Disk Utility: for bad blocks on hard disks, are seven overwrites any more effective than a single pass of zeros?

Question

In this topic I'm not interested in security or data remanence (for such things we can turn to e.g. Wilders Security Forums).
I'm interested solely in best practice approaches to dealing with bad blocks on hard disks.
I read potentially conflicting information. Examples:
… 7-way write (not just zero all, it does NOT do a reliable safe job mapping out bad blocks) …
— https://discussions.apple.com/message/8191915#8191915 (2008-09-29)
… In theory zero all might find weak or bad blocks but there are better tools …
— https://discussions.apple.com/message/11199777#11199777 (2010-03-09)
… substitution will happen on the first re-write with Zeroes. More passes just takes longer.
— https://discussions.apple.com/message/12414270#12414270 (2010-10-12)
For bad block purposes alone I can't imagine seven overwrites being any more effective than a single pass of zeros.
Please, can anyone elaborate?
Anecdotally, I did find that a Disk Utility single pass of zeros seemed to make good (good enough for a particular purpose) a disk that was previously unreliable (a disk drive that had been dropped).

Answer 1

@MrHoffman
As well pointed your answers are, you are not answering the original question, and regarding consumer device hard drives your answers are missleading.
Consumer device hard drives ONLY remap a bad sector on write. That means regardless how many spare capacity the drive has, it will NEVER remap the sector. That means you ALWAYS have a bad file containing a bad sector.
In other words YOU would throw away an otherwise fully functional drive. That might be reasonable in a big enterprise where it is cheaper to replace the drive and let the RAID system take care of it.
However on an iMac or MacBook (Pro) an ordinary user can not replace the drive himself, so on top of the drive costs he has to pay the repair bill (for a drive that likely STILL is in perfect shape, except for the one 'not yet' remaped bad block)
You simply miss the point that the drive can have still one million good reserve blocks, but will never remap the affected block in a particular email or particular song or particular calendar. So as soon as the file affected is READ the machine hangs, all other processes more or less hang at the same moment they try to perform I/O because the process trying to read the bad block is blocking in the kernal. This happens regardless how many free reserve blocks you have, as the bad block never gets reallocated, unless it is written to it. And your email program wont rewrite an email that is 4 years old for you ... because it is not programmed to realize a certain file needs to be rewritten to get rid of a bad block.
@Graham Perrin
You are similar stubborn in not realizing that your original question is awnsered.
A bad block gets remapped on write.
So obviously it happens at the first write.
How do you come to the strange idea that writing several times makes a difference? How do you come to the strange idea that the bytes you write make a difference? Suppose block 1234 is bad. And the blocks 100,000,000 to 100,000,999 are reserve blocks. When you write '********' to block 1234 the hard drive (firmware) will remap it to e.g. 100,000,101. All subsequent writes will go to the same NEW block. So why do you ask if doing it several times will 'improve' this? After all the awnsers here you should have realized: your question makes no sense as soon as you have understood how remapping works (is supposed to work). And no: it does not matter if you write a sequence od zeros, of '0's or of '1's or of 1s or of your social security number or just 'help me I'm hold prisoner in a software forum'.
I would try to find a software that finds which file is affected, then try to read the bad block until you in fact have read it (that works surprisngly often but may take any time from a few mins to hours) ... in other words you need a software that tries to read the file and copies it completely, so even the bad block is read (hopefully) successful. Then write the whole data to a new file and delete the old one (deleting will free the bad block and ar some later time something will be written there and cause a remap).
Writing zeros into the bad block basically only helps if you don't care that the affected file is corrupted afterwards. E.g. in case of a movie the player might crash after trying to display the affected area. E.g. if you know the affected file is a text file, it would make more sense to write a bunch of '-' signs, as they are readable while zero bytes are not (a text file is not supposed to contain zero bytes)
Hope that helped ;)