iMac shuts down itself in the middle of Safe Boot progress bar loading

WZZZ wrote:

Also I advise all boot drives be Zero erased before OS X is installed or cloned onto it to reduce bad sectors,

Totally unnecessary waste of time. This has been thoroughly bebunked. (But I don't wish to enter into an endless discussion on this here.)

Then I suggest you throughly research what hard drive manufacturers recommend before a operating system is reinstalled.

hendry17 wrote:

Hey Thank you guys for all your help, I managed to backup my important datas by installing OS on an external hard disk.

Now my imac is in service. Thank you once again

Great, glad it worked out. 😀

ds store wrote:

WZZZ wrote:

Also I advise all boot drives be Zero erased before OS X is installed or cloned onto it to reduce bad sectors,

Totally unnecessary waste of time. This has been thoroughly bebunked. (But I don't wish to enter into an endless discussion on this here.)

Then I suggest you throughly research what hard drive manufacturers recommend before a operating system is reinstalled.

Entering the search terms "zero fill new hard drive before using?" and "zero wipe (or zero erase) new hard drive before using?" and then searching site:wdc.com, seagate.com, hgst.com, hitachi.com, samsung.com, I am completely unable to find any recommendation from a drive manufacturer to do this. What, of course, I do find is the suggestion to reformat and then zero a problematic drive to identify and remove bad blocks. But this is not for a new drive, we already know this and I am not questioning this. Note: my remark that this was a waste of time came up in the context of the OP getting a new external drive. Go back and read again, and you will see that the OP was considering buying a new 3TB drive, and it was at this point that you made this recommendation, and it was this that I was referring to.

What I am able to find is the following from WD staff.

You shouldn't generally need to wipe a drive with zeros before using it.

http://community.wdc.com/t5/Other-Internal-Drives/Western-Digital-Scorpio-Blue-H aVING-IMAGING-PROBLEM-on-Dell/td-p/46970

So I suggest that YOU find such a recommendation from a drive manufacturer relating to a NEW drive.

Message was edited by: WZZZ

WZZZ wrote:

I do find is the suggestion to reformat and then zero a problematic drive to identify and remove bad blocks. But this is not for a new drive, we already know this and I am not questioning this. Note: my remark that this was a waste of time came up in the context of the OP getting a new external drive

You shouldn't generally need to wipe a drive with zeros before using it.

The person used "shoudn't generally need too" because there is a automatic system in place to map off bad sectors as they appear, thus moving the data to a spare sector. However it's not perfect and sectors can suddenly fail with the data on them and depending what and where it happens, it could just mean a loss of a small user file, or a preference file, or the program won't work or OS X won't work or worst, like corrupted GUID partiton table or EFI.

Alot of the problems we get here are because of a data failing on a bad sector, depending what is affected we recommend a restore method for that to save effort as it will most likely write to another portion of the drive, avoiding the problem sector.

When a person gets a new drive from the factory, it's got any number of bad sectors as all drives ship with them to various degrees.

Hard drives data retention on sectors actually gets better over time as you use it and it filters the failing ones, the zero erase speeds that process up so one has a stable hard drive right away, thus eliminates a lot of problems restoring this or that depending what sector fails where..

So by zero erasing a new drive (or even a older one) first instead of playing Russian roulete with one's data, one is using just plain zero's to check the entire drive before laying their valauble data on them.

Also if the drive is defective or suffered damage in some way, this zero gives the oppoprtunity to check the entire drive first before finding out later on. If one runs out of spare sectors, the zero erase will likely fail in a endless beachball, thus alerting the user of a defective drive and to get it replaced right away instead of losing everything later when their warranty runs out.

So generally one shouldn't need too zero erase a new drive, but it's much better if they do so as it results in a more stable machine.

Since the Disk Uiltity combined with driver firmware does all the work, the user just has to go do something else while the zero fill process is completed.

In the media industry with large audio and video files strecthing across many sectors, which it only takes one to fail to corrupt the entire file (expensive ones at that) seasoned IT pros in that field often zero erase all new drives, even using special software to make sure that there is no loss.

With users now downloading large media to hard drives, it pays to zero erase for them as well

There is also a performance boost, because if a drive has a failing sector, it takes the driver firmware several passes to read from the failing sector, resulting in beach balling effects and slow reads.

So it pays to zero for maximizing performance too. 🙂

I've heard all of this before, and seen it refuted. It probably doesn't hurt to write zeros to a new drive over any number of (many) hours, but it's very questionable whether it helps.

And you were the one who suggested I find confirmation of this from the different drive manufacturers. I couldn't find one scrap of it, but then I asked you to find it, since you were so certain it existed. What happened to that?

WZZZ wrote:

It probably doesn't hurt to write zeros to a new drive over any number of (many) hours, but it's very questionable whether it helps.

It's a few hours in computer time while the software works, or a few hours later in human time when something goes wrong.

I couldn't find one scrap of it, but then I asked you to find it, since you were so certain it existed. What happened to that?

Apprantly your search skills are not very good amd I'm almost wishing you slip on a patch of ice and fall on your behind. 😁

Writing zeros to a drive is recommended any time an operating system is to be reinstalled on a boot drive or whenever a blank drive is desired.

https://wdc.custhelp.com/app/answers/detail/a_id/1211/~/how-to-low-level-format- or-write-zeros-%28full-erase%29-to-a-wd-hard-drive-or-solid

Zero Fill writes zeros in each data sector for the complete capacity of the drive and cleans up most defects
....The advantage of this option is to discover and reallocate any defective (hard to read) sectors to good spares

http://knowledge.seagate.com/articles/en_US/FAQ/203931en

Game, set, match.

Your done. 😁

Not quite yet. And your manufacturer quotes don't come anywhere close to supporting the argument that a NEW drive should be zeroed. (And I will try to disregard your very obnoxious--not to mention childish--and uncallled for comment.) If you can't deal with the content, then please leave out the personal remarks. All of that just reflects very badly on you.

From Mike Bombich who just might know something about this you don't:

Yes, no application has access to those sectors once they are spared out.

In general, I don't encourage or discourage a "Zero all sectors" preparation of a new hard drive. It takes a long time, that's really the only downside. If you feel it is worthwhile, go for it. Sectors are generally spared out if a write operation to the sector fails, so pre-zeroing the drive will only save you from occasional "failed write" errors, it won't catch media failures that will occur after data is successfully written to a sector. For that reason, I don't see a lot of utility in doing it for new hard drives.

I recommend zeroing out all sectors primarily for hard drives that have shown more than a trivial amount of media errors. The zeroing will catch any other sections of media that are ready to fail upon write, and that will make the drive more responsive and more reliable for a future backup operation. I also consider it my "last chance" for the disk. If I see media errors after zeroing out a disk, I figure it's time to replace the disk. This is perhaps more a conservative position than other would take, but I really value my time and data :-)

I was advised to zero out HDDs before using them to ensure no data is ever written on physical bad blocks

I'm not sure I really agree with that advice. Sectors are spared out on write, so if a sector is bad, a write operation to the sector would fail and the OS would move on to the next sector. If a sector permits a write, and then a subsequent read fails, well, a zero-out operation isn't going to prevent or catch that scenario. I suppose the only benefit that has is that every sector gets at least one write operation. If a sector was going to fail on the second write, then there's some benefit. I don't know what the probabilities are for a sector failure occurring on the second write and not the first, but I can't imagine it is high enough to warrant the time spent in a zero-out sectors initialization.

I'm an academic, though, so I'd love to see an argument in favor of zeroing out sectors on a new disk.

Mike

http://help.bombich.com/discussions/questions/2689-zero-out

Writing zeros to a drive is recommended any time an operating system is to be reinstalled on a boot drive or whenever a blank drive is desired.

I thought we had already agreed we are talking about NEW drive preparation. And your other quote says nothing about NEW drive preparation either. I'm tired of this ******* contest with you. If you want to zero your new drives, no one is stopping you, but I don't think you should be making that a universal recommendation, especially in a User Tip. Over and out

Message was edited by: WZZZ

Not over and out. Just out.