QUIZ 1 Flashcards
What is an Operating System?
A program that acts as an intermediary between a computer user and the computer hardware.
What are the goals of an Operating System?
- Execute user programs
- Make the computer system easier and more convenient to use
- Use the computer hardware in an efficient manner
What are the four (4) components of a computer system structure?
- Hardware
- Operating system
- Application programs
- Users
What do application programs do?
Application programs define the ways in which the system resources are used to solve computing problems for users.
In what way is an OS is a resource allocator?
- It manages all resources (CPU, memory, disk, peripherals, etc.)
- It decides between conflicting requests for efficient and fair resource use.
What is the one program running at all times on the computer?
The kernel.
What is volatile memory?
Memory that is lost when power is cut.
What is a bootstrap program and what does it do?
- A program that Initializes all aspects of the system.
- It is typically stored in ROM or EPROM, generally known as firmware
- It is loaded at power-up or reboot
- It searches for a bootable OS kernel on hard disks, USB drives, and even over the network.
What is RAM?
- Random Access Memory
- Random, as opposed to sequential (like tape)
- It is the main memory: the only large storage media that the CPU can access directly
- Typically volatile meaning it is lost as soon as computer is shut down
What does secondary storage do?
- extends main memory & provides large nonvolatile storage capacity
What is a hard disk?
- rigid metal or glass platters covered with magnetic recording material
- includes a disk controller, which determines the logical interaction between the device and the computer
What do device drivers do?
- Manages I/O for each device
- Provides uniform interface between controller and kernel
What is the relationship between main memory and caching?
- Caching involves copying information into faster storage system; main memory can be viewed as a cache for secondary storage.
What is caching?
- Happens when information in use copied from slower to faster storage temporarily
- faster storage (cache) checked first to determine if information is there
- If it is, information used directly from the cache (fast)
- If not, data copied to cache and used there
- Cache is always smaller than the storage being cached
What is the I/O subsystem responsible for?
- Memory management of I/O including buffering, caching, spooling
- General device-driver interface
- Device drivers for specific hardware
What is buffering?
Storing data temporarily while it is being transferred.
What is spooling?
- The overlapping of output of one job with input of other jobs.
- Management of how devices receive data, to avoid overload (e.g. with print jobs).
What is a thin client?
- A network computer where all data is stored on and processes executed on central server, while I/O is redirected to user terminal.
What is distributed computing?
- Collection of separate, possibly heterogeneous, systems networked together.
from Wikipedia:
Distributed computing is a field of computer science that studies distributed systems. A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. The components interact with one another in order to achieve a common goal.
What is virtualization?
- An OS natively compiled for CPU, running guest OSes that also natively compiled
- Guests interact directly with CPU
What is emulation?
- When source CPU architecture different from target architecture (i.e. PowerPC to Intel x86)
- Requires Interpretation (i.e. When computer language not compiled to native code)
- Generally slowest method
What services does an OS provide that are helpful to the user?
- User interface
- Program execution
- I/O operations
- File-system manipulation
- Communications
- Error detection
- Resource allocation
What OS functions exist to ensure the efficient operation of the system itself?
- Resource allocation
- Accounting
- Protection and security
What is the difference between a program and a process?
- A program is passive entity stored on disk (executable file)
- A process is active, a process is a program in execution
- A program becomes process when executable file loaded into memory
What are the essential parts of a Process?
- The program code, also called text section
- Current activity including program counter, processor registers
- Stack containing temporary data (e.g. function parameters, return addresses, local variables)
- Data section containing global variables
- Heap containing memory dynamically allocated during run time
What is Reentrant code?
A programming routine/process that multiple applications can share simultaneously.
What it is a CPU?
- Central Processing Unit
- the electronic circuitry within a computer that performs arithmetic and logic instructions
- where processes are executed
What is symmetric multiprocessing?
In a multi-CPU, or multi-core system: each processor can perform all tasks.
What is a register?
A memory location within the actual CPU that works at very fast speeds. It stores instructions which await to be decoded or executed.
