Yet Another Tech Poster

Day 2/7 of Java Concurrency - Semaphores We all know about locks for mutual exclusion. But what if we want to allow N threads in at once? Semaphores solve this exact problem - the api is quite simple - you initialize with a number of "permits" Semaphore semaphore = new Semaphore(n, true); The key methods - acquire() - takes a permit (blocks if none available) release() - returns a permit the boolean parameter is for fairness - true = fair (FIFO) false = no fairness guarentee (but faster!) Any thread can release a permit. Unlike a lock, the thread that acquires doesn't have to be the one that releases - allowing signaling between threads.

One interesting observation I’ve noticed is a lot of top founders did oddly strong at math from a young age.

Delve, a YC-backed compliance startup that raised $32 million, has been accused of systematically faking SOC 2, ISO 27001, HIPAA, and GDPR compliance reports for hundreds of clients. According to a detailed Substack investigation by DeepDelver, a leaked Google spreadsheet containing links to hundreds of confidential draft audit reports revealed that Delve generates auditor conclusions before any auditor reviews evidence, uses the same template across 99.8% of reports, and relies on Indian certification mills operating through empty US shells instead of the "US-based CPA firms" they advertise. Here's the breakdown: > 493 out of 494 leaked SOC 2 reports allegedly contain identical boilerplate text, including the same grammatical errors and nonsensical sentences, with only a company name, logo, org chart, and signature swapped in > Auditor conclusions and test procedures are reportedly pre-written in draft reports before clients even provide their company description, which would violate AICPA independence rules requiring auditors to independently design tests and form conclusions > All 259 Type II reports claim zero security incidents, zero personnel changes, zero customer terminations, and zero cyber incidents during the observation period, with identical "unable to test" conclusions across every client > Delve's "US-based auditors" are actually Accorp and Gradient, described as Indian certification mills operating through US shell entities. 99%+ of clients reportedly went through one of these two firms over the past 6 months > The platform allegedly publishes fully populated trust pages claiming vulnerability scanning, pentesting, and data recovery simulations before any compliance work has been done > Delve pre-fabricates board meeting minutes, risk assessments, security incident simulations, and employee evidence that clients can adopt with a single click, according to the author > Most "integrations" are just containers for manual screenshots with no actual API connections. The author describes the platform as a "SOC 2 template pack with a thin SaaS wrapper" > When the leak was exposed, CEO Karun Kaushik emailed clients calling the allegations "falsified claims" from an "AI-generated email" and stated no sensitive data was accessed, while the reports themselves contained private signatures and confidential architecture diagrams > Companies relying on these reports could face criminal liability under HIPAA and fines up to 4% of global revenue under GDPR for compliance violations they believed were resolved > When clients threaten to leave, Delve reportedly pairs them with an external vCISO for manual off-platform work, which the author argues proves their own platform can't deliver real compliance > Delve's sales price dropped from $15,000 to $6,000 with ISO 27001 and a penetration test thrown in when a client mentioned considering a competitor

Day 3/7 of Java Concurrency - Compare and set - the secret sauce behind lock free data structures Lock free data structures manage to avoid race conditions without using any locks at all - how is this even possible? Enter compareAndSet, a method exposed by AtomicReference. The API is very straightforward - ref.compareAndSet(expected, newValue) -> if the current value is expected, then it sets it to newValue, otherwise if another thread updated it - we get a return false. No waiting, no blocking. The key pattern that makes this useful is running it in a loop, we keep comparing and setting in a loop till the thread eventually gets one return true, and we exit! Look at this lock free implementation of a stack that can handle concurrent reads and writes!

Fixed a slow DB query for a client, dropping the p99 time by 99.9% (250ms -> 0.24ms) The cause? Everyone's favorite: a missing index What a beautiful graph 📉🚀

If I can do 16k LOC per day across 3 different projects (including one open source one you can see yourself) then I think almost any technical CEO CTO pair at YC will That's the bar now

AI is making CEOs delusional