The Worst Employee Ever

This is archived from the original post still on the Internet Archive. I was bowled over by the lack of awareness here so I just had to archive it. There are several images in the original blog post that I haven't backed up. However, I did pull down the real whopper - an excerpt from the termination letter - and put that up.



I was employed by Hudson River Trading (HRT).

Zappa vs Mangum

Zappa and Mangum[1] are Python libraries that parse events from Amazon's API Gateway and feed them into a Python WSGI or ASGI application. This allows you to put API Gateway in front of a Lambda runtime, have Lambda execute the service requests that come in through API Gateway, and code your service logic in any Python web framework.

Disk caching in the year 2020

In the previous blog post I went over the design of storage systems and how they protect themselves from data loss in the face of disk failure or unclean shutdowns. If you’re putting together the hardware yourself modern Linux systems and modern hardware give you endless cost, performance and durability tradeoffs for whatever system you want. But 2020 also gives us the cloud, and storage systems in the cloud whose durability far exceeds whatever you could build yourself.

Durability in the year 2020

It is the year 2020 and we still don’t have great answers to data durability in the face of unclean shutdowns. Unclean shutdowns are things like power outages, system faults and unlucky kernel panics and preventing data loss when they happen is a hard problem. I’m going to talk through a few ways these can cause data loss in this blog post but you can probably come up with new ones on your own - exotic failures that no system will ever handle correctly. In the year 2020, the conventional wisdom is still true. Always take backups, and RAID is no substitute for backups.