I wrote thousands of lines of C code on an Atari Portfolio, which was my portable development machine for a few years .. it had Turbo C on it, booted up real fast, and was all I needed to make tweaks in between visiting customers - I wrote database recovery software with it .. It was always very fun to break it out at the conference table upon arrival, make the needed changes (magic numbers), do a quick build and then plop the .com onto the target machine for processing ..

Still have those machines somewhere, great little devices.