Take the 2-minute tour ×  I have an embedded device that
connects to a PC using USB and enumerates as a USB serial port.
The device spits out approximately 30 megabytes of data over a
period of about 15 minutes.  My PC is running a Python script
using Pyserial to read this data and store it in memory. It
works fine.  I have given the script to three colleagues; one of
them also has no problem with it, but the other two find that
only about 40% of the data is received by the script.  All the
PCs are running Windows XP SP2 and all are of a similar hardware
spec. In all cases the serial device is connected directly into
the root hub, not via any external hubs or anything like that.
I tried connecting Hyperterminal and setting it to capture the
data to disk, again on my PC this works fine but on the two
other PCs it only collects ~40% of the data.  We all have the
same anti-virus stuff running (and no reason to believe it's
trying to scan this data as it comes in).  I am running out of
ideas as to why so much of