Ryan's Journal

Not something I normally write about, but maybe it will save somebody a headache.

Star Market has been offering self-checkout lines in locations near me somewhere in the past year or so. One swipes bar codes and bags groceries while following directions on a touchscreen. While convenient and generally quick, occasionally a poorly written piece of code will produce a condition where the controller will tell you you've added an extra item to the bag; when you remove it, it will tell you you've removed an already bagged item and then tell you to re-bag it. The cycle cannot be broken except by an employee with the proper credentials.

I thought this happed at random until I finally figured it out: if you've scanned a savings card and the item you just scanned has savings on it, you have to let the controller finish telling you how much you've saved before you bag the item.

I don't understand why the programmer thought it necessary to wait until the speech code finished playing before moving to the 'please bag' code; one might fairly assume that the speech portion is basically fluff since blind customers can't use the touchscreen system and give it far lower priority. First set the 'please bag' flag, then play the voice, then check if the item's been bagged.

I wonder what hardware and language these things use.