that are made every 10 milliseconds. When two or more processes at the same priority level are competing for the CPU time, CPU time is sliced into segments, defined by time slice and passed from process to process in a round robin fashion, preventing a single process from monopolizing the CPU until it blocks or terminates.

vi)  Security:

OS makes sure that only authorized users get access to the computer and its data and the users only do things they are authorized to do.

vii) Deadlock Prevention:

During processing, a situation can arise in which a resource shared by two or more processes cannot continue because the resource required by one process is held by the other. This situation is called deadlock. OS ensures that the above condition do not hold by carefully allocating resources.

viii)  Interrupt Handling:

Interrupt is a signal generated from a device or program when they need attention of the CPU. OS determines the type of interrupt and priority of the interrupt, stops the execution process of CPU, preserves the initial state of the CPU, perform the requested operation and brings the CPU at the same state when it was stopped.

ix) Virtual Storage:

If there are programs larger than main memory (RAM) of the computer, OS uses the reserved space in the secondary memory which is termed as virtual memory. It makes the execution of larger program (than RAM) possible but at the same times the operation becomes slower.

Features of Operating System (OS)

Here is a list important features of OS:

• Protected and supervisor mode
• Allows disk access and file systems Device drivers Networking Security
• Program Execution
• Memory management Virtual Memory Multitasking
• Handling I/O operations
• Manipulation of the file system
• Error Detection and handling
• Resource allocation
• Information and Resource Protection

 

 

 

Basics of computer

A computer is a machine that can be instructed to carry out sequences of arithmetic or logical operations automatically via computer programming. Modern computers have the ability to follow generalized sets of operations, called programs. These programs enable computers to perform an extremely wide range of tasks. A "complete" computer including the hardware, the operating system (main software), and peripheral equipment required and used for "full" operation can be referred to as a computer system. This term may as well be used for a group of computers that are connected and work together, in particular a computer network or computer cluster.

Computers are used as control system for a wide variety of industrial and consumer devices. This includes simple special purpose devices like microwave oven and remote contols, factory devices such as industrial robots and computer-aided design, and also general purpose devices like persnol computer and mobile devices such as smartphones. The Internet is run on computers and it connects hundreds of millions of other computers and their users.

Characteristics of Computer

1. Speed: – As you know computer can work very fast. It takes only few seconds for calculations that we take hours to complete. You will be surprised to know that computer can perform millions (1,000,000) of instructions and even more per second.

Therefore, we determine the speed of computer in terms of microsecond (10-6 part of a second) or nanosecond (10 to the power -9 part of a second). From this you can imagine how fast your computer performs work.

2. Accuracy: – The degree of accuracy of computer is very high and every calculation is performed with the same accuracy. The accuracy level is 7.

 

determined on the basis of design of computer. The errors in computer are due to human and inaccurate data.

3. Diligence: – A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work.

4. Versatility: – It means the capacity to perform completely different type of work. You may use your computer to prepare payroll slips. Next moment you may use it for inventory management or to prepare electric bills.

5. Power of Remembering: – Computer has the power of storing any amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data.

 

6. No IQ: – Computer is a dumb machine and it cannot do any work without instruction from the user. It performs the instructions at tremendous speed and with accuracy. It is you to decide what you want to do and in what sequence. So a computer cannot take its own decision as you can. 

7. No Feeling: – It does not have feelings or emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users.

8. Storage: – The Computer has an in-built memory where it can store a large amount of data. You can also store data in secondary storage devices such as floppies, which can be kept outside your computer and can be carried to other computers.

Basic Parts of Computer

Computer case

The computer case is the metal and plastic box that contains the main components of the computer, including the motherboard, central processing unit (CPU), and power supply. The front of the case usually has an On/Off button and one or more optical drives.

Computer cases come in different shapes and sizes. A desktop case lies flat on a desk, and the monitor usually sits on top of it. A tower case is tall and sits next to the monitor or on the floor. All-in-one computers come with the internal components built into the monitor, which eliminates the need for a separate case.

Monitor

The monitor works with a video card, located inside the computer case, to display images and text on the screen. Most monitors have control buttons that allow you to change your monitor's display settings, and some monitors also have built-in speakers.

Newer monitors usually have LCD (liquid crystal display) or LED (light-emitting diode) displays. These can be made very thin, and they are often called flat-panel displays. Older monitors use CRT (cathode ray tube) displays. CRT monitors are much larger and heavier, and they take up more desk space.

Keyboard

The keyboard is one of the main ways to communicate with a computer. There are many different types of keyboards, but most are very similar and allow you to accomplish the same basic tasks.

Mouse

The mouse is another important tool for communicating with computers. Commonly known as a pointing device, it lets you point to objects on the screen, click on them, and move them.

There are two main mouse types: optical and mechanical. The optical mouse uses an electronic eye to detect movement and is easier to clean. The mechanical mouse uses a rolling ball to detect movement and requires regular cleaning to work properly.

Mouse alternatives

There are other devices that can do the same thing as a mouse. Many people find them easier to use, and they also require less desk space than a traditional mouse. The most common mouse alternatives are below.

• Trackball: A trackball has a ball that can rotate freely. Instead of moving the device like a mouse, you can roll the ball with your thumb to move the pointer.
• Touchpad: A touchpad—also called a trackpad—is a touch-sensitive pad that lets you control the pointer by making a drawing motion with your finger. Touchpads are common on laptop computers.

Advantages Of Computer

Computer has made a very vital impact on society. It has changed the way of life. The use of computer technology has affected every field of life. People are using computers to perform different tasks quickly and easily. The use of computers makes different task easier. It also saves time and effort and reduces the overall cost to complete a particular task.

Many organizations are using computers for keeping the records of their customers. Banks are using computers for maintaining accounts and managing financial transactions. The banks are also providing the facility of online banking. The customers can check their account balance from using the internet. They can also make financial transaction online. The transactions are handled easily and quickly with computerized systems.

People are using computers for paying their bills, managing their home budgets or simply having some break and watching a movie, listening to songs or playing computer games. Online services like skype or social media websites are used for communication and information sharing purposes.

Computer can be used as a great educational tool. Students can have access to all sort of information on the internet. Some great websites like Wikipedia, Khan’s Academy, Code Academy, Byte-Notes provides free resources for students & professionals. 

Disadvantages Of Computer

The use of computer has also created some problems in society which are as follows.

Unemployment

Different tasks are performed automatically by using computers. It reduces the need of people and increases unemployment in society.

Wastage Of Time And Energy

Many people use computers without positive purpose. They play games and chat for a long period of time. It causes wastage of time and energy. Young generation is now spending more time on the social media websites like Facebook, Twitter etc or texting their friends all night through smartphones which is bad for both studies and their health. And it also has adverse effects on the social life.

Data Security

The data stored on a computer can be accessed by unauthorized persons through networks. It has created serious problems for the data security.

Computer Crimes

People use the computer for negative activities. They hack the credit card numbers of the people and misuse them or they can steal important data from big organizations.

Privacy Violation

The computers are used to store personal data of the people. The privacy of a person can be violated if the personal and confidential records are not protected properly.

Health Risks

The improper and prolonged use of computer can results in injuries or disorders of hands, wrists, elbows, eyes, necks and back. The users can avoid health risks by using the computer in proper position. They must also take regular breaks while using the computer for longer period of time. It is recommended to take a couple of minutes break after 30 minutes of computer usage.

Impact On Environment

The computer manufacturing processes and computer waste are polluting the environment. The wasted parts of computer can release dangerous toxic materials. Green computer is a method to reduce the electricity consumed and environmental waste generated when using a computer. It includes recycling and regulating manufacturing processes. The used computers must be donated or disposed off properly.