Skip navigation

Once I was at an ATM machine, of course to get some money for a gift to a friend of mine. I keyed in the amount & was waiting for money. The machine took a while, printed the receipt, gave out the card. Yes that’s all. I got no money but a receipt saying that the machine gave this amount of money & that amount of money left in the account. I lost my tongue except to murmur Faaaark!. I pushed my card back in checked the balance in account & the machine was very happy to say that I’ve just lost this amount of money.
The gift I was planning to by was intended to be a wedding gift & my friend was/is not the kind which is gonna marry again ;). I went to the bank, talked to the pretty girl & my story didn’t amaze her in any mean. Hmmm…That’s something to think about.

Facing that inconvenience, my mind kept thinking of the very thing a lot, I mean about the technical stuff. Why the machine don’t handle that very little but so very important event? What’s the system run on an ATM machine? is it an embedded system? does it run GNU/Linux? :) hell a lot to think.

After few days I went on a long tour with two of my geek friends & the topic ATM took priority at a time. And my friends provided me with these info. There are ATM machines which runs Microsoft Windows XP :D (in Sri Lanka) & earlier days it was OS2, according to Such. Kunchana has seen windows XP booting on an ATM after a power down. [Wikipedia confirms Such and Kunchana :)]

In thinking deep about ATM machines I made some assumptions in my mind.

1) The machine keeps track of the money using some kind of a hardware mechanism or someone adds money & update records on the machine. So that the machine keeps track of the amount remaining. If this is the case it’s only a matter of a software modification to compare the remaining amount and requested amount to stay away from hassles.

2) Since there was no evidence to backup above assumption, I happen to think that ATMs don’t keep track of the amount of money they have. So in order to avoid problem I faced, the machines have to have a mechanism to keep track of remaining amount of money and of course compare the remaining and requested amounts.

appendage (17/12/09) :
This was quite an old writeup I never had chance to post till now. This is totally black boxed thinking without looking up Internet for more details how an ATM works. The incident I mentioned happened at Commercial Bank Nugegoda. I got the money back in my account in few days (The bank fixed it manually, I guess). I’ve heard few other cases like this but never again happened to me. And also Things should be changed and these problems should be ironed out by now. Anyway Off to Look up “How ATM works” :D

PS: And the friend who got married was geekaholic :D . The incident occurred  someday around 20/06/08, the wedding day.


  1. when speaking about ATM machines, I always getting this same thought “why the Fuck is this money making machines are not getting robbed?” May be you can remember my plan to dig a tunnel to rob the s**** ATM(like in bank job)!:P

  2. I have seen Windows booting in ATMs, Fatal Exception messages and also the infamous BSOD. :) Now that I think of I’m a pretty heavy user of ATM cards. I heard some run WinCE too.

  3. It happened to me with the Commercial Bank ATM at Crescat. As I was using my card in UK I was pissed. When I called the bank they knew that the ATM had run out of money to dispense. They then informed me that an automated system had already debited the money I never got back to my account. It took about seven days. I was pissed off. Now I just use only HSBC ATM’s when in SL.
    I wonder if this is a problem with combank ATM’s only?

  4. Dushi ATM’s are robbed all the time. Recently in UK they actually pulled one in a shop out with a chain, loaded it into the truck and got away with it!

  5. From what I know ATMs know when their cash box is empty. Also they should know exact count that is remaining.

    They are usually loaded with number of different cartridges containing fixed number of different kinds of bills.

    When you fill the thing you know how much it is filled with. When you withdraw money it know how much you took out (otherwise how does it give the amount you requested).

    The problem is the mechanical things in the machine has to be very robust in order to handle both new and old bills. When they get old they tend to jam. just like old printers.

    Most ATMs have built in fail safe and fault tolerant mechanisms in please against these kind of things. For example if a bill inside the ATM is damaged/old and can cause a jam it will not be processed through the ATM. Instead it will be redirected in to a separate box/cartridge. But sometimes all those mechanisms fail but the software continue processing your transaction without noticing it.

  6. This happened to me on saturday the 27 of February, 2010. The atm started to count my money than just stopped. Momentarily flashed a screen saying “ATM Unavailable” then went back to the screen saying”insert card to begin transaction”. The money was deducted from account but I didn’t recieve any. Only bank drive thru was opened and they told me they didn’t know what to and that this has never happened. Now I have to take off of work Monday to see if this can be straightened out. Good thing is that no one else was able to get any money out after me so I hope that this will help me in my claim. Hopefully it jammed up and my last transaction will be easy to find.

  7. the atm machine ate my money
    as i was taking it out

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: