Question hdd badblock interference and dvd burn

[BradtheRad]

I used to run chkdsk on hard drives when their capacity was a mere few hundred MB. And floppy drives too because many failed after sitting in a drawer for years.

These days with GB capacity, a run takes so long that I don't bother.
Furthermore my PC computers are laptops. The hard drives are little 2.5 inch size.
After intense computer use I can feel the area getting hot where the hard drive is located (I think).

Therefore it seems risky to check every byte on an entire disk. I do not perform it when I run the Windows utility that checks a hard disk.

 

[betwixt]

Why are you fixated on bad sectors (or blocks) they are very rare after the drive has left the factory, most computers will never see one in their lifetime and even if one did appear, there are several protection mechanisms in place to either alert you or bypass the problem.

Again, if there are bad areas on the disk, they will not be used. You are more likely to wear the disk out prematurely by running chkdsk every time than gain any benefit from doing it.

If chkdsk finds 'fragments' of files or unallocated clusters it does not indicate a problem with the disk and it should not cause you any problems, they are just entries in the file allocation table that are no longer pointing to any valid data. That is a problem almost exclusive to Windows which you will not find a solution for.

Brian.

 

[John rodrigues]

Do you have an automatic function in the operating system or HDD that isolates any defective sectors in the HDD preventing files from being saved to it? chkdsk is manual and I don't always run it

 

[betwixt]

As I keep saying - bad blocks are extremely rare AFTER the HDD has left the factory. To become bad requires that the disk becomes physically damaged and in normal use that is highly unlikely. To damage the media you would probably have to drop the drive maybe more than 50cm on to a hard surface while it was in operation. Bad blocks sometimes occur because of uneven oxide coating on the disk platter, a manufacturing defect, but the low level format identifies it and that area is marked as 'do not use'.

Putting it in perspective, the drive I am using right now to write this has 537,234,768 blocks and zero defects after five years of almost continuous use.

Whether or not the OS automatically notes any bad blocks depends on what OS you use. I use 'ext4' format with Linux as OS and I believe it does automatically store any bad blocks it discovers, other OS and formats may not. It has never found one though!

Brian.

 

[John rodrigues]

I use system between Windows XP 32bit and windows 10 64bit Does the HDD or Windows have an automatic option that separates the defective sectors so that nothing is saved in these sectors?

 

[betwixt]

No idea. I stopped using Windows and switched to a reliable operating system many years ago. Perhaps others can answer your question.

Brian.

 

[John rodrigues]

is the allocation of the bad sectors of the hdd to prevent data from being saved in these sectors something only from chkdsk and not from hdd? only manually?

 

[unbuildpain]

is the allocation of the bad sectors of the hdd to prevent data from being saved in these sectors something only from chkdsk and not from hdd? only manually?

I think all storage mediums, including HDDs come with some amount of extra storage space which is inaccessible to even OS, this is provided so that if there is a bad sector, the HDD can remap the data in the bad sector to that extra storage space, so I think HDDs also have some function which regularly checks for bad sectors and copies that data to some other place.

 

[betwixt]

The bad block data is not stored in a user accessible part of the disk. Some parts of the disk are 'reserved' and unless you are using the manufacturers diagnostic programs or low-level formatting you can't access them. In other words they are not files, you can't see them and you can't manually edit them but they are there on a hidden part of the disk.

Depending on the drive firmware, it MAY be possible for it to add to the bad block list if it detects one but please understand that a bad block is one that has a physical defect, not one that contains corrupted information. The drive/OS will not let you use a bad block, it is considered to be unsuitable for storing any information because of a physical defect and it can never be repaired.

Chkdsk will scan the disk for corrupted blocks (or sectors) and report ones where the CRC recorded in the block does not match the one it calculates from the data in that block. It does not mean the disk is permanently bad, it means it contains data that seems to be corrupt. Usually, writing new data to the same block will work without any problems. chkdsk will also find and report orphan blocks, they are ones that are perfectly good but have somehow lost their entries in the file allocation table. It will usually copy the data from the block to a file then repair the allocation table entry.

It would be useful for you to learn how file allocation tables work, it would make it easier for you to understand the link between the name and details of a file with where it is physically stored on the disk surface.

Brian.

 

[John rodrigues]

If someone does not know the manual command chkdsk and that person's HDD has bad sectors then will the downloaded and transferred files be written to those bad sectors of the HDD?

 

[ads-ee]

if i don't manually run chkdsk not repair will the bad sectors receive the files and corrupt them? chkdsk is the only protection to prevent data from being written to the HDD in this case?

This has been repeatedly explained to you.

Don't bother runninng chkdsk unless the OS tells you to run it because it found bad sectors. If your OS has tools to look at the SMART data that is probably more helpful than randomly or even regularly running chkdsk on a HDD. I've never run across a drive that failed without some indication in the SMART data before it started having errors.

the drive electronics calculates a CRC from the bit stream and also stores that in the block. It then reads it back, re-calculating the CRC from the data and comparing it with the CRC it saved. If they are different it will tell you there is an error straight away. The chances of bad data being written and a matching bad CRC being checked is extremely unlikely, I'm no mathematician but the probability is trillions to one.

HDD, don't use a CRC on blocks of data they use reed solomon encoding so the can correct errors during reads. If I still remember correctly SMART actually uses that RS ECC data to help determine if there are sectors that are beginning to exhibit abnormal number of ECC corrections on the data read. If you read up on HDD magnetic technology you'll be somewhat amazed we can rely on such a unreliable medium for storage it's all the coding that goes into sticking those bits on the drive that gives it any sort of reliability.

 

[John rodrigues]

without running chkdsk does the smart present in hdd solve and block the bad sectors from receiving files?

 

[ads-ee]

If someone does not know the manual command chkdsk and that person's HDD has bad sectors then will the downloaded and transferred files be written to those bad sectors of the HDD?

If you have unrecognized bad sectors then anything written to those sectors will be corrupted due to a bad write operation. I'm pretty sure Windows does not perform a verify on written data, that is why if you download something you should hopefully have the md5 or sha1 sum so that you can verify the download is correct. Running it on the file will compute the sum again and if any corrupted reads occur due to a bad sector the sum won't match and then it might be worth doing a chkdsk as you may have found a bad sector that isn't marked.

Over the many decades of using computers, I've only personally had a few HDDs fail. Two occured on work machines that were running software that would basically hammer on the drive for 7-10 hours as it would continually update somatabase stored on the drive (this was back when RAM was severely limited) and once when I banged my laptop hard when it was accessing the drive. Once the heads hit the platter you have "magnetic dust" particles inside the drive and things become intermittent to say the least. Since then I haven't had one HDD fail or even exhibit errors for probably close to 20 years or more. Now during that time I've seen lots of software corruption after windows updates that cause the PC to have problems. The last time it happened I reformatted the drive and there wasn't any new bad sectors and installed linux on the laptop, haven't had any issues since. The drive on it is a hybrid drive that is easily 15 years old and still works without errors.

--- Updated Aug 28, 2020 ---

without running chkdsk does the smart present in hdd solve and block the bad sectors from receiving files?

SMART monitors a drive for errors and ECC being performed during drive reads. Statistics are computed on those reads to determine if a drive is beginning to exhibit too many read errors that need to be corrected. This has nothing to do with whether you write to a given sector or not.

CHKDSK examines a drive to determine if there are any errors and optionally depending on the command line switches used can attempt to read a bad sector and move it to a good sector before marking it as bad.

 

[John rodrigues]

Many people are unaware of chkdsk so these people are going to have problems with bad sectors not allocated and separated?

 

[ads-ee]

Many people are unaware of chkdsk so these people are going to have problems with bad sectors not allocated and separated?

Probably they don't know about CHKDSK because they haven't had a problem.

Usually if you have file system corruption and file read errors the OS will report that you should run CHKDSK to find and fix the problems. At least the last time I had to run it on a WIndows 7 Pro machine it found a few file system issues (no bad sectors) due to a crash that required a hard reset to reboot the PC. Haven't seen anything like that on my Windows 10 PCs yet. The system actually suggested that CHKDSK be run as it was booting and I think it even offered to do it by hitting space or return or that hit any key request. Don't remember the exact message it's been 8+ years when it last happened.g

Please answer my question...
Why are you so obsessed about data integrity and data retention? You are exhibiting signs of paranoia about it based on what you've posted so far.

 

[unbuildpain]

Probably they don't know about CHKDSK because they haven't had a problem.

Usually if you have file system corruption and file read errors the OS will report that you should run CHKDSK to find and fix the problems. At least the last time I had to run it on a WIndows 7 Pro machine it found a few file system issues (no bad sectors) due to a crash that required a hard reset to reboot the PC. Haven't seen anything like that on my Windows 10 PCs yet. The system actually suggested that CHKDSK be run as it was booting and I think it even offered to do it by hitting space or return or that hit any key request. Don't remember the exact message it's been 8+ years when it last happened.g

I think the bootup CHKDSK message actually says, press any key to skip the scan disk, not initiate it. It automatically runs the scan disk after expiry of 5 seconds after it showed that message.

Please answer my question...
Why are you so obsessed about data integrity and data retention? You are exhibiting signs of paranoia about it based on what you've posted so far.

Maybe it is meant to alert one of the users to make backups, check their SSD, HDD health.

 

[John rodrigues]

Doesn't SMART do the automatic function of allocating defective sectors and preventing files from being saved in these sectors? chkdsk is manual sometimes I forget to do chkdsk before downloading important files

 

[c_mitra]

Windows run CHKDSK at boot time (but you can disable that). The hard disk errors are taken care of by the controller and the driver software. If you have written a program and you want to read and write a file, you need not worry about cylinders, sectors, CRC etc because they are taken care of by the disk controller and the driver software. The driver software presents an uniform interface to the user program irrespective of the actual hardware (disk type, format etc etc). For user, you see only files on disk and not hardware sectors, cylinders etc. If you use a low level format that is incompatible with the driver (and the controller), the disk may become unusable. So, avoid low level formatting unless you are sure (use the manufacturer provided software).

 

[John rodrigues]

disk controller = HDD card, software driver = HDD firmware ???

 

[ads-ee]

John, make an effort to look stuff up on google occasionally, as of now you have no google-fu padawan...Train harder you must.
Searching for HDD smart wiki has the first result...

https://en.wikipedia.org/wiki/S.M.A.R.T.

It looks like the most recent versions of SMART now include some preventative measures, which is probably why I've never seen any issues on my last few computer HDDs. I read the original SMART specifications a long time ago when they introduce it and it did not have any ability to fix problems.

disk controller = HDD card, software driver = HDD firmware ???

Definitions I like to use with others:

Firmware - embedded software that is run on the hardware and manipulates the hardware directly. e.g. set bit 2 of register 5 to 1. It also provides some standard interface to a connector (e.g. SATA, PCIe, etc) which exposes whatever features are available on the device. It is usually located in ROM (read only memory).

Software driver - software typically written by the manufacturer (who writes the embedded firmware) that will run on a OS that directly translates the exposed interface of the connector and the features of the device into a set of API calls for the OS to use.

Definitions vary by whomever creates them....try these google search results.
software driver definition
firmware definition