2. Hardware and Software

(Incomplete)

Mainframe computers and super computers

Mainframe Computers

• used by large organizations for bulk data processing
• applications:
  • censuses,
  • statistics,
  • transaction processing
• Larger and more powerful than personal computers, laptops, or tablets.
• Cost at least $75,000 in 2020.
• Originated with large CPUs housed in steel cabinets ("main frame" or "big iron").
• Evolved significantly despite the rise of PCs.
• Notable feature: Reliability, Availability, and Serviceability (RAS).
• Modern PCs have multi-core CPUs for parallel processing.
• Mainframes have hundreds of processor cores for multitasking and multi-user operations.
• Size has decreased from room-sized to large cupboard-sized.
• Resistant to viruses and Trojan horses.
• Used mainly in commercial organizations, less known to the general public.
• example:
  • most advanced mainframe so far is: IBM z15 (the capinet itself is taller than the average person)
  • has 190 cores

Characteristics

• Longevity
  • Great longevity, can run continuously for long periods.
  • Used by governments, banks, and telecom companies.
  • Expensive to shut down and dispose of hardware securely.
  • COBOL language still in use, but fewer professionals trained in it.
  • Threats: Lack of skilled professionals, rise of Cloud computing.
  • Solution: Combine mainframes with Cloud computing.
  • Efficiency and dependability maintain popularity.
• RAS (Reliability, Availability, Serviceability)
  • Reliability: Processors self-check for errors and recover without impact.
  • Availability: High availability with long MTBF (Mean time between failures) and quick recovery from failures.
  • Serviceability: Can identify failure causes and replace components with minimal impact (with least/no downtime).
• Security
  • High level of data security, crucial for handling large volumes of personal data.
  • Security features:
    • Multi-factor authentication,
    • levels of access,
    • data encryption,
    • secure operating systems,
    • continual monitoring
• Performance Metrics
  • Speed measured in MIPS (Millions of Instructions Per Second).
  • Benchmark tests used to compare performance.
  • Cost often linked to MIPS.
• Volume of Input, Output, and Throughput
  • Specialized hardware for input/output operations.
  • Handles very large data volumes (terabytes).
  • High throughput with billions of transactions per day.
• Fault Tolerance
  • Can continue operating despite component failures.
  • Hardware and software redundancy ensures minimal disruption.
• Operating System
  • Can run multiple OS simultaneously (z/OS, z/VM®, Linux®).
  • Efficient parallel processing with task division among processor cores.
• Type of Processor
  • Hundreds of processor cores.
  • Term 'CPU complexes' is used to describe multiple processors by some manufacturers.
• Heat Maintenance
  • Historically used liquid cooling, now a mix of air and water cooling.
  • More powerful systems require effective heat management.

Uses

• Banking Sector
  • Process billions of transactions daily.
  • Handle large volumes of data for batch processing (e.g., overnight bank statements, backups).
• Census Data Processing
  • Manage enormous data from population surveys.
  • Historically used since the 1950s (e.g., UNIVAC 1).
  • Some countries still rely on mainframes despite advances in PC processing power.
• Industry Statistics
  • Process data on businesses, employees, and wages.
  • Help companies understand market trends and competitors.
• Consumer Statistics
  • Analyze demand for products, household incomes, and employment status.
  • Assist in pricing, marketing, and understanding market saturation.
• Transaction Processing
  • Execute multiple operations to complete single transactions (e.g., bank transfers).
  • Ensure error-free operations, maintaining data integrity.
  • Designed for continuous availability and fault tolerance.

Advantages

• High Reliability
  • Rarely experience system downtime.
  • Can handle hardware and software upgrades without shutting down.
• Performance
  • Continuously improving in speed and power.
  • Outperform PCs, laptops, and other devices.
• Data Handling
  • Capable of storing and processing vast amounts of data.
  • Can run different operating systems and handle data in various formats.
• Security
  • Equipped with strong encryption systems and complex authorization procedures

Diadvantages

• Cost
  • Very expensive to purchase.
  • High costs for personnel required to run and maintain them.
• Physical Space
  • Require large rooms for housing.
  • Advanced cooling systems needed, increasing installation and running costs.
• Cloud Migration
  • Many organizations are moving to Cloud-based services to avoid buying their own systems.
  • Mainframe software is more expensive compared to Cloud services.

Super Computers

• More powerful than mainframes.
• Can have over 100,000 processing cores.
• Capable of massive parallel processing.
• Example: Summit supercomputer at Oak Ridge National Laboratory (2018).
• Summit's performance: Can perform tasks in 1 second that would take the world population 305 days.
• Size: Fills a room the size of two tennis courts.
• example:
  • Cray XC40 supercomputer
    • 172 000 processor cores.
    • Several countries have one of these for weather forecasting, scientific research, computational modelling

Characteristics

• Longevity
  • Short lifespan of about five years.
  • Constantly replaced by faster models in research institutions and meteorology.
• RAS (Reliability, Availability, Serviceability)
  • Not typically associated with supercomputers.
• Security
  • High level of security, often with end-to-end encryption.
  • Used for sensitive data storage like DNA profiles.
• Performance Metrics
  • Speed measured in FLOPS (Floating Point Operations Per Second).
  • Speeds now measured in petaflops (PFLOPS), with future targets of exaflops (EFLOPS).
• Volume of Input, Output, and Throughput
  • Designed for maximum processing power and speed.
  • Throughput is a characteristic of mainframes, not supercomputers.
• Fault Tolerance
  • High likelihood of component failures due to the large number of processors.
  • Similar fault tolerance approaches as mainframes but more prone to interruptions.
• Operating System
  • Typically runs one OS, usually Linux.
  • Uses massively parallel processing with many processor cores, each with its own OS.
• Type of Processor
  • Hundreds of thousands of processor cores.
  • Uses multiple GPUs (Graphics Processing Units).
• Heat Maintenance
  • Significant overheating issues due to high power consumption.
  • Requires direct liquid cooling to manage heat.

Uses

• National Defense and Data Encryption
  • Design nuclear weapons.
  • Encrypt sensitive data.
• Scientific Research and Quantum Mechanics
  • Perform calculations for atomic and subatomic particle behavior.
  • Example: Juqueen and Juwels supercomputers in Germany.
• Weather Forecasting
  • Process data from weather stations, satellites, etc.
  • Create models to predict future weather patterns.
  • Example: UK Meteorological Office uses Cray XC40 supercomputers.
• Climate Research
  • Analyze long-term environmental data.
  • Predict climate change impacts.
  • Use models like the Community Earth System Model (CESM).
• Drug Research
  • Develop new medications by comparing new compounds with past research.
  • Monitor ingredient interactions and predict drug efficacy and side effects.
• Genetic Analysis
  • Identify genes linked to diseases.
  • Reduce research time from months to minutes.

Advantages

• Processing Speed
  • The fastest data processing computers available
• Massively Parallel Processing
  • Utilizes massively parallel processing, making them more powerful than mainframes and PCs.

Diadvantages

• Cost
  • Extremely expensive to buy and install (e.g., Summit supercomputer costs $200 million).
• Operating Systems
  • Typically have one operating system, unlike mainframes which can support multiple.
• Fault Tolerance
  • Less fault-tolerant than mainframes.
  • More downtime compared to mainframes, though less than other systems.

Comparison

Advantages vs Disadvantages of Mainframe Computers and Supercomputers

Category	Advantages	Disadvantages
Mainframe Computers	High reliability Continuous operation during upgrades Increasing speed and power Handles vast amounts of data Runs different operating systems Strong security	High purchase cost Expensive maintenance and personnel Requires large physical space High cooling system costs Cloud migration preferred Expensive software
Supercomputers	Fastest data processing Massively parallel processing	Extremely expensive Typically one operating system Less fault-tolerant More downtime than mainframes

Mainframe Computers vs. Supercomputers

Aspect	Mainframe Computers	Supercomputers
Primary Use	Transaction processing, batch processing, large-scale data handling	Scientific research, simulations, complex calculations
Speed	High speed, optimized for throughput	Extreme speed, optimized for parallel processing
Cost	Expensive to purchase and maintain	Extremely expensive to purchase and install
Reliability	Very high reliability, minimal downtime	Reliable, but less fault-tolerant than mainframes
Security	Strong security features, complex encryption	High security, but focused more on processing power than encryption
Operating Systems	Supports multiple operating systems	Usually runs on a single operating system
Usage Examples	Banking transactions Census data processing Industry statistics	Weather forecasting Climate research Drug research and simulations

System Software

• refers to programs that control a computer's hardware and application software.

Compilers

• Translate high-level programming languages into machine code (binary form) that the processor can execute.
• Process:
  • Translate source code (high-level language) into object code (machine code)
  • Often requires multiple passes through the program for error checking and resolving references.
  • Produces a list of error messages after translation.
• Output:
  • Compiled programs are executable files
  • that run directly without needing the compiler present
  • (will sometimes need a runtime environment with all the DLLs (Dynamic Link Libraries) to link to)
• Languages:
  • Early examples include FORTRAN, COBOL, and LISP;
  • modern examples are C++, C#, Visual Basic, Pascal.

Interpreters

• Translate and execute high-level language programs one statement at a time.
• Process:
  • Converts source code into an intermediate form and executes it immediately.
  • Stops translation at the first error encountered,
    • allowing for immediate debugging.
  • Each statement is translated every time it is executed,
    • requiring the interpreter to be in memory during execution.
• Advantages:
  • Portable between different operating systems.
  • Useful for program development with immediate execution and error feedback.
  • Saves memory as only a few lines need to be in memory at a time.
• Examples:
  • Python often uses a combination of compilation (to bytecode) and interpretation (via a virtual machine).
  • Same story with Java, compiled to Java Bytecode and intepreted in Java Virtual Machine (JVM).

Compilers vs Intepreters

	Compilers	Interpreters
Advantages	Faster execution after compilation. Does not require source code at runtime, enhancing security. Once compiled, does not need to be translated again.	Easier debugging with immediate error feedback. Cross-platform compatibility with the appropriate interpreter. Requires less memory as only parts of the program are loaded at a time.
Disadvantages	More memory-intensive during compilation. Error messages are provided after the whole program is compiled, making debugging harder. Compiled programs are OS-specific and need recompilation for different systems.	Slower execution as each statement is translated before execution. Requires source code to be present at runtime, risking copyright infringement. Translation needed every time the program runs, making it less efficient.

Linkers

• Linker is short for 'link editor'
• Combine object files or modules created by a compiler into a single executable file.
• Process:
  • Modules are written separately and then linked together.
  • Allows large programs to be compiled in smaller parts, conserving RAM.
  • Object code from different modules is saved on storage and combined later.
• Advantages:
  • Facilitates modular programming, reducing memory requirements.
  • Simplifies error correction as only the faulty module needs fixing.
• Challenges:
  • Variable name conflicts.
  • Requires detailed documentation for module integration.

Device Drivers

• Enable the OS and application software to communicate with hardware devices.
• Role:
  • Acts as an interface between software and hardware.
  • Translates software commands into hardware-specific instructions.
• Importance:
  • Essential for the operation of hardware devices.
  • Many drivers are included with the OS for basic functionality.
  • Specialized features of hardware require specific drivers.
  • Drivers are OS-specific; a driver for one OS may not work on another.
• Examples:
  • Printer drivers,
  • sound cards,
  • monitors,
  • mice,
  • SSDs,
  • network cards,
  • keyboards,
  • disk drives.

Operating Systems (OS)

• Manage computer hardware and software resources, acting as an interface between the user and the computer.

Features

• Memory Management:
  • Allocates RAM for each program and ensures data integrity.
  • Prevents data corruption by managing program memory allocation.
• Input/Output Management:
  • Handles data input and output via device drivers.
  • Communicates with input devices and sends data to output devices like printers.
• File Management:
  • Manages file storage and retrieval.
  • Keeps track of file locations and available storage space.
• Multitasking:
  • Allocates CPU time to multiple tasks/programs.
  • Manages task execution to ensure fair resource distribution.
• Error Handling:
  • Displays error messages and requires user intervention for resolution.
• Security:
  • Manages user login and password encryption.
  • Controls file permissions and access rights.
• System Shutdown:
  • Closes running software safely.
  • Gradually shuts down the OS and signals the hardware to power off.

Boot Process

• BIOS: Basic Input/Output System stored in ROM, executes during boot-up.
• OS Loading: Instructions for loading the OS are in ROM; the main OS is loaded from the hard disk.

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• Sequence of steps that a computer system goes through when it is powered on or restarted

• Involves several stages, including hardware checks, loading the BIOS, initializing hardware components, and finally loading the operating system

• Steps:

  • Power On
    • The power supply sends a signal to the motherboard and the processor
  • POST (Power On Self Test)
    • The BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware Interface) firmware is activated.
    • The BIOS performs a POST to check if the essential hardware components (memory, keyboard, storage devices, etc.) are functioning correctly.
    • If the POST is successful, the BIOS continues the boot process. If not, it generates error messages or beep codes.
  • Load BIOS/UEFI Settings
    • The BIOS/UEFI initializes and configures the hardware components.
    • The BIOS/UEFI settings can be configured by the user to manage hardware configurations and boot priorities.
  • Locate and Load Boot Loader
    • The BIOS/UEFI looks for a boot loader in the bootable device (usually specified in the BIOS settings).
    • The boot loader is a small program that loads the operating system. Common boot loaders include GRUB (for Linux) and Windows Boot Manager.
  • Load Operating System
    • The boot loader loads the kernel of the operating system into memory.
    • The operating system initializes its components, drivers, and services.
  • Initialize User Interface
    • Once the OS is fully loaded, it initializes the user interface, allowing the user to interact with the system.
    • This includes loading the login screen or directly presenting the desktop environment.

1. Power On

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2. Power-On Self-Test (POST)

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3. Load BIOS/UEFI Settings

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4. Locate and Load Boot Loader

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5. Load Operating System

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6. Initialize User Interface

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Utility Software

• I probably wont complete this.