Vigneesh Manoharan

Tag: debugging

  • Karat Interview Experience (2026) – Questions, Process & Tips

    Karat interview experience can be quite different from traditional interviews. In this article, I’ll share my Karat interview experience, including the questions asked, process, and tips to crack it.

    I had a Karat interview scheduled for a leading bank as online screening round. This is the first time I’m attending an interview that’s being conducted by a third party for a company.

    Got naturally interested on this process, I wanted to know more about how this interview is taken and started searching online. Guess what, I couldn’t find a single video explaining about the interview pattern and all I could find was interview experiences of people who attended interviews to work for Karat.

    So I decided to write this blog in the hope that this could be of help for someone to better prepare mentally for a Karat interview.

    Disclaimer: Their interview pattern might not be the same for all companies and the companies themselves also could have partnered with them to frame the question areas.

    P.S: Not revealing any questions I encountered to maintain ethics

    So following is their interview pattern

    • Introduction – 5 minutes
    • Technical questions – 10 minutes
    • Coding and debugging – 45 minutes

    Introduction

    This section is about both ways. The interviewer from Karat introduces about themselves and also explains about the interview pattern, which, you’re reading here, wink wink.

    And then you introduce about yourself and the request would be to do that in under 60 seconds.

    Technical Questions

    So this part of the interview is questions on basics and intermediate concepts in your programming language of choice and depending on the role you’re opting for.

    This section of the interview is a pretty much comfortable zone and you can complete this if you’re decently prepared.

    Coding and Debugging

    Now this is where things get interesting. This is not your regular, tell a program and you code it kind of a round. And this round tests how quick you’re with debugging and problem solving by assessing how many coding questions you’re able to solve in these 45 minutes.

    It typically starts with debugging. You will be presented with a code and the corresponding test cases already written and the question for you would be to identify why one of the test cases fail and what’s the issue with the code.

    And the intensity will get increased slowly asking to write logic for a test case that’s already written.

    This is how this round goes and this is where I stopped so I don’t have further visibility on whether they will actually ask you to write a code from scratch along with test cases.

    What I Liked

    Was how unbiased the questions were and also how it focused more on your problem solving and critical thinking side rather than if you remember the syntax.

    And the interviewer. OMG, they were really calm and composed and gave clarity right before the start of the interview on how the rounds will be.

    They will also support you midway of the coding round if you need any guidance.

    What I didn’t like

    Was the lack of guidance online about the interview pattern which is not the case anymore, wink wink.

    I hope this post might have given you some insights on what to expect from your Karat interview that’s scheduled real soon and how prepared you should be both technically and mentally.

    Go get it. Good day to you 🫡.

  • Debugging Wireless Mouse Lag with USB-C Hub — A Small Issue That Turned Into a Good Learning

    Recently I ran into a strange issue with my setup that looked simple at first, but ended up teaching me a lot about wireless interference, USB hubs, and how small hardware changes can affect system behavior.

    I use a Mac with an external monitor connected through a USB-C HDMI hub, along with a wireless mouse that uses a 2.4 GHz USB receiver. For a long time everything worked fine with my office laptop, but after switching adapters I started noticing random mouse lag and stuttering.

    At first it looked like a minor problem, but the behavior was inconsistent, which made it interesting to debug.

    The problem

    The mouse pointer would randomly lag or stutter, especially when the receiver was connected through the HDMI dongle.

    Things I noticed:

    • Mouse works fine when plugged directly into laptop
    • Lag appears when using USB-C HDMI hub
    • Issue happens only sometimes
    • Dell adapter worked perfectly before
    • New adapters (even slightly expensive ones) showed lag

    This suggested the mouse itself was not the problem.

    Initial assumptions

    My first guesses were:

    • Bad HDMI hub
    • Cheap adapter issue
    • macOS driver problem
    • Mouse hardware problem

    So I tried:

    • Different HDMI dongles
    • Different USB ports
    • Different mouse positions

    The issue still appeared.

    That meant the problem was probably environmental, not just hardware quality.

    Key observation — Dell adapter never had this problem

    With my work laptop I was using a Dell DA20 USB-C adapter, and I never faced any lag.

    Differences between that setup and my current one:

    • Dell adapter was plastic body
    • New adapters were metal body
    • Router was placed on my desk
    • Mouse receiver connected to hub instead of laptop

    This made me suspect wireless interference.

    Understanding 2.4 GHz interference

    Most wireless mice use 2.4 GHz receivers.

    Wi-Fi routers also use:

    • 2.4 GHz
    • 5 GHz

    USB 3.0 ports are also known to emit noise around 2.4 GHz.

    When all of these are close together, interference can happen.

    In my case, I had:

    • Router on the desk
    • USB-C hub with HDMI + USB3
    • Metal adapter body
    • Mouse receiver plugged into hub

    This is almost the perfect setup for signal interference.

    Why metal adapters can make it worse

    Metal hubs are not bad by themselves, but cheaper ones may have poor shielding.

    Possible issues:

    • RF signal reflection
    • USB3 noise leakage
    • Poor grounding
    • Weak isolation between ports

    Enterprise adapters like Dell docks usually have better internal design, which explains why the Dell adapter worked fine.

    Attempted fix — USB extension cable

    One common solution suggested online is using a USB extension cable to move the receiver away from the hub.

    Reason:

    • Moves receiver away from noise source
    • Reduces interference from USB3 / HDMI
    • Improves signal strength

    I ordered one to test this.

    Final fix — moving the Wi-Fi router

    Before the extension cable arrived, I moved my Wi-Fi router back to its original place in the hall instead of keeping it on my desk.

    Immediately, the mouse lag disappeared.

    No adapter change.
    No mouse change.
    No software change.

    Just moving the router fixed the issue.

    This confirmed the root cause was wireless interference.

    What I learned from this

    This small issue reinforced a few important debugging lessons:

    1. Change one variable at a time
    2. Compare with a known good setup
    3. Environment matters as much as hardware
    4. Expensive accessories don’t always fix the problem
    5. Wireless interference is very real in modern setups

    It also reminded me that real-world engineering problems are often about systems interacting, not just one component failing.

    Final setup that worked

    • Router moved away from desk
    • USB receiver not blocked by hub
    • Using existing HDMI dongle
    • No need for expensive adapter

    Simple fix, but good learning.

    Conclusion

    This started as a minor mouse lag issue, but turned into a useful reminder about RF interference, USB3 noise, and systematic debugging.

    Sometimes the best solution is not buying new hardware, but understanding how the current setup behaves.

    And those small debugging experiences often teach more than big projects.