[comp.sys.ibm.pc] Bad sectors

jwbirdsa@phoenix.Princeton.EDU (James Webster Birdsall) (01/11/89)

   I seem to recall that CHKDSK in its report gives the number of bytes
occupied by bad sectors. Is this correct? I have two hard drives.
CHKDSK makes no mention of bad sectors on either one of them. Have I
been incredibly lucky? Is the bad sector rate on hard disks lower than I
think it is? Is there some switch I need to give CHKDSK to make it
report bad sectors? What?
   For your information, I have a Plus Hardcard (10 meg) and a Seagate
238R.
   Thanks in advance...

========================================================================
! James W. Birdsall               Compu$erve:  71261,1731              !
! jwbirdsa@phoenix.Princeton.EDU  jwbirdsa@bogey.Princeton.EDU         !
! jwbirdsa@pucc.BITNET            ...allegra!princeton!phoenix!jwbirdsa!
========================================================================
!  During emergency landing, replace dinner tray and bring seat to     !
!  upright position. Extinuish all smoking materials... including      !
!  spacecraft, if possible.  --Calvin                                  !
========================================================================

dougm@kuhub.cc.ukans.edu (Douglas Miller) (01/11/89)

  CHKDSK will not detect and set bad clusters (containing bad sectors).  It
is only capable of checking the starting cluster numbers in the directories
against the file allocation cluster chains for the various files.  On the
basis of that information it will tell you which chains are unconnected
or cross connected or have multiple references in the directories.  CHKDSK
will, incidentally, report any bad cluster marks it may have found while
analyzing the FAT.
  In order to set the bad sectors you must feed the information from the
bad sector map (usually attached to the disk in the form of a sticker)
provided by the manufacturer to a program designed to perform that function.
You may also do the calculations and the setting by hand (NU or
Debug).  The bad cluster mark is FF7 hex for 12-bit MSDOS FATs and FFF7
for the 16-bit variety.  As for DOS 4.0 and UNIX I cannot say.
  At any rate, I think there is a program called Disk Manager that will do
what you require.  Perhaps someone out there will be so kind as to provide
the correct information if I have been speaking from within my lower 
intestine.

--Another know-nothing opinion from the desk of D. Miller.