operating systems

Operating System

Software that abstracts low-level hardware details and manages I/O devices.

I/O Devices

Hardware used for input/output operations such as keyboards, printers, and storage.

Direct Memory Access (DMA)

A method allowing data to transfer directly between I/O devices and memory without CPU intervention.

Device Independence

The capability of the OS to provide a uniform interface regardless of the specific hardware.

Buffering

Temporarily storing data in memory to manage speed differences between I/O devices and CPUs.

Interrupts

Signals from hardware devices indicating that they require attention from the CPU.

Character Device

A type of I/O device that handles streams of characters, such as keyboards and mice.

Block Device

An I/O device that stores data in fixed-size blocks and can have multiple addresses, like hard drives and SSDs.

Memory-Mapped I/O

A method in which device registers are mapped into normal memory addresses.

Polling

The active process where the CPU waits and checks the device status registers.

Device Driver

Software that allows the operating system to communicate with hardware devices.

Power Management

The process of managing the power consumption of the OS and its components.

RAID (Redundant Array of Independent Disks)

A method of storing data on multiple disks to improve performance and fault tolerance.

Error Handling

The process of managing errors in I/O operations and presenting fault information to the user.

Synchronous I/O

I/O operations that block the process until the operation completes.

Asynchronous I/O

I/O operations that allow the process to continue execution while the data transfer occurs.

Deadlock

A situation where a set of processes is blocked because each process is waiting for a resource held by another process in the set.

Concurrency

The ability of multiple processes to run simultaneously and potentially interact with each other.

Coffman Conditions

Four conditions that must hold simultaneously for deadlock to occur: Mutual Exclusion, Hold and Wait, No Preemption, and Circular Wait.

Preemptable Resources

Resources that can be forcibly taken from a process without causing adverse effects.

Non-preemptable Resources

Resources that cannot be forcibly taken from a process without risk of errors.

Deadlock Detection

The process of identifying when a deadlock has occurred, often through resource-allocation graphs or matrix algorithms.

Resource Acquisition Process

The steps involved in using a resource: Request the resource, Use it, and Release it.

Banker’s Algorithm

An algorithm used for deadlock avoidance that determines whether resource requests can be fulfilled while ensuring the system remains in a safe state.

Starvation

A condition where a process is perpetually denied resources it needs to proceed, even though the system is not deadlocked.

Livelock

A situation where processes continuously change states in response to one another but do not make progress.