PicoScope buffer sizes are specified in kS (kilosamples), MS (megasamples) or GS (gigasamples). The makers of the memory chips that we use in PicoScope oscilloscopes usually state memory sizes as powers of 2, and we follow this convention in our specifications.  Here is what we actually mean by kS, MS and GS: Unit Power of 2 Decimal equivalent kS 210 1 024 samples MS 220 1 048 576 samples GS 230 1 073 741 824 samples As you can see, these numbers are close but not equal to one thousand, one million and one billion. So, if you buy an oscilloscope with a 1 MS buffer size, don't be surprised if you see a sample count slightly higher than 1 million in the PicoScope Properties panel. There are also many cases when the PicoScope 6 software gives you a sample count that is lower than the buffer size of your oscilloscope. This happens when PicoScope is in a repeat triggering mode and needs to use part of the memory for storing the next capture. It also happens when you have divided the memory into segments, and the number of segments that you have requested does not fit exactly into the available memory. To ensure that PicoScope 6 captures the greatest possible number of samples, set the Trigger control to Single and the Number of Samples control to a number greater than the buffer size of the oscilloscope.