The "green card" is a patient's most prized possession in hospital or outpatients. It may be torn, worn and dirty, but a patient will almost never lose the card. On it is written their personal details, hospital number, and a short discharge summary from each time they've been in hospital.
It's much easier looking at a green card than searching through a computer program for admission details or discharge summaries. It also has all of their outpatient encounters written on neatly torn pieces of paper stapled to the green card. As soon as somebody goes to outpatients, the nurses do a blood pressure, temperature and weight - more consistently than your average family GP.
Patients are also in charge of their own X-rays, which they collect as soon as they are done and carry to outpatient on metal drying frames. They keep them safe and neat and bring them along to every medical encounter from then on.
Perhaps it is because they don't have much other paperwork for things to get lost in, but patients are much better at looking after their medical records than we would be. It may be 'primitive' keeping everything on a single green card, but the system works. And I like it.