Tag: Operating Systems

Network Topology refers to the arrangement or layout of different elements (such as nodes, links, and devices) in a computer network. It defines how devices are connected and how data flows within the network. Common network topologies include bus, star, ring, mesh, tree, and hybrid. Each topology has its own advantages and disadvantages in terms of cost, scalability, reliability, and performance. The choice of network topology impacts the network’s efficiency, fault tolerance, and ease of maintenance. A well-designed topology is crucial for optimizing network performance and ensuring smooth communication.

Types of Network Topology:

The arrangement of a network which comprises of nodes and connecting lines via sender and receiver is referred as network topology. The various network topologies are:-

1. Mesh Topology

In mesh topology, every device is connected to another device via particular channel.

Every device is connected with another via dedicated channels. These channels are known as links.

• If suppose, N number of devices are connected with each other in mesh topology, then total number of ports that is required by each device is ​ N-1. In the Figure 1, there are 5 devices connected to each other, hence total number of ports required is 4.
• If suppose, N number of devices are connected with each other in mesh topology, then total number of dedicated links required to connect them is NC2 i.e. N(N-1)/2. In the Figure 1, there are 5 devices connected to each other, hence total number of links required is 5*4/2 = 10.

Advantages of Mesh Topology

• It is robust.
• Fault is diagnosed easily. Data is reliable because data is transferred among the devices through dedicated channels or links.
• Provides security and privacy.

Problems with Mesh Topology

• Installation and configuration is difficult.
• Cost of cables are high as bulk wiring is required, hence suitable for less number of devices.
• Cost of maintenance is high.

2. Star Topology

​ In star topology, all the devices are connected to a single hub through a cable. This hub is the central node and all others nodes are connected to the central node. The hub can be passive ​in nature i.e. not intelligent hub such as broadcasting devices, at the same time the hub can be intelligent known as active ​hubs. Active hubs have repeaters in them.

A star topology having four systems connected to single point of connection i.e. hub.

Advantages of Star Topology

• If N devices are connected to each other in star topology, then the number of cables required to connect them is N. So, it is easy to set up.
• Each device require only 1 port i.e. to connect to the hub.

Problems with Star Topology

• If the concentrator (hub) on which the whole topology relies fails, the whole system will crash down.
• Cost of installation is high.
• Performance is based on the single concentrator i.e. hub.

3. Bus Topology

​ Bus topology is a network type in which every computer and network device is connected to single cable. It transmits the data from one end to another in single direction. No bi-directional feature is in bus topology.

A bus topology with shared backbone cable. The nodes are connected to the channel via drop lines.

Advantages of Bus Topology

• If N devices are connected to each other in bus topology, then the number of cables required to connect them is 1 ​which is known as backbone cable and N drop lines are required.
• Cost of the cable is less as compared to other topology, but it is used to built small networks.

Problems with Bus Topology

• If the common cable fails, then the whole system will crash down.
• If the network traffic is heavy, it increases collisions in the network. To avoid this, various protocols are used in MAC layer known as Pure Aloha, Slotted Aloha, CSMA/CD etc.

4. Ring Topology

​ In this topology, it forms a ring connecting a devices with its exactly two neighbouring devices.

A ring topology comprises of 4 stations connected with each forming a ring..

The following operations takes place in ring topology are:-

One station is known as monitor station which takes all the responsibility to perform the operations.

To transmit the data, station has to hold the token. After the transmission is done, the token is to be released for other stations to use.

When no station is transmitting the data, then the token will circulate in the ring.

There are two types of token release techniques: Early token release releases the token just after the transmitting the data and Delay token release releases the token after the acknowledgement is received from the receiver.

Advantages of Ring topology

• The possibility of collision is minimum in this type of topology.
• Cheap to install and expand.

Problems with Ring topology

• Troubleshooting is difficult in this topology.
• Addition of stations in between or removal of stations can disturb the whole topology.

5. Hybrid Topology

​This topology is a collection of two or more topologies which are described above. This is a scalable topology which can be expanded easily. It is reliable one but at the same it is a costly topology.

A hybrid topology which is a combination of ring and star topology.

Operating System serves as the backbone of a computer, ensuring the coordination of processes, memory, devices, and applications. It is designed to simplify the interaction between users and hardware by providing a user-friendly interface and ensuring efficient resource utilization.

Primary objectives of an OS:

1. Managing computer hardware resources such as the CPU, memory, and storage.
2. Providing a platform for application software to run.
3. Ensuring security and access control for users and processes.
4. Enhancing user convenience by offering tools and utilities.

Functions of an Operating System

• Process Management:

The OS handles process creation, execution, and termination. It schedules processes for efficient CPU usage, prioritizes tasks, and manages multitasking, ensuring the smooth functioning of multiple applications simultaneously.

• Memory Management:

It allocates and deallocates memory space for applications and processes. By managing RAM effectively, the OS ensures no process overwrites another and maximizes system performance.

• File System Management:

OS provides a structured way to store, retrieve, and manage data on storage devices. It organizes files in directories, handles file permissions, and ensures data integrity.

• Device Management:

The OS acts as a mediator between hardware devices and applications. It manages device drivers, facilitates communication, and ensures that devices like printers, keyboards, and monitors operate seamlessly.

• User Interface:

The OS provides interfaces such as Graphical User Interface (GUI) and Command Line Interface (CLI), allowing users to interact with the computer system. GUIs, like Windows and macOS, are more user-friendly, while CLIs, like Linux shells, cater to advanced users.

• Security and Access Control:

Operating systems safeguard data and resources through user authentication, permissions, and encryption. They protect the system from malware, unauthorized access, and data breaches.

• Networking:

Modern operating systems enable networking by managing communication between computers through protocols. This facilitates resource sharing and connectivity over local and global networks.

Types of Operating Systems:

• Batch Operating Systems:

Batch OS processes jobs in batches without user interaction. It is ideal for systems requiring bulk data processing, like payroll systems, but lacks real-time feedback.

• Time-Sharing Operating Systems:

OS types allow multiple users to access a system simultaneously by allocating a time slice for each user, enabling efficient multitasking.

• Distributed Operating Systems:

A distributed OS manages a group of independent computers and makes them appear as a single system. It facilitates resource sharing and parallel processing.

• Real-Time Operating Systems (RTOS):

RTOS is used in systems where timely task execution is critical, such as in medical devices, automotive systems, and robotics.

• Mobile Operating Systems:

Designed for smartphones and tablets, mobile OSs like Android and iOS focus on touchscreen interactions, app ecosystems, and connectivity.

• Network Operating Systems:

These OS types manage network resources, allowing file sharing, printer access, and centralized security for multiple users.

Examples of Operating Systems

1. Microsoft Windows: Known for its user-friendly GUI, Windows dominates personal and business desktops.
2. Linux: Open-source and versatile, Linux is popular for servers, developers, and enthusiasts.
3. macOS: Developed by Apple, macOS offers seamless integration with Apple devices and a secure environment.
4. Android: The most widely used mobile OS, known for its customization and vast app ecosystem.
5. iOS: Apple’s mobile OS, offering high security, fluid user experience, and exclusive features.

Importance of Operating Systems

• Efficiency:

By managing resources like CPU, memory, and storage, the OS ensures smooth operation and prevents conflicts between processes.

• User Convenience:

Modern OSs offer intuitive interfaces, making computers accessible even to non-technical users.

• Security:

Operating systems protect sensitive data and resources from unauthorized access and cyber threats.

• Interoperability:

OSs enable applications to run seamlessly across hardware platforms.

CENTRAL PROCESSING UNIT (CPU)

Central processing unit (CPU) is the central component of the Computer System. Sometimes it is called as microprocessor or processor. It is the brain that runs the show inside the Computer. All functions and processes that is done on a computer is performed directly or indirectly by the processor. Obviously, computer processor is one of the most important element of the Computer system. CPU is consist of transistors, that receives inputs and produces output. Transistors perform logical operations which is called processing. It is also, scientifically, not only one of the most amazing parts of the PC, but one of the most amazing devices in the world of technology.

Motherboard

Alternatively referred to as the mb, mainboard, mboard, mobo, mobd, backplane board, base board, main circuit board, planar board, system board, or a logic board on Apple computers. The motherboard is a printed circuit board and foundation of a computer that is the biggest board in a computer chassis. It allocates power and allows communication to and between the CPU, RAM, and all other computer hardware components.

A motherboard provides connectivity between the hardware components of a computer, like the processor (CPU), memory (RAM), hard drive, and video card. There are multiple types of motherboards, designed to fit different types and sizes of computers.

Each type of motherboard is designed to work with specific types of processors and memory, so they are not capable of working with every processor and type of memory. However, hard drives are mostly universal and work with the majority of motherboards, regardless of the type or brand.

Microprocessor

Microprocessor is a controlling unit of a micro-computer, fabricated on a small chip capable of performing ALU (Arithmetic Logical Unit) operations and communicating with the other devices connected to it.

Microprocessor consists of an ALU, register array, and a control unit. ALU performs arithmetical and logical operations on the data received from the memory or an input device. Register array consists of registers identified by letters like B, C, D, E, H, L and accumulator. The control unit controls the flow of data and instructions within the computer.

How does a Microprocessor Work?

The microprocessor follows a sequence: Fetch, Decode, and then Execute.

Initially, the instructions are stored in the memory in a sequential order. The microprocessor fetches those instructions from the memory, then decodes it and executes those instructions till STOP instruction is reached. Later, it sends the result in binary to the output port. Between these processes, the register stores the temporarily data and ALU performs the computing functions.

List of Terms Used in a Microprocessor

Here is a list of some of the frequently used terms in a microprocessor −

• Instruction Set − It is the set of instructions that the microprocessor can understand.
• Bandwidth − It is the number of bits processed in a single instruction.
• Clock Speed − It determines the number of operations per second the processor can perform. It is expressed in megahertz (MHz) or gigahertz (GHz).It is also known as Clock Rate.
• Word Length − It depends upon the width of internal data bus, registers, ALU, etc. An 8-bit microprocessor can process 8-bit data at a time. The word length ranges from 4 bits to 64 bits depending upon the type of the microcomputer.
• Data Types − The microprocessor has multiple data type formats like binary, BCD, ASCII, signed and unsigned numbers.

Features of a Microprocessor

Here is a list of some of the most prominent features of any microprocessor −

• Cost-effective: The microprocessor chips are available at low prices and results its low cost.
• Size: The microprocessor is of small size chip, hence is portable.
• Low Power Consumption: Microprocessors are manufactured by using metaloxide semiconductor technology, which has low power consumption.
• Versatility: The microprocessors are versatile as we can use the same chip in a number of applications by configuring the software program.
• Reliability: The failure rate of an IC in microprocessors is very low, hence it is reliable.

The Intel Pentium III AMD

The Pentium III model, introduced in 1999, represents Intel’s 32-bit x86 desktop and mobile microprocessors in accordance with the sixth-generation P6 micro-architecture.

The Pentium III processor included SDRAM, enabling incredibly fast data transfer between the memory and the microprocessor. Pentium III was also faster than its predecessor, the Pentium II, featuring clock speeds of up to 1.4 GHz. The Pentium III included 70 new computer instructions which allowed 3-D rendering, imaging, video streaming, speech recognition and audio applications to run more quickly.

The Pentium III processor was produced from 1999 to 2003, with variants codenamed Katmai, Coppermine, Coppermine T and Tualatin. The variants’ clock speeds varied from 450 MHz to 1.4 GHz. The Pentium III processor’s new instructions were optimized for multimedia applications called MMX. It supported floating-point units and integer calculations, which are often required for still or video images to be modified for computer displays. The new instructions also supported single instruction multiple data (SIMD) instructions, which allowed a type of parallel processing.

Other Intel brands associated with the Pentium III were Celeron (for low-end versions) and Xeon (for high-end versions).

Cyrix

Cyrix Corporation was a microprocessor developer that was founded in 1988 in Richardson, Texas, as a specialist supplier of math coprocessors for 286 and 386 microprocessors. The company was founded by Tom Brightman and Jerry Rogers. Cyrix founder, President and CEO Jerry Rogers, aggressively recruited engineers and pushed them, eventually assembling a small but efficient design team of 30 people.

Cyrix merged with National Semiconductor on 11 November 1997.

The first Cyrix product for the personal computer market was a x87 compatible FPU coprocessor. The Cyrix FasMath 83D87 and 83S87 were introduced in 1989. The FasMath provided up to 50% more performance than the Intel 80387. Cyrix FasMath 82S87, a 80287-compatible chip, was developed from the Cyrix 83D87 and has been available since 1991.

MMX Technology

MMX is a Pentium microprocessor from Intel that is designed to run faster when playing multimedia applications. According to Intel, a PC with an MMX microprocessor runs a multimedia application up to 60% faster than one with a microprocessor having the same clock speed but without MMX. In addition, an MMX microprocessor runs other applications about 10% faster, probably because of increased cache. All of these enhancements are made while preserving compatibility with software and operating systems developed for the Intel Architecture.

MMX is a single instruction, multiple data (SIMD) instruction set designed by Intel, introduced in January 1997 with its P5-based Pentium line of microprocessors, designated as “Pentium with MMX Technology”. It developed out of a similar unit introduced on the Intel i860, and earlier the Intel i750 video pixel processor. MMX is a processor supplementary capability that is supported on recent IA-32 processors by Intel and other vendors.

The New York Times described the initial push, including Super Bowl ads, as focused on “a new generation of glitzy multimedia products, including videophones and 3-D video games.”

MMX has subsequently been extended by several programs by Intel and others: 3DNow!, Streaming SIMD Extensions (SSE), and ongoing revisions of Advanced Vector Extensions (AVX).

Main Memory / Primary Memory refers to the computer’s temporary data storage that directly interacts with the central processing unit (CPU). It is where data and programs that are currently being used or processed are stored for quick access. Unlike secondary storage devices like hard drives or SSDs, which are used for long-term storage, main memory is much faster but volatile, meaning that it loses its contents when the computer is turned off.

Types of Main Memory:

1. RAM (Random Access Memory):

RAM is the most common type of main memory and is considered volatile. When a program is executed, it is loaded into RAM so that the CPU can access it quickly. RAM allows data to be read or written in any order, making it very fast. It is divided into two main types:

1. • Dynamic RAM (DRAM): This type of RAM needs to be constantly refreshed to maintain the stored data. It is slower compared to static RAM but is more cost-effective.
   • Static RAM (SRAM): SRAM stores data without needing constant refreshing, making it faster but more expensive than DRAM. It is typically used in cache memory and for storing data in registers.

2. Cache Memory:

Cache memory is a small, high-speed memory located closer to the CPU. It stores frequently accessed data and instructions that the CPU uses to speed up processing. Cache memory helps reduce the time it takes for the CPU to access data from main memory. There are usually multiple levels of cache:

• • L1 Cache: Located directly on the CPU chip, it is the smallest and fastest cache level.
  • L2 Cache: It is larger than L1 and can be located either on the CPU or nearby, offering a balance between speed and size.
  • L3 Cache: It is the largest but slower than L1 and L2, often shared across multiple CPU cores.

3. ROM (Read-Only Memory):

ROM is non-volatile, meaning it retains its data even when the power is turned off. ROM stores firmware, which is permanent software that is directly programmed into the hardware. This memory is used for basic functions like booting up the computer and performing hardware initialization. There are different types of ROM, such as PROM (Programmable ROM), EPROM (Erasable Programmable ROM), and EEPROM (Electrically Erasable Programmable ROM), which allow varying levels of data modification.

Importance and Function:

Main memory plays a crucial role in system performance. It provides fast access to data that the CPU needs to execute instructions efficiently. Without adequate main memory, a computer would be much slower, as the CPU would frequently need to retrieve data from slower storage devices like hard drives or SSDs. Additionally, as more programs run simultaneously, more main memory is required to keep everything running smoothly. This is why modern computers are often equipped with large amounts of RAM and high-speed cache memory.