COE128 Exam - 1 Flashcards
Is a program that manages the computer hardware
Operating System
It provides a basis for application programs and acts as an intermediary between the computer user and the computer hardware
Operating System
Examples of Operating Systems
Mac OS
IOS
Android OS
Linux
Windows
Types of OS
Batch OS
Time Sharing OS
Distributed OS
Network OS
Real Time OS
MultiProgramming/Tasking OS
Functions of OS
- It is an interface between the User and the Hardware
- Allocation of Resources
- Management of Memory, Security, ect.
Goals of OS
- Convenience
- Efficiency
- Both
Its function is to synchronize access to the memory
Memory Controller
The initial program that runs when a computer is powered up or rebooted.
Bootstrap Program
Refers to the process of starting up a computer or initializing a computer.
Booting
The occurrence of an event is usually signaled by an ________ from hardware or software.
Interrupt
During the ____________, the computer’s hardware is initialized, and the operating system’s kernel is loaded into memory. Once the kernel is loaded, it takes over control of the system and starts executing the necessary system services and drivers to bring the computer to a fully operational state.
Booting Process
Hardware may trigger an _________ at any time by sending a signal to the CPU, usually by the ways of the system bus.
Interrupt
Software may trigger an interrupt by executing a special operation called ________.
System Call
The fixed location usually contains the starting address where the ____________ is located.
Service Routine
Storage-device Hierarchy
Register ↔ Cache ↔ Main Memory ↔ Electronic Disk ↔ Magnetic Disk ↔ Optical Disk ↔ Magnetic Tapes
Memory that last only while the power is on (and thus would be lost after a restart).
Volatile Memory
Types of Computer Memory
Volatile Memory and Non-Volatile Memory
Is a type of computer memory that can retain stored information even after power is removed.
Non-Volatile Memory
Why is it not possible to store program and data to the main memory?
- It is too small to store all needed programs and data permanently
- It is volatile storage device that loses its contents when power is turned off.
Able to hold large quantities of data permanently.
Secondary Memory
An extension to the main memory
Secondary Memory
Types of Computer System
- Single Processor System
- Multi Processor System
- Clustered System
One main CPU capable of executing a general purpose instruction set, including instructions from user processes.
Single Processor System
Also known as parallel systems or tightly coupled system
Multiprocessor System
Has two or more processors in close communication, sharing the computer bus and sometimes clock, memory and peripheral devices.
Multiprocessor System
Advantages of Multiprocessor Systems
- Increase throughput
- Economy of Scale
- Increase Reliability
Types of Multiprocessor Systems
Symmetric Multiprocessing and Asymmetric Multiprocessing
It gather together multiple CPUs to accomplish computational work.
Clustered Systems
It is composed of two or more individual systems coupled together.
Clustered Systems
It provides high availability and can be structured asymmetrically or symetrically.
Clustered Systems
Two things that every OS must be capable of doing.
- Multiprogramming
- Time Sharing (Multitasking)
The capability of running multiple programs by the CPU.
Multiprogramming
Increases the CPU utilization by organizing jobs (code and data) so that the CPU always has one to execute.
Multiprogramming
Provides an environment in which the various system resources are utilized effectively, but they do not provide for user interaction with the computer system.
Multiprogrammed System
The CPU executes multiple jobs by switching among them.
Time Sharing (Multitasking)
Switches occur so frequently that the user can interact with each program while it is running.
Time Sharing (Multitasking)
It requires an interactive (or hands-on) computer system, which provides direct communication between the user and the system.
Time Sharing (Multitasking)
A ________ allows many users to share the computer simultaneously.
Time-Shared Operating System
Uses CPU scheduling and multiprogramming to provide each user with a small portion of the time-share computer.
Time Sharing (Multitasking)
A program loaded into the memory and is executed is called _______.
Process
9 Operating System Services
- User Interface
- Program Execution
- I/O Operations
- File System Manipulation
- Communication
- Error Detection
- Resource Allocation
- Accounting
- Protection and Security
Human to computer interaction and communication in a device.
User Interface
Two Types of User Interface
CLI - Command Line Interface
GUI - Graphical User Interface
Run the program in the computer.
Program Execution
Transfer data to or from a computer.
I/O Operation
The OS controls how the files in your system are manipulated or managed.
File System Manipulation
It controls the permission that is given to certain programs or users for the access of certain files.
File System Manipulation
Process of exchanging information between different components of an OS.
Communications
When error occur, your system must not break down completely and it should not just seize your computing ability completely.
Error Detection
The OS should allocate the required resource to the processes which are asking for those resources.
Resource Allocation
The OS must allocate the resources in an efficient way such that all the processes get the resources that they need.
Resource Allocation
Having usage of statistics can be valuable for researchers who wish to reconfigure the systems or to improve the computing services.
Accounting
When several different processes are executing at the same time, they should not interfere with each other’s operation. And it involves ensuring that all access to system resources are controlled.
Protection and Security
Provides an interface to the services made available by an Operating System.
System Calls
Two modes of operation on which a program can execute.
- User Mode
- Kernel Mode
- Does not have direct access to memory, to the hardware and other resources.
- Safe Mode
User Mode
- Has direct access to memory, hardware and other resources.
- Privileged Mode
Kernel Mode
When a program is switching from user mode to kernel mode (vice versa) that is known as _________.
Context Switching
It is the programmatic way in which a computer program requests a service from the kernel of the OS.
System Call
end, abort
Process Control
5 Types of System Call
- Process Control
- Device Control
- File Manipulation
- Information Maintainance
- Communications
load, execute
Process Control
create process, terminate process
Process Control
get process attributes, set process attributes
Process Control
wait for time
Process Control
wait event, signal event
Process Control
allocate and free memory
Process Control
create file, delete file
File Manipulation
open, close
File Manipulation
read, write, reposition
File Manipulation
get file attributes, set files attributes
File Manipulation
request device, release device
Device Management
get device attributes, set device attributes
Device Management
logically attach or detach devices
Device Management
get time or date , set time or date
Information Maintenance
get system data, set system data
Information Maintenance
get process, file, or device attributes
Information Maintenance
set process, file, or device attributes
Information Maintenance
create, delete communication connection
Communications
send, receive messages
Communications
transfer status information
Communications
attach or detach remote devices
Communications
Also known as system utilities, provide convenient environment for program development and execution.
System Programs
6 Categories of System Programs
- File Management
- File Modification
- Status Information
- Programming-language Support
- Program Loading and Execution
- Communication
Create, Delete, Copy, Rename, Print, Dump, List, and generally manipulate file and directions.
File Management
Ask the system for:
- Date, Time
- Amount of available memory or disk space
- Number of users
- Detailed performance
- Logging and debugging information
Status Information
Several text editors may be available to create and modify the content of files stored on disk or other storage device.
File Modification
- Compilers
- Assemblers
- Debuggers
- Interpreters
for common programming languages
Programming-language Support
Once a program is assembled or compiled, it must be loaded into memory to be executed.
Program Loading and Execution
The system may provide:
- Absolute loaders
- Relocatable loaders
- Linkage editors
- Overlay loaders
These programs provide the mechanism for:
- Creating virtual connections among processes, users, and computer systems.
- Allowing users to send messages to one another’s screens
-To browse Web pages
- To send electronic-mail messages
- To log in remotely, and to transfer files from one machine to another .
Communications
The system should be convenient to use, easy to learn and to use, reliable, safe, and fast.
User Requirements (User Goals)
The system should be easy to design, implement, and maintain; and it should be flexible, reliable, error free, and efficient.
Designer/ Engineer Requirements (System Goals)
Determines how to do something.
Mechanism
Determines what will be done.
Policies
Advantages of writing in high level languages.
- The code can be written faster
- It is more compact
- It is easier to understand
- It is easier to port
The fundamental idea behind a ____________ is to abstract the hardware or a single computer into several different execution environment, thereby creating the illusion that each separate execution environment is running its own private computer.
Virtual Machines
Two Modes of Virtual Machine
Virtual user mode
Virtual kernel mode
Advantages of Virtual Machines
- Isolation
- Resource Sharing
- Convenience
- Security
- Compatibility
- Software Development and Testing
VMs provide a high degree of isolation between the guest operating system (OS) and the host OS.
Isolation
VMs can efficiently share physical resources, such as CPU, RAM, and storage, with the host and other VMs.
Resource Sharing
Can simultaneously run multiple operating systems on a single physical machine
Convenience
VMs are often considered more secure because any issue or malware in one VM are isolated from other VMs and the host OS.
Security
VMs allow you to run operating systems that may not be compatible with the host hardware.
Compatibility
Developers can create isolated environments to test different software configurations or conduct cross-platform testing.
Software Development and Testing
Examples of Virtual Machine Software
Oracle VirtualBox
VMware Workstation
Microsoft Hyper-V
KMV(Kernel-based Virtual Machine)
