Posts by Sachin Tolay

@Sachin Tolay

Sachin Tolay

I am here to share everything I know about computer systems: from the internals ...
Vancouver Joined June 2025
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Posts by Sachin Tolay

Sachin Tolay in Tutorials 3 min read
When a program performs I/O → like reading from a file or socket → two key questions arise: Does the program stop and wait for the data, or continue running? Blocking vs Non-blocking IO Does the program keep checking for the result, or get notified...
Sachin Tolay in Tutorials 3 min read
In our earlier deep dive into Direct Memory Access DMAhttps://coderlegion.com/3952/understanding-direct-memory-access-dma-how-data-moves-efficiently-between-storage-memory, we explored how data can bypass the CPU to move efficiently between storage a...
Sachin Tolay in Tutorials 6 min read
When you open a file in your program, it seems like you can read or change any byte you want. But in reality, your storage device doesn’t work with single bytes. Instead, HDDs and SSDs read and write data in larger chunks, called blocks or pages, whi...
Sachin Tolay in Tutorials 3 min read
Transferring data between Storage and Memory can slow down a computer if the CPU has to manage every step. Direct Memory Access DMA is a mechanism that lets a dedicated controller take over this job, freeing up the CPU and making data movement faster...
Sachin Tolay in Articles 8 min read
Modern multi-core CPUs depend on caches to accelerate memory access and improve performance. However, when multiple cores cache the same memory address, maintaining a consistent view of memory across all cores and main memory known as cache coherence...
Sachin Tolay in Tutorials 5 min read
If you’ve ever clicked “Sign in with Google” or “Connect with Facebook” on a website or app, you’ve interacted with technologies called OAuth and OpenID Connect OIDC. These two standards form the backbone of secure authentication and authorization on...
Sachin Tolay in Tutorials 5 min read
Whether you’re building a simple web app or a large distributed system, users don’t just expect it to work → they want it to be fast, always available, secure, and to run smoothly without unexpected interruptions. These expectations are captured in ...
Sachin Tolay in Tutorials 8 min read
Modern software performance is deeply influenced by how efficiently memory is accessed. The full story of memory access latency involves multiple layers → from CPU caches to virtual memory translation, and finally to physical DRAM. This article expla...
Sachin Tolay in Tutorials 5 min read
Modern software performance depends heavily on how efficiently memory is accessed, and not just on raw CPU speed. Sequential memory access tends to be much faster than random access, and understanding why requires a deeper look inside the memory subs...
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