Category : Assembly Language Source Code
Archive   : DOCFILES.ZIP
Filename : DISKSCAN.DOC

 
Output of file : DISKSCAN.DOC contained in archive : DOCFILES.ZIP

DISKSCAN Charles Petzold
Command PC Magazine, Vol 5, No 8
Copyright 1986 Ziff-Davis Publishing Company
______________________________________________________

Purpose: Locates and identifies disk errors on hard
and floppy disks, Bernoulli Boxes or other
similar storage devices.

Format: DISKSCAN [d:]

Remarks: The DOS "Abort, Retry, Ignore?" and the
CHKDSK "x lost clusters found" messages tend
to appear after it is too late to save
possibly valuable data. Regular use of
DISKSCAN will show when a hard disk is
beginning to go bad--for example, when a
specific sector or two in an as-yet
unallocated cluster has become unusable since
the disk was formatted. (DOS marks and does
not use bad clusters it finds while
formatting. DISKSCAN reports these "Flagged
as bad.")

DISKSCAN error messages include:

CRC Error: Data checksum as recalculated
during read does not agree with checksum
stored on disk when written.
Sector Not Found: Sector boundary created
during formatting is no longer readable.
File Alloc. Table and Can't Read FAT: Very
serious error: Back up what you can
with COPY and reformat disk before
trying to put files back on it.
Boot Sector: If this sector of a hard disk
goes bad, put a DOS disk in drive A: and
issue SYS C: command. Then COPY
COMMAND.COM C:. This will put a fresh
copy of the system files on drive C:.
If this does not work, boot up again
from the external DOS floppy disk, back
up all hard disk files, and reformat the
hard disk.
Root Directory: Errors here could keep you
from later being able to load a file or
save updates to it. CHKDSK will
probably indicate unallocated cluster
chains or cross-linked files, and you
may have to use CHKDSK/F to save what
you can.
Unallocated: As yet, not serious, as the bad
sector is not being used. When it is,
though, and you try to save a file with
this sector, you'll get an "Abort,
Retry, Ignore" message. Select "Ignore"
to save what you can, then REName the
file and save again under the new name.
Use RECOVER filename with the original
file; this will cause DOS to flag its
cluster(s) as bad. (DISKSCAN does not
enter the bad cluster numbers in the
File Allocation Table; FORMAT and
RECOVER do.) Then delete the original
(RECOVERed) filename and check the
second version you saved (under the new
name) to see how much (if any) of it is
usable.
Used by file: While DISKSCAN reports the bad
sector number, it does not do a cross-
check to see which of your files is
using that sector. You may be able to
identify this by issuing the command

SWEEP COPY *.* NUL

When COPY encounters the file with the
bad sector it will report "Abort, Retry,
Ignore." Note the bad file and press
"I" to continue.
Read Fault and General Failure: The sectors
so designated are bad, but the errors
reported don't fall into any of the
above categories.

Notes:

1. Requires DOS 2.0 or higher.



  3 Responses to “Category : Assembly Language Source Code
Archive   : DOCFILES.ZIP
Filename : DISKSCAN.DOC

  1. Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

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