No systems can provide fault-free guarantees, including distributed systems. However, failures in distributed systems are independent. It means only a subset of processes fail at once. We can exploit this feature and provide some degree of fault tolerance. The problem is, fault tolerance makes everything else much more difficult...

In a distributed system, eventual consistency provides a weak guarantee that data updates will be reflected in all nodes eventually. However, the downside of eventual consistency is that clients could potentially observe awkward intermediate states..

Normally, having consistent event ordering in a distributed system is hard because we have no common clock. Since we don’t have a common clock to measure with, we rely on logical properties of time in the absence of clock. Here we use causality replation between events..

Mutual exclusion is a common term appearing frequently in computer sciences. In essence, it’s a mechanism of concurrency control allowing exclusive access to some resource (or “critical region”). Token passing is an algorithm for distributed mutual exclusion and will be our focus in this post..

Before we jump into how to write specifications in a distributed setting, we first define what a specification is. I take the definition from the magnificent Ken McMillan: a specification is a statement..

This paper by UTNS lab appeared in NSDI 2021. It presents a data-analytics framework that decouples intermediate data from computations..

This paper by Nadeen appeared in MLSys 2021. It presents an in-network aggregation framework called PANAMA for distributed ML training tasks. PANAMA has two components: (1) an in-network hardware accelerator with support for floating-point gradient aggregation; (2) a domain-specific load-balancing and congestion control protocol..

Memcached is a high-performance, distributed caching system. Although application-neutral, it’s most commonly used to speed up dynamic Web applications by alleviating database load. Memcached is used on LiveJournal, Slashdot, Wikipedia and other high-traffic sites..

This post assumes the user has already setup two separate repositories: a private repository for Hugo source files, and a public repository for GitHub Pages...

This is a comprehensive summary over how Grover’s quantum search algorithm works. It explains the three major steps involved in Grover’s iteration..