Linux may have been causing USB disconnects

Post by tytso » Thu, Aug 22, 2013, 3:07 PM UTC

stinos wrote: post #61

dubcanada wrote: post #46

Earlier quoted context omitted.

That is a VERY general statement, most software engineers who do hardware stuff also know what takes to make it. You can't design a driver for a card without knowing everything about the card. And I'd say the same with hardware engineers. If you don't know how the software is going to run, how are you suppose to architect it. You can't make a piece of hardware without thinking about how the driver will work.

though I agree that it's probably too general of a statement, I'm more with raverbashing on this one: while now mainly doing software I have a strong hardware background and it's more often than not just baffling to see the approach of software-only engineers when having to code over the software/hardware border. Then again, maybe I only met some exceptions. I also have no idea if/how these topics are covered in a ty…

Post by uhno » Thu, Aug 22, 2013, 3:21 PM UTC

tytso wrote: post #71

stinos wrote: post #61

Earlier quoted context omitted.

though I agree that it's probably too general of a statement, I'm more with raverbashing on this one: while now mainly doing software I have a strong hardware background and it's more often than not just baffling to see the approach of software-only engineers when having to code over the software/hardware border. Then again, maybe I only met some exceptions. I also have no idea if/how these topics are covered in a ty…

Well, back when I was an MIT undergraduate, one of the core CS classes handed us a breadboard and a bunch of 74XX TTL chips, and we needed to construct a general register and stack computer from that. (We did get some PC boards that gave us a ALU and a UART that plugged into the breadboard, as well as the ability to program an EPROM to implement the firmware, but none of this "here's an Arduino or Rasberry Pi".) Mayb…

Post by mh- » Thu, Aug 22, 2013, 3:45 PM UTC

rustynails wrote: post #9

Now can someone fix the embarrassing network bug in Linux. You know, where if you access a link to a network, or access an open networked path after 255 seconds or so ... You receive a network error. It still begs belief that such a fundamental aspect of Linux is broken ... When I show Linux to newbies and this fault occurs (ie. 100% of the time), I simply say "Linux isn't perfect ..." But inside, I cringe... It occu…

    net.ipv4.tcp_keepalive_time
    net.ipv4.tcp_keepalive_probes
    net.ipv4.tcp_keepalive_intvl

Post by joosters » Thu, Aug 22, 2013, 4:41 PM UTC

danbee wrote: post #58

joosters wrote: post #43

Earlier quoted context omitted.

If you are connecting to a remote system, it could be NAT configured badly on your router. The router provided by my ISP (Virgin Media) is ruthless at closing idle TCP connections after only a few minutes. I'd see this with idle SSH logins being closed all the time. The solution (for me at least) was to ensure connections used TCP keepalives, and vastly decrease the keepalive times (various sysctl calls, I don't have…

Or just use a decent router and put the Virgin supplied thing in modem mode.

Post by varx » Thu, Aug 22, 2013, 5:01 PM UTC

nitrogen wrote: post #70

xradionut wrote: post #54

Earlier quoted context omitted.

I can't speak for kernel developers, but when you have complex and large codebase running on a huge variety of hardware, you will have some edge cases that are rare or difficult to debug. And I don't envy the folks that have to interface directly with hardware, I have enough fun in database land...

I'm an embedded software developer now doing some things with databases.... Give me hardware any day :-)