HP server PSU

7 July 2020

The guy with the Swiss accent covered using server PSUs as a cheap 12V power supply. I had seen other computer PSUs converted to use outside of the computers they were intended for but this one tempted me to go for it since it has all it's power as one 12V output and it can drive 62.5A on that output (there are also 1200W models, but 750W seemed like enough for me). And for less than £15. So I got three.

They've got a few part/model numbers: Regulatory Model No. HSTNS-PL18, Generic Part No. 506821-001, Part No. 506822-001 and Spare Part No. 511778-001.

First thing I did was power one up and poke at it with a meter. That confirmed that the always on 12V line was where I was expecting it, +12V on pin 37 and GND on pin 30. This always on connection is good for 30W.

I then soldered a switch between pins 33 and 36. Closing that switch powered on the main 12V output. And some more poking with a meter and some loads confirmed that pin 34 gave an on/off status of a little over 3V and pin 34 gave a voltage that varied with load. This looked about right for the 20A per V I was expecting. That confirmed all the details of the pinout that I cared about.

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The pstree options I want

10 June 2020

I use pstree every so often to investigate how something was called or what something has spawned. I almost always want the same behaviour: show me parents and children of this process, with PIDs and usernames. To get that I should use pstree -sup <PID>.

Now I should know where to look when I can't remember what the options I want are.

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Network effect

2 April 2018

As Warren Ellis recently mentioned: once upon a time if your kink was one in a million you needed to be in a fairly big city to find a single digit number of people who might be on the same page.

Finding them was a non-trivial exercise.

Those days are past (but recent enough that I can remember them).

The internet now connects 3.something billion people. A one in a million kink lumps you in with a few thousand people. And they're only a Google search away.

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Save chrome eating battery life

2 January 2018

I seem to collect chrome tabs. I usually have a few dozen open, often many more if I haven't cleaned them out for a while. Once upon a time reboots would clear them out but these days I reopen the previous session when I boot so tabs don't go away unless I actually tell them to. Lots of them do stuff in the background so chrome ends up using a decent chunk of CPU time. It is almost always at the top of the list in powertop.

Most of the time I don't care about this. If my computer is plugged in then it's fine. When I'm running on battery though I care a lot more. Then when I'm doing something that I don't need the web I put chrome to sleep with killall -STOP chrome and then when I want it back: killall -CONT chrome. Bind those two commands to keys and I can stop and start chrome as needed, and when I don't need it it doesn't get to eat my precious battery life.

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I want a new camera

19 October 2017

I think it's about time I got a new camera. I've thought this for a while, but keep baulking at the price of getting something that would be a decent improvement over what I currently have.

What I have

I have a Sony A55 at the moment. The internet tells me it was released in 2010, and I think I got mine between Christmas and New Year that year. On the lens side I've a Sigma 18-250 super zoom and a 50mm prime that cover most of what I do and I still have the 18-70 kit zoom from my A200 that I sometimes use as I have close focus filters that fit it and let it get really up close to stuff.

What I want

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