OS/2 Shareware BBS: 11 Util/11-Util.zip/hpfsut02.zip/readme.txt

Text File | 1999-11-27 | 13KB | 296 lines

HPFSUtil v0.02 by Mike Ruskai <[e-mail]>

This program is a consolidation of various test programs I put together
while investigating the structure of HPFS, with the original purpose of
discovering just how much space HPFS takes up for itself, and how that
amount correlates with drive size.

The program usage:

Usage: hpfsutil.exe <drive letter> <options>

<drive letter> - letter of HPFS drive to process

Options:

/GD - report current dirty bit status
/DT - toggle dirty bit
/SD:<T/F> - set dirty status to True or False
/FS - compare actual and reported free space
/SU - show HPFS system space usage
/BS - show bad sector count
/SHSU - display contents of SuperBlock
/SHSP - display contents of SpareBlock
/SHSPFD - display SpareBlock with full spare DirBlk list
/DS:<sect>[-<sect>] - dump sector(s) to file
/FN:<filename> - filename to dump sectors to; default sectdata.dat
/NL - don't use IBM linedraw characters

Argument order is unimportant.

You may specify as many different options as you want on the same
commandline.  They will be executed in a set order (not the order you
specify them).  Duplicate options aren't permitted (including duplicate
sector dumps - you'll have to run the program multiple times for multiple
sector ranges).  Also, the DT and SD options are mutually exclusive.

Explanation of the options:

GD - Get the current dirty status of the drive.  This just checks bit 0 of
the partition status byte (the 9th byte in the HPFS SpareBlock), and
reports accordingly (1 = dirty; 0 = clean).

***

DT - Toggle the dirty status of the drive.  If it's dirty, it's set clean.
If it's clean, it's set dirty.  The program reports which action was taken.

SD:<T/F> - This sets the dirty status to True or False (/SD:T or /SD:F),
regardless of what the current status is.  If no errors are encountered, it
reports the change.

***

** Note **

The above two options write directly to your drive.  I am in no way
responsible for any data loss you may have due to any problems coinciding
with using this program with either of these options.  Use them at your own
peril.

That said, they work fine here, and should work fine anywhere.  But if bad
information is given by OS/2 to the program, there's no guarantee that the
correct sector is read and written back to disk.

**

FS - This traverses all of the freespace bitmaps on the drive, tallying up
free sectors, and compares the results with what DosQueryFSInfo() reports.
The implementation of HPFS on Warp 4 (and possibly others) has a bug which
reports 4096 fewer sectors free than are actually free, on drives from
120MB to 3GB (the range I tested).  A 10MB drive had a discrepancy of 443
sectors.  This space is free, but unreachable in OS/2.

SU - Display an itemized list of the amount of space reserved by HPFS.
This doesn't include any HPFS structures created for the purpose of
allocating data files (FNodes, ALSECs, etc.).

BS - Display the bad sector count, as reported by HPFS (time to replace the
drive if any are found).

SHSU - Output a formatted display of the HPFS SuperBlock sector.  The
offset field is in the format hex/decimal.  The hex is logical (0-based),
and the decimal is absolute (1-based).  The size of the data can be
determined by noting the length of the hex value.  Each two hex digits
indicate one byte of data.  See further on in this file for detailed info
on each item.

SHSP<FD> - Output a formatted display of the HPFS SpareBlock sector.  The
format is the same as for the SuperBlock display.  The addition of FD
prompts a complete list of the spare DirBlk locations.  By default, only
the first is listed (the SpareBlock contains the entire list).  See further
on in this file for detailed info on each item.

DS:<sect>-[<sect>] - Dump the sector or sector range to file (default
sectdata.dat - see next option for how to change this).  The <sect> value
must be a decimal number from 0 to the number of sectors on the drive
(exceeding the boundary will report an error).  There are three macros that
can be used in place of a decimal value: "boot", "super", and "spare"
(without the quotes).  These correspond to the locations of the BootBlock
(LSN 0), SuperBlock (LSN 16), and SpareBlock (LSN 17), respectively.

FN:<filename> - This specifies an alternate sector data filename (default
is sectdata.dat).  If the file can't be opened, an error will be reported.

NL - This tells the program to not use IBM linedraw characters, in the
event that your codepage makes those character values into something other
than lines.  They are replaced with standard ASCII characters.

The HPFS SuperBlock:

64-bit SuperBlock signature - self explanatory.

HPFS version - reports 2 for HPFS and HPFS386.

Vol size (2:<=4GB; 3:>4GB) - indicates whether or not drive is larger than
    4GB - a value of 2 means less than or equal to 4GB, while 3 means
    larger than 4GB.

Root dir FNode location - self explanatory.

Total sector count  - total number of sectors on the drive, including those
    taken up by system structures.

Bad sector count - actually *known* bad sector count, which should be 0,
    unless your drive is failing.

Free space bitmap list - location of the list, which consists of
    consecutive 4-byte sector numbers, indicating the location of one
    four-sector bitmap each.  The size of the list depends on the size of
    the drive - it's a minimum of four sectors, and increases four sectors
    at a time as needed to accomodate larger drives.

Spare bitmap list - probably originally for accomodating larger drives that
    need more freespace bitmaps than four sectors could list, but is unused
    now, and always 0, since the main bitmap list is larger when necessary.

Bad sector list - location of a four-sector list of bad sectors.

Spare bad sector list - If you need more than four sectors to list the
    number of bad sectors, this would be used (and your drive would really
    be shot).

Date CHKDSK /F last run - in the form of a 4-byte Unix timestamp.

Date last optimized - presumably for application use, but GammaTech's
    optimizer doesn't use it.

Dir band sector count - number of sectors in the directory band.

Directory band start - location of first sector of directory band.

Directory band end - location of last sector of directory band.

Directory band bitmap - four sectors covering the allocation of the
    directory band.

First ACL block location - location of eight-sector block of ACL's, which
    are only used by HPFS386.

The HPFS SpareBlock:

64-bit SpareBlock signature - self explanatory.

Partition status byte - a bitmask, with the following definitions:

    0: Dirty flag
    1: Spare DirBlk's used
    2: Hotfix sectors used
    3: Bad sectors exist
    4: Bad bitmaps exist
    5: Fast formatted
    6: Unknown
    7: Written by old IFS

    In each case, 1 means true, 0 means false.

Hotfix list location - location of four-sector list of hotfix sector
    numbers.  The first 400 bytes of the first sector are empty, and used
    to store the locations of any sectors which have been hotfixed (the
    position of the sector number says which hotfix sector contains the
    data).

Hotfix sectors in use - the count of hotfix sectors in use.

Total hotfix sectors - the total number of hotfix sectors, which is always
    100 (which is why only 400 bytes in the list are reserved).

Spare DirBlk count - the number of spare directory blocks there are, which
    exist in the event that space runs out while making directory
    adjustments.  The default count is 20.

Free spare DirBlk's - the number of spare DirBlks not in use.

Code page list location - the sector address of the code page list, which
    contains the code page numbers, and some other info.  The next sector
    contains the code pages themselves.

Number of code pages - number of installed code pages, which is always 2.

HPFS SuperBlock 32-bit CRC - cyclic redundancy check of the SuperBlock,
    which is used by HPFS386 to determine when the SuperBlock has been
    altered.

HPFS SpareBlock 32-bit CRC - cyclic redundancy check of the SpareBlock,
    used by HPFS386 to determine when the SpareBlock has been altered.

Spare DirBlk #1-#20 location - sector addresses of the 20 spare directory
    blocks.  Each address is four sectors apart, since a directory block is
    four sectors long.

Disclaimer:

The author is in no way responsible for anything bad happening to you or
your computer after you run this program.  The /SD and /DT options are the
only ones which directly write information to your drive (/DS uses the
standard file system methods of writing), but for all I know, loading this
program into memory may be the last straw that breaks your power supply's
fuse, while you were in the middle of using Partition Magic on your
sensitive data partition with no backup.

Source:

The source code to this program is included in the archive, in a separate
archive entitled source.zip.  This source may be freely modified and
compiled, but credit where credit is due would be nice.  Each C file should
be compiled separately, and all the objects linked together.

There are few source comments, but the code should be self-explanatory
(since I don't use obscure variable names or bad structure, unlike a
disconcerting number of programmers out there).

Acknowledgements:

Virtually all information about the structure of HPFS was obtained from the
EDM/2 articles about HPFS by Dan Bridges.  Additional info was provided by
Jan Van Wijk, author of the DFSEE utility program.

In addition, some of the OS/2-specific programming tasks were accomplished
with the indirect help of various people on UseNet (by reading their posts
from a Deja.com search), most notably Peter Fitzsimmons, who seems to have
answered virtually every OS/2 programming question conceivable at one time
or another.

Known problems/limitations:

There exists the possibility that a bad sector turn up where a freespace
bitmap should be.  I don't yet know how to deal with this situation
properly, so if the bad bitmap bit is set in the partition status, the free
space discrepancy option won't run.  No check is currently done to see if
there are any bad sectors in the range specified to dump to file.  Either
the read will succeed (meaning the bad sector either isn't bad, or only bad
some of the time), or it'll fail, stopping the sector dump.

Caveats:

If you use the current drive for the sector data dump file, and you choose
a sector range that includes free sectors, there's a decent chance that
what you're reading will overlap what's being written to the dump file.
This won't cause any errors, but it'll make the utility of the dump file
rather specious.

Questions/comments/bug reports:

Send them all to [e-mail], and I'll ignore them or act on
them at my discretion.

History:

11-22-1999  -   Original release.

11-27-1999  -   Changed sector read function to only read one sector at a
                time, since garbage would be returned if a track boundary
                is reached during a multiple-sector read.  This slows
                things down a bit during the free space discrepancy scan.

                Changed checking of freespace bitmap data to increase
                performance, so much of the performance loss above is
                regained here.

                Changed loops in display routines to memset() calls, which
                speeds them up a bit.

                Fixed an error in the calculation of how many bitmap list
                sectors are required, which hopefully is what caused the
                problems people have been pointing out.

                Compile this time with VACPP 3.08's Compact optimization.
                Had Speed optimization bug pointed out by someone else,
                which no longer affects the program (the loops in the
                display functions were being incorrectly optimized, but
                have been removed).  Other VACPP 3.08 users might want to
                look out for this type of error, which can be worked around
                by making the loop counter variable 'volatile'.

                This is version 0.02