Who has worked with magnetic stripe cards and what can be done with them?

Question

linux

The point is exactly this. At the dawn of his IT mini-career, he worked in a very small company selling, installing and supporting cash equipment (POS-s, cash registers, scanners, PLU-scales and other heresy from all sorts of Pyaterochkas). New Panasonic POS-terminals came to us and, separately from them, authorization card readers (for waiters). Still, it became interesting - I connected the reader to a PC, opened a notepad and swiped a small network grocery store card .. Voila. The card number and percentage discount are shown. Spent with a credit card - the card number and some service information are shown (the card without a chip).
And non-trivial questions have ripened:
1. How often are chain stores where discounts are written directly on the card?
2. Has anyone tried to overwrite the contents of a magnetic tape
3. And purely in theory, if I write down all the information from the credit card on a blank card, is there a chance that it will work? (There was once an article on Habré about guys who wanted to make a universal card, on which you can record several tracks of information for different stores, so as not to carry a whole heap)
*All information is purely for educational purposes.
**Sorry for #linux, #microsoftwindows)) couldn't find adequate tags for the question
ADDENDUM TO POST

Magnetic Stripe Cards - Encode/Decode

Answer 1

Discounts on the card are written for the client, the card is identified by the information recorded on it.
On the map, 3 stripes are the physical division of the map. The most running 2 is the middle lane. Banks can use all lanes. Different symbols are used for the beginning and end of each strip (Google help). Information is usually presented in numbers (there is a special standard for this). Cards come with different information density (Hi-co and regular).
I work with magnetic cards (software from www.ucs.ru) - for recording I use MSR206 (recording card reader) - I wrote my additional software for it, which worked with the base of the main software. There is of course a demo program that comes with drivers. I often rewrite the contents of old bank cards to the one I need (for use in software).
Of course, you can copy cards, but the store may refuse to accept a blank card or require a passport.
As for many tracks, I doubt it ... although if there is not a lot of information, then in the high-density mode, information can be recorded sequentially with the corresponding signs of the beginning and end of the strip. You can easily write 3 cards for one, and if the identifier is short, then up to 6 cards will fit (maybe more).

Answer 2

Smells like carding :)