Computers: Supercomputers, Mainframes, and Minis

Supercomputers

• Capable of processing trillions of instructions per second due to thousands of interconnected processors.
• Primarily used in scientific and engineering applications like weather forecasting, simulations, and nuclear research.
• Can perform up to ten trillion calculations per second, making them extremely fast.
• Vital in financial sectors for stock market analysis and managing cryptocurrencies like Bitcoin.
• Employed in scientific research for data analysis from space exploration and satellite information.

Mainframe Computers

• Designed to support hundreds or thousands of users simultaneously and execute multiple programs at once.
• Ideal for large organizations such as banks and telecom companies that handle significant data volumes.
• High storage capacity, great performance, and long operational life.
• Expensive compared to other types of computers.

Minicomputers

• Medium-sized multiprocessing computers that support 4 to 200 users at a time.
• Typically used in departments and institutions for tasks like billing and inventory management.
• Smaller than mainframe computers but larger than microcomputers.
• Lightweight, portable, and less expensive than mainframes while still being fast.

Workstation Computers

• Tailored for technical or scientific applications with fast microprocessors and substantial RAM.
• Generally a single-user system aimed at specific tasks requiring high accuracy.
• High-speed graphic adapters are common, enhancing performance for graphic-intensive tasks.

Computer Storage Devices

• Storage devices are crucial for data retention in computers, allowing for temporary and permanent information storage.

Primary Storage Devices

• RAM (Random Access Memory): Temporary storage for immediate use; data is lost when powered off.
  • Types of RAM:
    • SRAM: Static RAM, faster and more expensive, used for cache memory.
    • DRAM: Dynamic RAM, slower but cheaper, requires refreshing.
    • SDRAM: Synchronous DRAM, faster than regular DRAM.
• ROM (Read-Only Memory): Non-volatile storage for permanent system instructions.
  • Types include MROM, PROM, EPROM, and EEPROM, varying in programmability and erasure capabilities.

Secondary Memory

• Also known as auxiliary memory; non-volatile and used for long-term data storage.
• Slower than primary memory but affordable and offers a higher storage capacity.
• The data must first be moved to primary memory before being accessed by the CPU.

Cache Memory

• High-speed memory acting as a buffer between CPU and main memory.
• Stores frequently used data, enabling faster access.
• Advantages include speed and efficiency; disadvantages include high costs and limited size.

Virtual Memory

• Allows larger memory usage by combining physical memory with disk space.
• Uses paging and segmentation to manage and optimize memory use for applications.

Logic Gates

• Digital circuits that control the flow of electrical signals based on logical conditions.
• Truth Table: Displays input-output combinations for logic gates.
• AND Gate: Outputs 1 if both inputs are 1.
• OR Gate: Outputs 1 if at least one input is 1.
• NOT Gate: Outputs the inverse of the input.
• NAND Gate: Outputs 1 unless both inputs are 1.
• NOR Gate: Outputs 1 only when both inputs are 0.
• XNOR Gate: Outputs 1 when inputs are the same, 0 otherwise.