Resource Management

Primary Memory
●​ Definition: Also known as main memory, it's the computer's fast-access memory that is
directly accessible by the CPU.
●​ Types:
○​ RAM (Random Access Memory): Volatile memory used to store data and
instructions that the CPU is currently using.
○​ ROM (Read-Only Memory): Non-volatile memory that stores essential system
instructions, such as the BIOS (Basic Input/Output System).
●​ Function: Provides the CPU with quick access to the data and instructions it needs to
execute programs.
Secondary Storage
●​ Definition: Non-volatile memory used to store data and programs persistently, even
when the computer is turned off.
●​ Types:
○​ Hard Disk Drives (HDDs): Traditional magnetic storage devices.
○​ Solid State Drives (SSDs): Faster, more durable storage devices that use flash
memory.
○​ Optical Discs (CDs, DVDs, Blu-rays): Removable storage media.
○​ USB Flash Drives: Portable, solid-state storage devices.
●​ Function: Provides long-term storage for data and programs.
Processor Speed
●​ Definition: The rate at which a CPU can execute instructions, typically measured in
Hertz (Hz) or Gigahertz (GHz).
●​ Factors Affecting Speed: Clock speed, number of cores, architecture, cache memory.
●​ Importance: A higher processor speed generally means faster program execution and
better system performance.
Bandwidth
●​ Definition: The amount of data that can be transmitted over a network connection in a
given amount of time, usually measured in bits per second (bps).
●​ Types:
○​ Network Bandwidth: The maximum rate of data transfer across a network.
○​ Memory Bandwidth: The rate at which data can be read from or written to
memory.
●​ Importance: Higher bandwidth allows for faster data transfer, which is crucial for
network communication and overall system performance.
Screen Resolution
●​ Definition: The number of pixels displayed on a screen, expressed as width x height
(e.g., 1920x1080).
●​ Impact on Image Quality: A higher resolution means more pixels, resulting in a
sharper, more detailed image.
Disk Storage
●​ Definition: The amount of data that can be stored on a secondary storage device (e.g.,
 HDD, SSD).
●​ Units: Measured in bytes, kilobytes (KB), megabytes (MB), gigabytes (GB), terabytes
(TB).
●​ Importance: Determines how much data and how many programs can be stored on a
computer.
Sound Processor
●​ Definition: A dedicated processor that handles audio processing, converting digital
audio data into analog signals that can be sent to speakers.
●​ Function: Enhances audio quality, supports surround sound, and offloads audio
processing from the CPU.
Graphics Processor (GPU)
●​ Definition: A specialized electronic circuit designed to rapidly manipulate and alter
memory to accelerate the creation of images in a frame buffer intended for output to a
display device.
●​ Function: Accelerates the rendering of images, videos, and 3D graphics, freeing up the
CPU for other tasks.
Cache
●​ Definition: A small, fast memory that stores frequently accessed data and instructions,
located closer to the CPU than main memory.
●​ Levels: L1, L2, and L3 cache, with L1 being the fastest and smallest.
●​ Function: Reduces the average time it takes to access data from memory, significantly
improving system performance.
Network Connectivity
●​ Definition: The ability of a computer or device to connect to a network.
●​ Types: Wired (e.g., Ethernet) and wireless (e.g., Wi-Fi).
●​ Importance: Enables communication, resource sharing, and access to online services.
Mainframes
●​ Definition: Large, powerful computers used by organizations to process large amounts
of data and run critical applications.
●​ Characteristics: High reliability, high processing capacity, and the ability to support
many users simultaneously.
●​ Use Cases: Banking, insurance, and other industries that require high-volume
transaction processing.
Servers
●​ Definition: Computers that provide services to other computers (clients) over a
network.
●​ Types: Web servers, email servers, file servers, database servers.
●​ Function: Manage network resources, store data, and provide access to services.
PCs (Personal Computers)
●​ Definition: General-purpose computers designed for individual use.
●​ Types: Desktop computers, laptop computers.
●​ Use Cases: Home, office, and educational use.
Sub-laptops
 ●​ Definition: Small, lightweight laptops that prioritize portability.
●​ Examples: Ultrabooks, netbooks.
●​ Use Cases: Mobile computing, travel.
Cell Phones
●​ Definition: Mobile devices that combine communication, computing, and multimedia
capabilities.
●​ Function: Voice calls, text messaging, internet access, running apps.
PDAs (Personal Digital Assistants)
●​ Definition: Handheld devices that provide computing and information storage and
retrieval capabilities for personal or business use.
●​ Function: Scheduling, note-taking, and database capabilities.
Digital Cameras
●​ Definition: Devices that capture and store photographs and videos in digital form.
●​ Function: Image and video recording.
Single Processor Computers and 3D Graphics
●​ Justification: Single-processor computers may struggle with 3D graphics rendering
due to the high computational demands of 3D graphics.
○​ 3D rendering involves complex calculations for geometry, lighting, textures, and
animations.
○​ A single processor has to handle all these calculations, along with other system
tasks, which can lead to performance bottlenecks and slow frame rates.
○​ Modern 3D graphics applications and games often require the parallel processing
capabilities of multiple CPU cores or dedicated GPUs to achieve smooth and
realistic visuals.
User Time Wasted Due to Inadequate Hardware
●​ Primary Memory (RAM): If RAM is too small:
○​ The computer may resort to swapping data between RAM and the hard drive
(virtual memory), which is much slower.
○​ This can lead to excessive disk activity, slow application loading times, and system
sluggishness, significantly wasting user time.
●​ Processor Speed: If the processor speed is inadequate:
○​ Applications will run slowly, and tasks will take longer to complete.
○​ The user may experience delays when opening files, browsing the web, or
performing other common tasks, leading to wasted time and frustration.
Multi-access and Multiprogramming Environments
●​ Multi-access Systems: Allow multiple users to access the computer system
simultaneously (e.g., time-sharing systems, mainframes).
○​ Need to manage user access, allocate resources, and ensure data security.
●​ Multiprogramming Systems: Allow multiple programs to reside in memory at the same
time, enabling the operating system to switch between them to improve CPU utilization.
○​ Require sophisticated memory management and scheduling algorithms.
●​ Single-user Systems: Designed for use by a single user at a time (e.g., personal
computers).
 ○​ Simpler in design and resource management compared to multi-user systems.
Role of the Operating System
The operating system (OS) is a software that manages computer hardware and provides
services for computer programs. Its key roles include:
●​ Managing Memory:
○​ Allocating storage space in RAM for programs and data.
○​ Keeping track of program locations in memory.
○​ Swapping programs between RAM and secondary storage (virtual memory) to
handle more programs than can fit in RAM at once.
●​ Managing Peripherals:
○​ Communicating with input/output devices (e.g., keyboard, mouse, printer).
○​ Using device drivers to translate commands between the OS and the hardware.
●​ Managing Hardware Interfaces:
○​ Providing a consistent interface for applications to interact with hardware.
○​ Hiding the complexity of the hardware from applications.
OS Resource Management Techniques
●​ Scheduling: Determining which processes should be executed by the CPU and in what
order.
●​ Policies: Rules that govern how resources are allocated and managed.
●​ Multitasking: Allowing multiple processes to run concurrently by rapidly switching the
CPU between them.
●​ Virtual Memory: A technique that allows a process to use more memory than is
physically available by swapping portions of it to disk.
●​ Paging: A memory management technique that divides memory into fixed-size blocks
called pages.
●​ Interrupt: A signal from a device or software that interrupts the CPU's current activity
and transfers control to an interrupt handler.
●​ Polling: The process of repeatedly checking the status of a device or resource.
Advantages of a Dedicated Operating System
A dedicated operating system is designed for a specific device or purpose. Advantages
include:
●​ Size: Can be optimized to be smaller, requiring less storage space.
●​ Speed: Can be optimized for the specific hardware, resulting in faster performance.
●​ Customization: Can be tailored to the device's specific functions and user interface
requirements.
Pros and Cons of a Dedicated OS for a Cell Phone
●​ Pros:
○​ Optimized performance for the phone's hardware.
○​ Smaller size, saving storage space.
○​ Customized user interface for mobile use.
○​ Improved battery life.
●​ Cons:
○​ Limited application availability compared to a general-purpose OS.
 ○​ Less flexibility for users to customize the system.
○​ Higher development costs.
Pros and Cons of Proprietary Software
●​ Pros:
○​ Often comes with better support and documentation.
○​ May be more polished and user-friendly.
○​ Can be optimized for specific hardware.
●​ Cons:
○​ Can be expensive.
○​ Users have limited control over the software.
○​ Vendor lock-in: users are tied to a specific vendor.
○​ Source code is not available, hindering customization and modification.
How an OS Hides Hardware Complexity
An OS abstracts the underlying hardware, providing a simplified interface for users and
applications. Examples:
●​ Drive Letters: The OS assigns letters (e.g., C:, D:) to physical storage devices, allowing
users to access them without needing to know the specific hardware details.
●​ Virtual Memory: The OS creates the illusion of more RAM than is physically available,
allowing programs to use a larger address space.
●​ Input Devices: The OS provides a consistent interface for different input devices (e.g.,
keyboard, mouse), so applications don't need to handle the specific details of each
device.
●​ Java Virtual Machine (JVM): The JVM provides a platform-independent environment
for Java applications, allowing them to run on different operating systems without
modification. The JVM abstracts the differences between the underlying hardware and
OS.
Issue of Localization
●​ Localization: The process of adapting software to a specific language, culture, and
region.
●​ Compatibility Problems: Localization can lead to compatibility problems between
systems in different countries due to:
○​ Different character encodings (e.g., ASCII, Unicode).
○​ Varying date, time, and number formats.
○​ Different keyboard layouts.
○​ Language-specific features and requirements.