Understanding Starvation and Aging in Operating Systems: Causes and Solutions

Starvation and Aging are two common problems in Operating systems (OS) that can occur when multiple processes or threads compete for resources, such as CPU time, memory, or I/O devices.

Starving

"Starving" occurs when a process or resource is not given enough priority or resources to function properly. This can result in the process being unable to complete its tasks or even crashing.

Example

For example, imagine a computer running multiple applications at once, and one of the applications is a video editing software that requires a lot of processing power. If the computer's operating system does not allocate enough CPU resources to the video editing software, it may start to "starve" and become unresponsive, which could result in the user having to force close the application.

Aging

On the other hand, "Aging" is a problem that occurs when a process or resource is given too much priority or resources for an extended period of time, causing other processes or resources to suffer.

Example

For instance, consider a situation where a single process is given high priority and is allowed to use a large amount of system resources, such as CPU or memory. This can cause other processes that require those resources to slow down or crash, ultimately affecting the overall performance of the system.

Examples of Starvation & Aging and Solutions

CPU Scheduling

Suppose that a scheduler assigns a high-priority process to the CPU repeatedly, without ever allowing low-priority processes to execute. In this case, the low-priority processes may experience starvation.

To fix this, the scheduler can implement a technique called Aging. This involves gradually increasing the priority of lower-priority processes as they wait, to ensure that they eventually get a chance to run.

Resource Allocation

Consider a scenario where multiple processes compete for a shared resource, such as a printer or a disk drive. If one or more processes constantly monopolize the resource, other processes may suffer from starvation.

To address this problem, the operating system can implement a technique called Fair Share Scheduling, which ensures that each process gets a fair share of the resource. This can be achieved by allocating the resource to each process for a fixed amount of time, before releasing it for other processes to use.

Memory Management

Suppose that a process requests a large amount of memory, but the available memory is insufficient, leading to the process being blocked. If other processes continue to request memory, the blocked process may suffer from starvation.

To prevent this, the operating system can implement a technique called Virtual Memory, which allows each process to use a portion of the hard disk as if it were main memory. This ensures that even if the physical memory is insufficient, the process can continue to execute without being blocked, preventing starvation from occurring.

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