The True Hackers

A quote of the day for me comes from a digest of the Gemini project software history (

“I’m beginning to learn things about the Gemini memory I wish I had known in the 1960s. For example, after many divide instructions were executed in a row (I don’t know how many), the memory cores heated up and you would get the wrong answer in the accumulator. This problem was controlled by inserting a no-op instruction between the divides, thus keeping the cores cool enough to always give the right answer. Wow!”

Wow! indeed..!

Testing equipment at Hackerspace Kraków

Hackerspace Kraków got two nice analog oscilloscopes with 20MHz bandwidth from our sponsor. Initial tests using the built-in 1kHz square wave generators with provided probes showed a gloomy picture of bumpy squares that could have been caused by Who Knows What, and the picture below shows the best we could get by tuning the probes.


Yesterday I brought my cheap Voltcraft/Hantek/Tekway DSO to see what’s going on. Turns out the main problem were our probes – using the ones from my oscilloscope we got nice squares using all three signal generators available!



However, testing revealed that test signals provided by generators in HS oscillosopes are not 1kHz squares anymore:



And this one is quite disturbing as well – given the same signal source – I hope it’s just the matter of using two completely different probes!