intro to Operating Systems Flashcards
A computers functions and features can be broken down into 3 basic tasks:
- input
- output
- processing
provides a method for users to interact with the computer
user interface
a file system is a method by which OS stores and organizes files and manages access to the file
storage management
a program that’s loaded into memory and run by the CPU
process
a type of process that runs in the background
service
the OS must determine if sufficient memory exists to load an application and where in memory it should be loaded
memory/ I/O managment
OS’s used on the business systems to provide methods for securing access to resources
security and resource protection
the heart of the OS and runs with the highest priority
kernel
can only execute a single process at a time
single task OS
a computing device designed for a specific task and uses a single-tasking OS
embedded system
quickly switches between all the processes that are loaded into the memory and scheduled to run
multi-tasking OS
the OS gives the CPU control to process and waits for it to terminate or enter a waiting state: If a program doesn’t give control back to OS; may hog the CPU until it does
cooperative multitasking
the OS is in control of the computer at all times
preemptive multitasking
allows only one user at a time to interact with the OS user interface, start processes, make system, configurative changes, and interact directly with the file system
single user OS
Allows multiple users to sign in to it, start and stop processes, interact with user interface, and access local file system
multi-user OS
designed to provide a convenient user interface and run applications in a home or business environment with reasonable performance ie. clients/ normal ppl
general purpose OS
designed to process inputs and produce outputs in s very specific and repeatable amount of time ie. Robot lines, fedEX sorting facilities,etc.
real-time OS (RTOS)
Most Oss can be classified as?
- client
- server
- standalone
run applications requested by a user and request data from network serves as necessary
client OS
to share network resources and provide network services to clients.
ie. macOS Server, Windows Server: Usually come with DHCP server, a DNS Server, a file server protocol, a Web server, and perhaps a directory service like Microsoft’s active directory
server OS
the ability of a system to recover from hardware or software failure
fault tolerance
the ability of two or more servers to act as one
supported by which OS?
clustering
server OS
two or more servers alternate in taking client requests
load sharing cluster
components such as hard disks, memory, or even processors so if a computer fails , a new component can be swapped (hardware)
hot swapping
components so that more storage, RAM, or processors can be added while the system is running
hot-adding
most standalone Os’s run on?
embedded systems ie.traffic cams
a series of steps performed by every computing device that starts with power to the CPU and other hardware components and ends with a running system ready to perform work.
boot procedure
is a program code that is stored on computer hardware in non-volatile memory and is responsible for performing diagnostic tests and booting the OS
firmware
is memory that maintains its contents when no power is applied to the system
Non-Volatile Memory
program that locates and then loads the bootloader program
bootstrap
responsible for loading the initial process that makes up the OS
bootloader
are firmware programs that play a part in the boot process
The basic input/output system (BIOS) and unified Extensible Firmware Interface (UEFI)
Performs tests at startup, such as memory and hardware component tests
power on self test (POST)
BIOS configuration is stored in?
a complementary metal oxide semiconductor
(CMOS) memory chip
a program that is loaded into memory and executed by the CPU, can be a user application, an OS service, or even the Kernel
process
a CPU mode in which a process has unrestricted access to the computer hardware and has access to privileged CPU instructions
kernel mode
a CPU mode in which the process can only access memory locations allocated to it by the OS, must ask OS to access I/O devices on its behalf and can’t execute privileged CPU instructions
user mode
when a process is created it is assigned a ____ which allows other processes to communicate with it and the user to manage it
Process ID
an identifier for a file that contains all the information the file system needs to locate and access the file
file handle
- Memory is managed by a ______ that runs in kernel mode
dedicated memory manager
usually a kernel mode process that accesses hardware devices directly on behalf of user mode processes or other kernel mode processes
device driver
a process where the OS checks each device one after the other in a round-robin fashion to see if it requires attention, because of shortcomings, most systems use interrupts
polling
A signal, usually generated by an I?O device, that alerts the CPU and OS that a device needs attention
interrupt
pins on a CPU
interrupt request lines (IRQ)
when the CPU detects the IRQ line, it stops what it is doing, determines the source of the interrupt, and starts the execution of the ___, also known as the interrupt handler
interrupt service routine (ISR)
to prevent unnecessary interruptions, ISRs turn off interrupts of equal or lower priority
interrupt masking
A certain class of interrupts and cannot be turned off
non-maskable interrupts (NMI)
verifies that an account trying to access a system is valid and has provided valid credentials
authentication
verifies that an authenticated account has permission to perform an action on a system
Authorization
Scheduling computer processes and managing resources are?
key tasks of the OS Kernel
