Need clarification about Bad Sectors

[mr_raghav]

Hi, I purchased a PC in June 2015. It is used by my friends as well who doesn't really bothered to shutdown the PC properly. I have Kaspersky Internet Security updated regularly. I have Windows 7 & 8 dual boot with 7 as default.

Recently, my PC was unable to boot. After removing and replacing SATA power & data cables, it was able to boot. It was unable to boot into Windows 7. So, I booted into Windows 8 and ran CHKDSK on few drives.

It gave me a message, "The disk does not have enough space to replace bad clusters....." on two or three drives. I didn't completed the CHKDSK as it was taking long time with the above error message. Upon restart, the PC didn't boot again.

Even though the HDD has lot of free space, it was throwing above error message that it doesn't have free space. After googling, I came to know that the free space of HDD is different from the space that used to replace the bad sectors/clusters (whatever). I have little knowledge about PC hardware but not much about HDD.

I just wanted to know,

1) How much space is allocated for replacing bad sectors and how long it is useful. How to know how much space we have and/or whether we have enough space to replace bad sectors.?

2) What the causes for bad sectors and how to avoid them.? Does improper shutdown and virus creates bad sectors.? My HDD is not even 1 year old. I have few HDDs which are nearly 7 years and they are still working even though not perfectly.

3) I heard about HDD Regenerator to repair bad sectors. What exactly it does.? What are the free alternatives to it.?

4) Does Zero'ing HDD recreate space for replacing bad sectors. Which is the best software for making all zero's. (I heard about KillDisk but never used it.)

5) What is low level formatting and how to do it.?

6) What is the difference of making all zeroes, low level formatting and using HDD Regenator kind of software.

Waiting for clarification from the experts.

Thank you.

 

[drtweak]

1) it varies between drive to drive. there is no exact number but the bigger the drive the more space it has.

2) Bad sectors are physical errors on the drive platters. If the PC hasn't been moved around or dropped or anything like that then it is just normal failure. A lot like how a car can break down for any reason.

3) HDD Regenerator attemps to repair or read the data form the bad sectors. There are 3 things to look for on SMART status of a hard drive. Pending sector counts, uncorrectable sector counts, and reallocated sector counts.

Pending Sectors are sectors it is trying to recover data from. The hard drive will try and try to get the data. If it get the data it then becomes a Reallocated Sector count. These are the sectors the hard drive have set aside for bad sectors. A Uncorrectable sector is a sector that it was not able to recover the data from and flag it as bad and you can't use it or that data anymore. HDD Regenerator goes in and forces the drive to try to read the data again.

4) Zeroing can help at times. if you were to backup your data and do a 3 pass wipe which is what i like to do and you compare the before and after SMART status sometimes the drive gets better. sometimes it stays the same. and sometimes it gets worse.

Honestly in my opinion if it is failing, replace it, wipe the drive, and then toss it.

5) low level formatting and Zeroing out is the same. A low level format is the same as doing a full format or writing zeros to all the drives. A Quick format only erases the file indexes making them as free space even though there could be data there still.

6) answers are above.

If you can get back into the PC great. Download Crystal Disk info in my signature and see how bad it is. If you can't turn on the PC plug them into another PC that works and then run the program. To me it sounds like you need to backup your data and just get a new drive.