The 8008 was: Blinky lights WAS: The SR71 Blackbird was designed ENTIRELYwith slide rules 665
The 8008 was: Blinky lights WAS: The SR71 Blackbird was designed ENTIRELYwith slide rules 666
Woah there a minute -- please include a modicum of reality. In the first place -- not any schmoe with your account data can initiate an ACH-EFT...
The way it works here, or at least every bank that's issued me a debit card, is there is an "available balance" that is maintained separately from the normal balance. On top of that, there's often per-day and per-transaction limits on charges that are also consulted.
When a merchant charges a card, the amount authorized is deducted from the "available balance". If the transaction actually "posts" later, the final amount (which is sometimes different, as in restaurants and bars) is deducted from your true balance. If the transaction does not post after N days, the amount is returned to your "available balance". N varies by bank but is often 3 or 7.
Unfortunately, it is typically impossible to dispute or even investigate authorizations before they post. This means some merchant can (often accidentally) draw down your "available balance" to zero for N days. This happened to me once in college when I visited NYC, leaving me broke with no means to return home. Thankfully, a manager at Citibank took pity on me and allowed me to cash a check from a rural Illinois bank with a Texas ID, but if it didn't take 7+ days for interstate checks to clear back then, it would have bounced due to the screwy debit card authorizations.
-- Stephen Sprunk "Those people who think they know everything CCIE #3723 are a great annoyance to those of us who do." K5SSS --Isaac Asimov
The 8008 was: Blinky lights WAS: The SR71 Blackbird was designed ENTIRELYwith slide rules 667
First -- banks have been settling drafts electronically for roughly fifty years -- the only thing new about ACH is that now it is done in real time instead of moving boxes...