Computer System Management Quiz

Course Content

• Introduction
• File System Management
• Storage Management
• Process Management
• CPU Scheduling
• Threading
• Memory Management
• Virtual Memory Management

Computer System

• Hardware: input units, CPU, output units, secondary storage
  • Examples: Monitor, keyboard, CPU, disks, memory, etc.
• Software: Operating Systems, application programs, compilers, interpreters
• Users: those who use the computer system

Application Programs

• Programs installed to perform a specific task
• Usually written in high-level languages (Python, Java, C++)
• Examples: web browsers, email, word processors, excel, etc.

Computer System Internal Structure

• Input Units: used to input data and instructions to memory
  • Examples: keyboard, mouse, scanner, microphone, camera
• Output Units: used to display output
  • Examples: printer, monitor, speaker
• Main Memory:
  • RAM: stores user programs and data
  • ROM: stores fixed programs used by the computer
  • Cache Memory: increases processor speed
• Control Unit: controls the sequence of operations, receives instructions/information from main memory
• Processor: performs required tasks using Arithmetic and Logic Unit (ALU)
• Secondary Storage Unit: stores data permanently
  • Examples: hard disk, optical disk, floppy disk
• Arithmetic and Logical Unit (ALU): performs arithmetic and logical operations on binary numbers
  • Outputs change in response to input

Memory Components

• Primary Storage/Main Memory: directly accessed by the CPU
  • RAM: random access memory, volatile (loses content when power off), modifiable by user
  • ROM: read-only memory, non-volatile, contains fixed programs (like boot program)
  • Cache memory: inside processor, stores frequently used data, increases processor speed

Secondary Storage Units

• Used to store data permanently, not directly accessible by CPU
  • Magnetic Disk: metal/plastic coated with magnetic material, rotates at high speed; divided into tracks and sectors
    • Hard Disk: large, fixed
    • Floppy Disk: small, movable
  • Magnetic Tape: plastic film coated with magnetic material; used to store large volumes of data in mainframe computers
  • Compact Disks (CD/ROM): plastic surface with reflective material, laser beam used to write/read, can store up to 600 MB
  • Flash Drive/Pen Drive: data transport between systems, compact
  • Memory Card: card-shaped, similar to flash drive, used to store large amounts of data; plugs into a port and easily removable

Operating System

• Program running constantly to manage computer components (Kernel)
• Creates an environment for other programs to operate efficiently
• Goals: Convenient user experience and efficient system performance
• Spooling: way to process data serially (example: printer)
• Print Spooler: puts print requests in a queue and executes them sequentially

Operating System Types

• Batch System: users send jobs to an operator, organized into batches, each batch runs separately
  • Example: Payroll systems, bank statements
• Multi-Programming System: multiple processes in memory waiting for CPU (one user). Example: Windows OS
• Multi-Tasking (Time Sharing) System: allows multiple users to share CPU simultaneously
  • Example: IBM VM/CMS, TSO, Windows Terminal Services
• Multi-Processor System: many processors to distribute tasks, thus increase speed
• Network Operating System: manages networks, resource sharing, computational speedup
• Real-Time System: performs critical tasks requiring immediate execution; critical tasks need on-time execution, e.g., operating systems for surgical devices
  • Types: Hard Real-Time (critical tasks must be done on time), Soft Real-Time (critical tasks can be a little late)
• Examples: Scientific Experiments, Medical Imaging Systems, Industrial Control Systems, Weapon Systems, Robots, Air Traffic Control Systems

Operating System Functions

• Process Management
• Memory Management
• File Management
• Storage Management
• I/O Management
• Protection Management
• Networking Management

Driver Programs

• Introduced by hardware manufacturers, allowing operating systems to communicate with hardware.

Programming Languages

• High-Level Languages: resemble natural languages, require compilers (or interpreters) for machine language conversion
  • Example: Visual Basic, Java, C, etc.
• Low-Level Languages: resemble machine languages, require assemblers to convert to machine language
  • Example: Assembly Language

Compilers vs. Interpreters

• Both translate high-level language to machine language.
• Interpreters translate line-by-line.
• Compilers translate the whole program in one step.
• Compilers give complete error messages upfront, while interpreters give errors for each line individually.

Operating System Examples

• Windows (commercial, multiple versions)
• Linux (open-source, multiple variations)
• Mac OS (Unix-based)
• iOS (mobile, developed by Apple)
• Android (mobile, based on Linux)
• Other older systems: Solaris, VMS, OS/400, AIX, z/OS

Operating System History

• Early systems limited to running one program at a time (1950s)
• Evolved to include libraries and multiple programs (later decades)
• GM created the first operating system (IBM 704, 1956)
• IBM started developing and distributing operating systems in the 1960s.
• Development of ON-Line System (NLS) at Stanford Research Institute was one of the first operating systems similar to today's desktop OS
• Microsoft developed MS-DOS and later bought and modified QDOS.
• Unix developed in mid-1960s (MIT, AT&T Bell Labs, General Electric)