🚀 go-pugleaf

ianst@refer.to.sig.au.invalid (Ian Staples) wrote:

>In article <39c053b9.5158254@news.alphalink.com.au>, 
>phaywood@alphalink.com.au.REMOVE.THIS.BIT wrote:
>>Groovy hepcat Steen Nielsen was jivin' on Tue, 12 Sep 2000 11:54:25
>>+0200 in alt.msdos.programmer.
>>help to fix bad sectores's a cool scene! Dig it!
>>
>>>Hi I need a dos program to repaer bad sectores on my harddrive
>>>can any one please tell me which program i should use.
>>
>>  You can't fix bad sectors. They're a fact of life. There's really
>>nothing you can do. Those sectors have gone to the great bit bucket 
>>in the sky.
>
>Is everything so clearly black or white, or can we have a bit
>of grey here too?

All of this depends on wether we're talking hardware level sectors, or
Filesystem blocks (Clusters). 

The former (hardware) is generally non-repairable or rather, drive's have
abilities to re-allocate those bad sectors, and use a "spare" sector in it's
place. In other words, though hard disks show no bad sectors (from new),
that doesn't mean that manufacturers have somehow managed to create flawless
media/platters. They just hide them, and give you some spares just in case.

The later (filesystem) can be have their respective structures "hacked" to
create or remove bad blocks. In the case of removing them, if the bad-block
is indeed faulty, your only causing trouble for yourself, later on.

So, to remove filesystem "bad-blocks", just format the partition (perhaps
deleting the partitions first, though it shouldn't be necessary).

To remove hardware "bad-sectors", the drive first has to be able to
re-allocate, and there have to be "spare-sectors" to be used in place of the
bad ones. Some drive's will do re-allocates as a normal course of their
operation, some will do re-allocates only during a "Low-Level Format", some
need a specialised "Low-Level Format", which toggles some state within the
drive first, and I'm sure there are other variations of the theme.

Note, none of what I've said above has anything to do with data recovery,
not that they asked for that.

>Up until 72 hours ago I may have unconditionally agreed with 
>the "great bit bucket" concept, but I'm now wondering about it...
>
>You see, a bloke who clearly knows more than I do about such things
>in general (he's a PC support professional) recently told me that 
>one of the ways some modern demo programs "know" whether they've been
>installed previously is to mark a sector bad.  [And, presumably, put
>a bit of stuff in that sector to confirm that they've done it when
>they look again later?]

This is (usually) an old practice, which "hacks" the filesystem to achieve
this...

>
>If this is so, then maybe there would be a way to recover such lost
>space?  Whether it would be worth the effort is another issue -- 
>I guess it depends whether this scenario is real; and, if so, how many 
>demos you trial. ;-)

Format the partition unconditionally, or for a FAT partition, use something
like Nortons DiskTool - Mark a Cluster.

For hardware ones, contact the manufacturer. It's quite likely that the
drive has exhuasted any "spare-sectors" already :( ... Many of the ones I've
tried re-allocates on, continue to deteriorate for quite some time. With
luck, they may stabilise.

  __   __  ________________________________________________________
 //)) //))| Richard RUDEK. MicroDek. Chatswood, Sydney. Australia. |
//\\ //\\ |http://microdek.homepage.com/                           |
          |________________________________________________________|