For the past five years, I’ve been working in a semiconductor clean room. I’m interested in the connections between manufacturing and computer science. One that stands out to me is the importance of concurrency control throughout the fab (factory).

The fab has a multitude of interconnected monitors, machines (aka “tools”), servers, and computer programs. Multiple employees may interact with a tool or lot remotely at the same time. To prevent errors in processing, it is important to keep the sequence of events synchronized.

In my OSU classes, I have used thread management libraries in Python and C++ for concurrency control. When a sensitive transaction takes place, one thread will lock the data store (Amarasinghe, et al). Other threads cannot access the data until the first thread has released it (Amarasinghe, et al).

Some programs in the fab use something like optimistic concurrency, where updates are allowed, but fail on save if someone else made a change in the meantime (Vickers). If a technician puts a lot on hold while an operator is in the middle of logging lot data, the software will show an error and prevent data submission.

However, some programs do not have concurrency checks in place. For instance, separate software is used to evaluate data and track lots. After data entry, an operator might need to wait a few seconds before updating the lot status in the tracking software. The data software doesn’t always evaluate the data and flag the lot immediately.

My fab needs some improvements in concurrency control. For instance, locking lots or tools from operators while waiting for data to be uploaded and evaluated.

Works Cited
Amarasinghe, S., et al. “Reading 23: Locks and Synchronization” Software Construction. MIT, Fall 2015, web.mit.edu/6.005/www/fa15/classes/23-locks/#reading_23_locks_and_synchronization. Accessed 11 Jan 2024.
This work is licensed under CC BY-SA 4.0.

Vickers, A., et al. “Handling Concurrency Conflicts.” Microsoft Learn, 5 July 2023, learn.microsoft.com/en-us/ef/core/saving/concurrency?tabs=data-annotations.
Accessed 11 Jan 2024.