I have a DELL PRECISION M4400 running Windows 7 Professional.
Recently, the laptop started freezing and would go to sleep and would not be able to wake up unless a hard reset was given.
I downloaded and ran the DELL diagnostics from the DELL website which indicated a HDD failure. It was recommended to replace the HDD. I got the following (truncated) report (SMART) for the 320GB HDD.

HDDScan Drive Test Report 
Model: WDC WD3200BEKT-75PVMT0
Firmware: 01.01A01
Serial: WD-WXL1A91U2336
LBA: 625142448

Report By: HDDScan for Windows version 3.3
Report Date: 8/21/2015 1:08:33 AM

Open Disk
Test : RD-Read

Block start at 2428416 time 55ms
Block start at 14633472 time 51ms
Bad block found, start LBA : 19194880
Block start at 26177024 time 261ms
Block start at 41292800 time 58ms
Bad block found, start LBA : 46550528
Block start at 46551296 time 73ms
Block start at 46551552 time 74ms
Block start at 46554624 time 64ms
Bad block found, start LBA : 46574592
Bad block found, start LBA : 46576384
Block start at 46576640 time 100ms
Block start at 46577920 time 112ms
Bad block found, start LBA : 46578432
Bad block found, start LBA : 46582272
Block start at 46582528 time 273ms
Block start at 46583040 time 64ms
Bad block found, start LBA : 46586624
Block start at 46590720 time 84ms
Block start at 46671104 time 59ms
Bad block found, start LBA : 46672128
Bad block found, start LBA : 46675968
Block start at 46676224 time 154ms
Block start at 618832128 time 107ms

From the report I understand that, only a portion of the hard drive has bad sectors only from the beginning (Bad block found, start LBA : 46675968 is the last one)

I'm planning to allocate till this as un-partitioned space and not use it. The question is how many GB's should I make as un-partitioned space so that I can continue to use my laptop.

I tried researching the internet for the meaning of LBA and its co-relation to hard drive size - all in vain. The Wiki page on LBA is of very little use in this context.

(Note: I do not mind losing data in case if the HDD fails suddenly. Just want to make the maximum out of this HDD)


From here, I understand that this formula which converts LBA to GB:

(LBA*512) / (1024^3)

By this formula: 46675968 / (1024^3) = 22.25GB - which I'd roundup as 25GB

Would this be correct?

  • All I'm looking for a is a LBA Vs GB table - so that I can cancel out so many inital GB's and use the rest of the HDD – Prasanna Aug 30 '15 at 18:25
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    The thing about bad blocks, they continue to happen, based on the fact you have performance issues you really should just replace the drive. Based on the bad block positions, you would have to lose 90% of your drive... – Ramhound Aug 30 '15 at 18:30
  • @Ramhound: Please see the edit. I found this formula from some site. Is that even correct? I'm getting 295GB as the answer when I apply the same formula to my last LBA #. I'm willing to trade even 50GB to keep the HDD (300-50=250GB - which is pretty good) – Prasanna Aug 30 '15 at 18:39
  • Think of the disk as an old record player; the arm that holds the heads does swing over the surfaces (often two sides even for a single platter). The swing is likely to be over the entire surface even if your partition is at one end - the surface may be broken or worn, and the arm moving over it will affect that portion - no matter what you do. The drive is going to fail eventually, and that might be quite a bit sooner than you think. – Hannu Aug 30 '15 at 20:54

You don't need to leave unpartitioned space.

While in OS:

Use Windows Full format. Uncheck the "Quick Format" checkbox during formatting a partition in windows.

While Installing Windows:

Format through command line diskpart. Before clicking install in Windows setup, enter shift + F10 and command prompt opens. Enter the command diskpart and it opens diskpart. Then enter commands..

list disk - lists available disks numbered from 0.

select disk 0 - selects disk 0 or 1st hard disk.

list partition - lists available partitions in disk 0.

select partition 0 - Selects the first partition in disk 0.

format fs=ntfs - Formats with file system ntfs. Here "quick" argument is omitted to force a full format.

Then close command prompt and install windows.

Such Full Format will mark all the bad blocks and will not use them.

But these bad blocks are going to increase over time rapidly and the disk is going to fail sometime later. Backup your data.

  • Thanks for the swift response. But if the space is not allocated to any partition, the HDD head need not (physically) move over that location right? So why would such a thing happen? – Prasanna Aug 30 '15 at 18:37
  • There could be muliple reasons for badblocks. Please go through this howtogeek.com/173463/… – Bharat G Aug 30 '15 at 18:47
  • Do you think the calculations are correct? See the *Edit section of the question – Prasanna Aug 30 '15 at 18:48
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    @Prasanna - The calculations depend on the drive and the block size of the drive. Just do what Bharat suggested – Ramhound Aug 30 '15 at 18:50
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    I think the calculation is correct , but only if the physical sector size of the disk is 512 Byte. Newer disks have 4k physical sector sizes. – Bharat G Aug 30 '15 at 18:57

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