Isolation
The mechanisms that prevent one workload from interfering with another by enforcing boundaries over memory, CPU, files, and privileges.
Definition
Isolation is the property (and set of mechanisms) that prevents one workload from interfering with another by enforcing boundaries over memory, CPU time, files, devices, and privileges.
In practice, isolation is what makes “run many programs on one machine” safe enough to be useful.
Where isolation comes from
Isolation is enforced primarily by the kernel using mechanisms like:
- separate virtual address spaces between processes
- privilege separation (user mode vs kernel mode)
- access control over kernel-managed resources (files, sockets, devices)
Isolation isn’t “no impact”
Isolation doesn’t mean programs can’t affect each other at all. They still share finite resources:
- contention for CPU, memory, disk, network
- noisy-neighbor effects under load
Isolation means those effects are mediated and bounded, not that they disappear.
How it shows up in real systems
Containers and sandboxes are additional layers that use kernel primitives to tighten isolation boundaries. VMs go further by isolating at the level of an entire guest OS.