If two concurrent threads are scheduled by the OS to run on one single-core processor, you may get concurrency but not parallelism. Parallelism is possible on multi-core, multi-processor or distributed systems. Concurrent needs to share resources whereas Parallel each process has their own resources at their disposal.
How the code is written differently, that depends on a lot of things.
Jan Vladimir Mostert
Idea Incubator
If two concurrent threads are scheduled by the OS to run on one single-core processor, you may get concurrency but not parallelism. Parallelism is possible on multi-core, multi-processor or distributed systems. Concurrent needs to share resources whereas Parallel each process has their own resources at their disposal.
How the code is written differently, that depends on a lot of things.