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MANUAL.DOC
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1986-10-19
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===========================================================================
Veronly is a Public Domain subset of Verify.ttp which is
copyrighted and will be part of a future hard disk utility
package. If you desire to have a copy now, contact me on
any of several ST BBS's that PC Pursuit reaches or write:
Thomas Zerucha
24075 Lee Baker
Southfield, MI 48075
===========================================================================
VERIFY.TTP - Disk file structure diagnostic and repair
VERonly.TTP - Does everything but repair - diagnoses disk structure problems.
GEMDOS format verify/repair utility
Format verification for all known volumes
Can be used in /auto, change to verify.prg
If no parameter is specified, the verify mode is entered:
Lists disks logged in system, and any errors found on them.
Tests performed:
FATs identical
FATs have no invalid links
Directory entry begins at beginning of FAT chain
Subdirectories link properly (. and .. files)
Directory entry size consistent with number of clusters used
Single Volume Label
No used clusters without files
Any of these errors will cause an error message, in addition, any
files threatened may be listed. If no disk is in a drive, a
message will be printed, but not as an error.
If no errors exist on any disks, the program will end normally,
(back to desktop or shell) otherwise a list of disks with
errors will be printed and the program will pause until any
key is pressed.
Use redirection to produce a log, but remember to hit a key to end
the pause on error (e.g.)
(verify.ttp) >a:verlog.txt
Remember that NO OPTIONS are allowed in this mode, if they are
specified, they will normally be ignored.
Parameters (any order):
[<drive>]
<drive> is which drive to analyze and repair
[-<option list>]
you may use any number of options, with one or more hyphens,
e.g. -p -r is equivalent to -rp, but all require an explicit drive
to be specified
options:
-r repair the disk (if not specified, only a verify
is performed and log information printed)
-f print out fat
-d print a directory
-p print all information
-e list threatened files only
-s single drive mode (pauses to allow disk change)
-x allocates more memory (dir is much bigger than FAT says)
(you will be prompted if this is needed)
Statistics:
FAT:
Tot(al) - number of clusters on disk
Starts - number of clusters that begin chains
Ends - number of EOF markers
erend - number of chains ending at an invalid cluster
inval - number of invalid clusters (not free, next, or EOF)
colls - number of collisions (chains merge)
cont - number of contiguous clusters
ncont - number of non-contiguous clusters
The FAT is stored as a linked list. Each chain should have one
beginning and end at an EOF marker. All other clusters are marked
reserved/bad or free and should not be part of any chain. If a
cluster points to the one following it, it is considered contiguous,
otherwise, if it is not an EOF it is non-contiguous. Contiguous
chains are faster to access.
Cross Reference Statistics:
Files - total number of files in directory and FAT
Fclus - clusters allocated to known files
Free - available clusters
oclus - "orphan" clusters - allocated, but no file uses them
recov - Neither file nor orphan, recoverable
unuse - reserved clusters (normally bad blocks)
unkn - unknown (deeper xref necessary, done in repair)
orphs - number of "orphan" files
ordec - decendents of orphan directory
error - number of threatened or bad files
Noerr - number of perfect files.
Each beginning and ending in the FAT is matched with the directory,
and any differences noted. If a chain is allocated, but no
directory entry matches, it is flagged as an "orphan". This can
occur when deletes are interrupted. If a free block ends a file
chain, it's status is unknown, but can be resolved futher. Since
it is neither Free or allocated, it is counted "unkn". Further
repair will either change it to EOF or Free. This applies to
some other situations. Recoverable is not marked free, but cannot
(or should not) be recovered into a file, but will be marked free
when repaired.
This information may not be of interest except to users who
know about GEMDOS and may want to do some editing with other
tools to manually restore some files. Otherwise it useful only
to point out which files may be invalid or altered, and those
which are created by the utility. It will also indicate the
general health of the disk if repair is not specified.
A list of the threatened files will be produced if the E option
is specified.
Orphan files may be deleted if necessary. Since it is not possible
to know if the file was really deleted or the directory entry
was trashed, the files are just recovered (with a guess as to the
type). If nothing was missing these are probabaly files which
the delete merely failed to complete, so the space should be
recovered by deleting the files. Otherwise (e.g. if a source
file was missing and FIX_xxxx.TXT appears) look at or run (carefully,
since programs may delete some files) the file to see what happens.
Orphan descendants occur when the entry for a directory is missing
or erased. The file is recovered as a directory, and the directory
is read and any files within are recovered.
Collisions occur when two files link through the same cluster. The
part of the file left usually belongs only to one of these files,
but deleting the other file will remove this area as well. The
FAT chain is cleaved based on the most likely owner. A related
problem is a bad end, the last cluster in the file is not the EOF
mark, but a free cluster (which can be allocated by another file
causing a collision), or points outside of the storage area of the
disk (e.g track 120 on an 80 track disk). These are changed to EOF's
or the cluster pointing to this end is changed to EOF.
If repair is specified, the following log will be added:
Repair info:
comments will be indented
<path>, bad start, removed
<path>, excessive size, removed
first, any invalid files are removed from the root to make
room for any directories that need to be created (in case
the root is wiped and has no available entries). THIS WILL
ALSO REMOVE THE VOLUME LABEL. The tests for validity are
simple at this point, only something obvious is zapped
<path>, inserting as directory
directories that have been found are restored
Resolving duplicate starts
<path>
<path>
. . .
more than one directory entry start at the same