DISKED
The DISK EDitor
For IBM-PC/XT/AT
Computers
Software and Manual
Designed and Written
by Gregg Jennings
Software Version 2.4
Documentation Version 2.1
December 2, 1993
(c) 1989-1993 by Gregg Jennings
ALL WRONGS RESERVED
DISKED page 2
WHAT DISKED IS
DISKED is a simple to use disk editor and data recovery program for
IBM-PC/XT/AT and compatible computers. It allows the editing of any
sector and the saving of sectors to a file. DISKED provides a way to
recover data from disks with a damaged BOOT sector, damaged FATs, and
damaged directory areas, allowing the saving of otherwise lost data.
DISKED is meant to be very easy to learn and to use -- it is operated
by entering easy to remember single letter commands. Its simple
interface enables the user to have full control over the program,
letting it be run with full confidence and assurance. DISKED was and
still is being developed with ease of use as the number one feature.
WHAT DISKED IS NOT
Although DISKED can recover an erased file's data, DISKED cannot
unerase a file. DISKED also does not format nor change any parameters
of the format of a disk -- does not fix bad sectors -- does no file
copying, moving or deleting -- there are better utilities for that.
All DISKED does is read, write, and store any available sector of a
disk in a simple and easy, yet powerful and versatile way.
┌──────────────────────────────────┐
│ BUT REMEMBER │
│DISKED CAN RECOVER DATA FROM DISKS│
│ WHEN DOS UTILITIES CANNOT │
└──────────────────────────────────┘
REQUIREMENTS
This version of DISKED requires an IBM compatible with 128KB of memory
and DOS version 3.0 or higher. DISKED supports all IBM PC/XT/AT drive
formats.
DISKED page 3
TUTORIAL
DISKED comes up at the disk's root directory sector and is in a
combined command and edit mode.
DISKED displays each sector as you move about the disk. Movement is
done by the direction keys similar to paging through a text document --
you always know exactly where you are on the disk.
There are two available areas for data; a sector buffer that holds
selected sector's data and a file buffer that allows saving sector data
for writing to a disk file.
The sector buffer can be changed in a manner similar to a debugger and
can be written back to the disk. There is also a spare sector buffer
to which a sector can be stored and retrieved for copying to another
sector.
Data is saved by appending single or multiple sectors into the file
buffer. The file buffer can then be observed and changed, written to a
disk file, emptied, or more sectors appended or unappended. Any number
of absolute sectors can also be written to a file.
These features produce a very versatile program.
DISKED page 4
Section 1
Using DISKED
1.1 Documentation Notes
This document assumes that the user knows certain computer terms.
Specific terms are: hexadecimal numbers; strings and bytes; tracks,
sectors and clusters; control characters and ASCII.
In this documentation, the word disk is used to mean either the hard
disk drive or a floppy diskette -- the media that holds the data; the
word drive use used as meaning the DOS drive as in 'A:' or 'C:', as
well as any logical drives or ram drives when device drivers are used.
The word sector is used in two different and distinct ways -- there are
physical and logical sectors of a disk. The physical sector references
pertain to the disk drive hardware, the logical sectors pertain to DOS.
Physical sectors come in to play, as far as DISKED is concerned, with
the 's' (select physical position) command and parameter display only.
All other references to sectors are logical, which run from 0 to the
end of the disk.
1.1.1 Command Input Conventions
The commands, arguments, and keys designated in this manual use the
following conventions:
Convention Description
D A valid drive letter.
n A decimal or hexadecimal number.
x A hexadecimal number.
s An ASCII string.
c An ASCII character.
C A letter.
^C A control character.
'c' A DISKED command key.
's' A DISKED keyword.
| More than one key will perform the same command.
DISKED page 5
end A cursor key.
F1 Function key.
TAB Other special key.
1.1.2 Keyboard Input
Because some commands are instantaneous any command typed that needs an
argument cannot be erased (i.e. a backspace or delete will not erase
it), yet a return or an escape will usually cancel. Commands that do
not require an argument will be performed without a return.
When a command argument is needed, during input, the backspace will
delete characters, a ^C or ESC will cancel the command, a ^U will
delete all input. A return, a space, or a comma ends the input. A
return will be automatically entered if the maximum number of
characters is input.
When a number argument needs to be input, only numbers will be
accepted. Any number required will be of 1 to 5 places so, depending
on the type of argument required, too large of a number cannot be
entered. Any argument that is out of bounds will just be ignored.
When more than one number needs to be input, a return, a space, or a
comma can be used to separate the numbers.
Whenever DISKED asks for confirmation of a command, a capital or
lowercase Y will confirm and any other key will cancel.
DISKED page 6
Section 2
Commands
Note: any command that deals with files that exist on the disk will be
disabled if file indexing is off (cf. 3.1.0).
2.1 Drives
Command Function
lD Log in drive D as the disk to use. The file buffer is
left alone, allowing for data recovery to the same drive.
The first sector of the root directory area is selected
after the log in (cf. 3.1.0).
^L Re-log current drive. This should be done whenever the
file buffer is written to the current disk and filename
display is on (cf. 3.1.0).
When a floppy disk has been changed it does not have to be
logged in unless the new disk is of a different format or
filename displaying is wanted.
2.2 Moving
When moving, the disk is treated as circular. Movement past either end
results in "wrapping" around to the other end. Each sector contents is
displayed after every movement. The sector data can be displayed in a
variety of formats; 16 bytes per line hex/ASCII (only the first 128
bytes are displayed, this is the default), 24 bytes per line hex/ASCII
(the full sector contents), ASCII only, and a directory format. The
format is selectable (cf. 3.1.0).
Command Function
sn,n,n Select the track, sector, and head respectfully, separated
by commas or spaces. A return will end the input. Any
parameter may be omitted leaving it unchanged.
sb Select the BOOT sector.
sf Select the beginning of the first FAT area.
Sn Select the first sector of cluster n.
^Sn Select the logical sector n.
end Select last sector.
DISKED page 7
home Select the beginning of the root directory.
n Next sector.
^N|pgdn Next track.
N|right Next cluster.
b Back sector.
^B|pgup Back track.
B|left Back cluster.
+n Increment n sectors.
-n Decrement n sectors.
r Range forward by sectors. If the key hit is a number the
pause between sectors is increased or decreased, 1 being
the fastest, 9 the slowest. A space will pause, any other
key will cancel.
^R Range backward.
R Range by clusters.
1-9 Select the tagged sector. See the 't' command.
j|^right Jump to the next cluster of the file that the current
cluster is allocated to.
J|^left Jump to the previous cluster of the file that the current
cluster is allocated to.
^home Start cluster of file that the current cluster is
allocated to.
^end End cluster of the file that the current cluster is
allocated to.
Shft-right Next free cluster.
Shft-left Back free cluster.
2.3 Editing
Command Function
DISKED page 8
cn Change sector contents starting at buffer location n. The
address of the sector offset is shown along with the data
in hex and ASCII. A return or a space leaves the data
alone and advances to the next, a backspace advances to
the previous, always wrapping around at the extremes of
the buffer.
The the buffer position can be changed and new data can be
entered by typing a new value in a variety of ways.
Table 2.1: Change Formats
x hex number
'c ASCII character
^C control character
"s string
CR/SP next location
TAB go to location 00
=x go to location x
\x go to number x
\'c go to character c
\^C go to control character C
-x1,x2 fill x1 places of x2
+x1,x2 replace all x1 with x2
?|/ display command summary
.|ESC exit change
Changes are not written to the disk. See the 'w' command.
C Change file buffer contents.
^C Change the sector buffer in a directory format. The file
names, file attributes, and file times and dates can be
changed. The file attributes are toggled by the spacebar;
the volume label or deleted files can not be changed. The
DOS system files must not be changed. There is no out-
of-bounds checking for the times and dates. If the sector
is not a directory sector the change fields will still be
in the directory format.
Table 2.2: Directory Change
CR/SP next entry
TAB next field
SHFT-TAB previous field
=n go to entry n
?|/ display command summary
.|ESC exit change
Changes are not written to the disk. See the 'w' command.
DISKED page 9
k Kill any changes to the sector buffer. After any changes
have been made to the sector buffer, a 'k' will restore it
to its original state. The sector is not written to the
disk. The file buffer cannot be unchanged.
w Write the sector buffer back to the disk, presumably after
changes have been made, or after a saved sector has been
retrieved by the '<' command. A 'w' in the BOOT or FAT
area will cause a warning message to be displayed only and
will always ask for confirmation.
Care should be used when in the BOOT sector, any FAT
sector, or any directory area.
This command has to be enabled by an entry in the
DISKED.INI file (cf. 3.2.1) and turned on from within
DISKED (cf. 3.1.0).
2.4 Copying
The copy commands copy disk data into the file buffer. All commands
indicate when the file buffer is full. The size of the file buffer is
displayed by the BS command, the amount of the file buffer contents is
displayed at the prompt.
Command Function
a Append the current sector into the file buffer.
A Append the current cluster.
^An1,n2 Append n2 bytes from offset n1 of the sector.
u Unappend a sector size amount of bytes out of the file
buffer.
U Unappend a cluster size amount of bytes.
^Un Unappend n bytes.
gn Get n sectors. Append the next n sectors, starting from
the current sector, into the file buffer, leaving the
current sector selected. Any key hit while cancel the
getting.
g0 Get the entire current track.
g1 Get the rest of the track, starting from the current
sector.
DISKED page 10
^Gn Get n sectors and move n+1 sectors.
e Empty the file buffer.
^E Empty the file buffer regardless of the 'verify' keyword
(cf. 3.1.0).
2.5 Storing
Any one sector can be stored in a special buffer for retrieval at any
time. This special buffer contents remains the same until another
sector is stored.
Command Function
> Store sector.
< Retrieve sector. If there is no sector stored nothing
happens, if there is, the sector buffer is overwritten by
the stored sector and displayed as by a normal sector
move. The sector is not written to the disk.
2.6 Files
During any file input or output, the buffer will be translated
according to the 'mask', 'strip' and 'convert' keywords except when
noted (cf. 0). During file reading or writing any key hit will cancel.
Command Function
ps Put the file buffer to file s.
^Ps Put the file buffer to file s without any character
translations. All bytes will be written, including any
EOF characters.
Pn1,n2,s Put n2 sectors, starting at n1 (or the current sector if
n2 is a left out) to file s without any translations.
is Insert the file s into the file buffer (as much as
possible).
^Is Insert the file s without any character translations.
Is Insert the file that the current sector is allocated to.
m Map out the clusters of the file that the current cluster
is allocated to.
DISKED page 11
2.7 Displaying
Command Function
/ List command summary.
? Extra command summary.
BS Display drive parameters.
SPACE Display top 128 bytes of sector buffer.
CR Display the next 384 bytes.
^J Display position.
dn Display the file buffer a page (256 bytes) at a time
starting from address n, in a hex/ASCII format.
vn View the file buffer contents with translation according
to the translation keywords.
^V View the sector buffer. The viewing will not pause until
the end of the sector is reached.
Shft-F1 Display top 128 bytes of sector buffer.
Shft-F2 Display full sector buffer.
Shft-F3 View the sector buffer.
Shft-F4 Directory display the file buffer.
2.8 Searching
Command Function
fs Find string s; a null response will search for the
previously entered string. Any key hit while in progress
will stop the search. The following control characters
can be embedded in the string:
DISKED page 12
Table 2.3: Find Control Charcters
\0 null
\a bell
\f form feed
\n line feed
\r return
\s space
\t tab
\xxx hexadecimal value xx
\\ backslash
Extended characters (values greater than '~' or 7Eh)
can be entered by Alt-Keypad sequences.
^Fs Find s on the disk searching backward.
Fs Find s in the file buffer.
2.9 Exiting
Command Function
q|.|ESC Return to DOS. The drive and directory that was current
when DISKED was loaded will be re-selected.
^Q Return to DOS regardless of the 'verify' keyword.
2.10 Miscellaneous
Command Function
zs Show and/or change keywords (cf 2).
Z Show keywords only.
, Toggle input radix between decimal and hexadecimal. All
numbers displayed or input will be either decimal or
hexadecimal. The default is decimal.
F1 Display the name of and the files in the currently
selected directory. This will be the directory for all
default file I/O.
F2 Display all files on the disk. A space will pause the
displaying, an ESC will abort.
F3 Display the number of files and directories on the disk.
DISKED page 13
F4s Make the directory s the current directory for all default
file I/O.
F5 Re-read current sector.
F6 Append sector with 'strip'; ignores the 'strip' keyword.
F7 Append sector with 'convert'; ignores the 'convert'
keyword.
F8 Append sector with 'mask'; ignores the 'mask' keyword.
F9 Append sector with translation as per the 'mask', 'strip'
and 'convert' keywords.'
F10s Set to the first cluster of the file or directory s. The
full path name need not be given unless there are
duplicate files on the disk.
tn Tag the current sector. Assigns n (1-9) to the current
sector, enabling the selection of that sector by typing
the corresponding number.
x View the DISKED.INI file.
X View the DISKED.SAV file.
^X Save the current state of DISKED to a file named
DISKED.SAV. The file will be written to the directory
named in the INIT environment variable or to the default
directory. The drive, sector, tagged sector list, and
last search string will be saved.
^Z Restore DISKED state by reading the DISKED.SAV file.
DISKED page 14
Section 3
DISKED Initialization
3.1 DISKED Keywords
Keywords are the names of certain parameters indicating how some
commands will function.
Keyword Function
ascii Displays sector data to the screen as the '^V' command,
with translation according to the translation keywords.
convert Converts all non-printable bytes to its hexadecimal
equivalent between angle brackets during file I/O or when
the file buffer is viewed to the screen.
display Displays a description of and information about the
command before it is performed.
files All filenames on the disk will be read and indexed so that
the filename can be matched to each cluster and displayed.
get A move is made after sectors are appended using the 'g'
command.
home The first sector of the root directory area of a disk is
selected after it is logged in.
mask Masks off the high bit of all bytes during file I/O or
when the file buffer is viewed to the screen.
logical Displays disk information without references to the
physical properties of the disk.
partial Displays just the first 128 bytes of a sector when not in
Ascii mode. Otherwise 512 bytes are displayed.
strip Strips out (ignores) all non-printable bytes during file
I/O or when the file buffer viewed to the screen.
translate Displays directory sectors in a directory format.
verify Asks for confirmation when performing any of the more
powerful commands.
write Enables the writing of sectors to the disk.
DISKED page 15
These parameters can be turned on and off (or enabled and disabled)
from within DISKED or by an initialization file. By default they are
all on except for 'ascii', 'files' and 'write'.
3.2 Changing DISKED Parameters
3.2.1 Outside DISKED
DISKED will look for a DISKED.INI file to set or change the DISKED
keywords. In the DISKED.INI file enter the keyword followed by either
'on' or 'off'. DISKED will first search the directory indicated by the
"INIT" DOS environment variable, then the directory in which DISKED was
executed from, and finally the default directory.
3.2.2 Inside DISKED
By the use of the 'z' command these parameters can be changed inside
DISKED. The 'z' is followed by a string containing the first letter of
the keyword to be changed, toggling it on or off. Only the keyword
letters are valid, all other characters are ignored. When the
'display' parameter is on, all keywords and their values are shown
before inputting.
For added protection, the 'write' parameter must be in DISKED.INI and
then turned on by the 'z' command for the 'w' command to work.
A quicker way of changing the keywords is by using the Alt key and the
first letter. The parameter is changed and its new value is displayed.
DISKED page 16
Section 4
Hints on Usage
4.1 Bad Sectors
4.1.1 Damage
Damage is when a sector can not be read due to physical defects on the
disk. Damage will most likely be trapped by DOS with the standard
message; if retrying does eventually result in the sector being read
you are in luck. DISKED does not do anything fancy when reading
1
sectors -- it relies on DOS .
Damage in the data area results in DISKED not being able to read those
sectors and if they lie in a file then only the readable parts of the
file can be recovered. Executable files cannot be recovered in this
situation.
Damage in the BOOT area can be circumvented by logging in a good disk
of the same format then putting in the disk with the bad BOOT sector.
DISKED can not log on to a hard drive if it has a damaged BOOT sector
only if it is "known" by the operating system (if DOS does not issue
the "Invalid drive specification" message).
If damage is found in the FAT or in a directory area, DISKED will
automatically turn off the 'files' keyword.
DISKED makes no use the FAT bad cluster information.
4.1.2 Corruption
Corrupt data is invalid information on the disk; this results just as
if the areas were damaged if the corruption lies in the BOOT, FAT, or
directory areas, for normal DOS utilities and applications.
Corrupt data can be a foreign type of media (not really corrupt but
unable to be interpreted), a disk that was inadvertently written to by
power failures or system crashes, or, on single floppy systems (like
laptops), a disk was changed at the wrong time causing another disk's
data written on it.
_______________________________________________________________________
1. Central Point Software Inc. has an excellent product call the Deluxe
Option Board that can literally copy, completely, physically damaged
diskettes (cf. Appendix D)
DISKED page 17
The BOOT sector can be fixed by reading the BOOT of a good disk of the
same format, putting in the corrupted disk and writing the sector. The
DOS FORMAT command will of course fix a disk, but all data will be lost
(although one could press ^Break after the first track is formatted).
The FAT can be written in a similar manner. Just remember to copy from
a disk without files. An empty FAT has a sequence of 3 bytes
indicating the type of format and is then all zeros. The number of
sectors of the FATs is displayed in the drive statistics.
An empty ROOT is filled with zeros. The number of sectors of the ROOT
is the logical sector number of the first cluster minus the logical
sector number of the 'home' position.
DISKED page 18
4.2 Recovering Files
4.2.1 Text Files
Getting back text files is basically a hit and miss situation. Knowing
some of the text helps by searching for it. If not, ranging, or paging
over the disk is the only way. Once a sector with data to be recovered
is found, search back to the beginning of the data and then do a 'g1'
to get the rest of the track.
Display the file buffer to find out how many sectors should have been
read in. By the correct number of 'u's, or an 'e' followed by a 'gn'
with the correct number of sectors, a good chunk of data can be
retrieved. If the data extends beyond a track, more data can be
retrieved by a '^N' (or pgdn) followed by a 'g0'.
If the data is very fragmented, range by the 'r' command, stopping and
appending as needed. Since DOS stores file data by clusters, it may be
more efficient to move a cluster at a time.
If large amounts of data are to be recovered, always put the file
buffer to another disk to avoid overwriting recoverable data.
Understanding the beginning byte sequence of formatted files and
worksheet and database files will give something to search for. A
little investigation of files can provide this information.
4.2.2 Executable Files
Executable files can only be recovered if the size is known and the
file is contiguous. EXE format files provide the size information.
COM files and overlays do not. In an EXE file, the fourth and fifth
bytes of the file contains the file size in 512 byte pages. The number
is in hexadecimal and stored least significant byte first. For example
17 00 shows that the file is 17 pages long not 1700. Since a sector is
512 bytes long this makes recovering the file by getting that many
2
sectors .
Also, the first two bytes of all EXE files is 4d 5a (hex), which is MZ
in ASCII. This enables the finding of the beginning of the EXE file.
If the recovered EXE file results in the DOS message "ERROR in EXE
file" (or if it hangs the system) then the file was not contiguous or
was corrupted.
_______________________________________________________________________
2. More sectors than are needed may be saved and the program will run
correctly.
DISKED page 19
4.3 Other Uses
Another well suited use for DISKED is the changing of messages that a
program displays. If many copies of a program are being distributed,
each copy having a unique serial number or message, DISKED can be used
to go to that particular sector holding the information, change data
and then to write the sector. This takes the place of multiple
compilations or expensive serialization programs.
This is further speeded up by making multiple floppies containing just
that one program, and setting to the appropriate sector once, make the
change, write the sector, put in the next disk, make the change, write
the sector, and so on.
DISKED is the only program that allows this kind of work to be done (at
a reasonable price!).
DISKED also lets you investigate and create small files containing
codes outside ASCII values.
DISKED also lets you edit a file without an editor.
DISKED page 20
Section 5
An Example of Usage
C:>disked a:
Serial No: 1.NF3.011 DOS: 3.3
buffer size: 16384 number of drives: 4
current drive: A: media: IBM 3.3
volume label: ? current directory: \
drive size: 363520 cluster size: 1024
sector size: 512 total sectors: 719
sectors/fat: 2 sectors/cluster: 2
sectors: 1-9 tracks: 0-39
clusters: 0-355 heads: 0-1
'/' for help
track 0, sector 6(5), head 0
00000: 44 45 4d 4f 20 20 20 20 45 58 45 20 00 00 00 00 DEMO EXE ....
00016: 00 00 00 00 00 00 74 8a c9 14 02 00 04 00 00 00 ......t.........
. . .
00096: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00112: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
(00000)*s track b
track 0, sector 1(0), head 0 BOOT
00000: eb 34 90 49 42 4d 20 20 33 2e 33 00 02 02 01 00 .4.IBM 3.3......
00016: 02 70 00 d0 02 fd 02 00 09 00 02 00 00 00 00 00 .p..............
. . .
00096: 1a 7c 88 16 2a 7c a3 39 7c c3 b4 02 8b 16 39 7c .|..*|.9|.....9|
00112: b1 06 d2 e6 0a 36 3b 7c 8b ca 86 e9 8a 16 fd 7d .....6;|.......}
(00000)*a append sector
(00512)*^P file: boot.rec put file w/o options? Yes putting
(00512)*. exit DISKED? Yes
C:>
The above example saved the BOOT record of the diskette in drive A: to
the disk so it could be investigated by a debugger or disassembled.
DISKED page 21
Section 6
Command Summary
6.1 Movement
n,N,^N next sector, cluster, track
b,B,^B back sector, cluster, track
st,s,h set to track t, sector s, head h
Sn set to cluster n
^Sn set to logical sector n
sb set to BOOT sector
sf set to FAT sector
0-9 set to tagged sector 0-9
home set to root directory
end set to last sector
r range forward by sectors
^R range backward by sectors
R range forward by clusters
j jump to next cluster of file
J jump to previous cluster of file
^right set to the next un-allocated cluster
^left set to the previous un-allocated cluster
6.2 Get
a append sector
A append cluster
^An,n append from n, n bytes
g0|1|n get sectors
^G0|1|n get sectors with move
6.3 Unget
u unappend sector
U unappend cluster
^Un unappend n bytes
e empty
6.4 Log
lD log disk D
^L re-log disk
6.5 Search
fs find string s on disk
DISKED page 22
^Fs find s searching backward
Fs find s in file buffer
6.6 Display
SPACE dump sector buffer
dn dump file buffer from n
vn view file buffer from n
^V view sector buffer
BS display disk parameters
/ display command summary
m display cluster map of current file
M map un-allocated clusters of drive
Shft-F1 top 128 bytes of sector buffer
Shft-F2 full sector buffer
Shft-F3 view sector buffer
Shft-F4 directory display of sector buffer
6.7 Change
cn change sector buffer from n
Cn change file buffer from n
^C change directory
k kill changes
6.8 Files
ps put file buffer to file s
^Ps put with no translation to file s
Pn,n,s put from n, n sectors to file s
is insert file s
^Is insert file s with no translation
6.9 Miscellaneous
zs change parameters
Z display parameters
, toggle input radix
F1 display files in current directory
F2 display all files on disk
F3 display number of files and directories
F4s change to directory s
F5 re-read sector
F6 append sector with 'strip'
F7 append sector with 'convert'
F8 append sector with 'mask'
F9 append sector per translation keywords
DISKED page 23
F10s set to the first sector of file s
tn tag sector n
T display tagged sector list
x view DISKED.INI
X view DISKED.SAV
^X save state
^Z restore state
DISKED page 24
Section 7
Error Messages
Most errors will be harmless and can be considered warnings. DOS
errors will be common on damaged diskettes. The file buffer and spare
buffer contents are always maintained until explicit commands empty
them.
Messages
Invalid Boot Sector D: Cannot run.
DISKED was able to read but not able to interpret the boot sector
of the current drive. Select another drive or disk and try
running DISKED again.
Invalid Boot Sector D: Use current?
DISKED was able to read but not able to interpret the boot sector
of drive designated on the command line. A Y will use the current
drive, any other key will exit.
Drive Not Ready D: Use current? (or Retry)
DISKED cannot access the drive designated on the command line,
usually because the drive door is not closed or the disk is
physically damaged. A Y will use the current drive, an R will
retry drive D:, any other key will exit.
General Failure D: Use current?
DISKED cannot read the drive designated on the command line,
usually because the disk is not formatted or a format that DOS
cannot read (such as a 1.2/1.4M disk on XT machines). A Y will
use the current drive, any other key will exit.
Insufficient Memory, n
There was not enough memory available for storing the cluster
numbers for the particular disk, where n is the number of
clusters. The 'files' keyword will be turned off. There was not
enough memory for holding the FAT sectors in memory, where n is
the amount of memory needed.
FAT Entry Invalid, n=x
The offset n into the FAT area is not valid. Indicates a corrupt
FAT.
"filename" Starting Cluster Number Invalid
DISKED page 25
The starting cluster number for the directory entry "filename" is
not a valid cluster number. Indicates a corrupt directory.
Create File Error
DISKED could not create the file for saving the file buffer.
Could indicate to many files in the root directory. Has no effect
except no file is written.
Write Error
DISKED could not write data to the file saving writing the file
buffer. Most likely this will be due to not enough disk space.
Has no effect other than a file that may not hold any or all data.
Data Error (CRC)
Seek Error
Sector Not Found
DISKED encountered a damaged sector. The bad sector will still be
selected although the sector buffer will contain the last read
sector's data (or garbage). Any command that was in progress will
be stopped.
DISKED page 26
Appendix A
Anomalies
Anomalies are strange functionings that will require too complicated
programming to adjust, or aspects of DOS that DISKED cannot overcome.
The following is a list of such phenomena.
fs The string can contain null characters (a value of zero)
by a \0 embedded in the string. If the first byte is a
\0, then the next call to 'f' cannot be repeated with just
a return.
The string to be searched for will not be found if it lies
across sector boundaries so keep search strings as small
as possible. This may be changed if I see a need for it.
sb|sf In hex mode, an sb and an sf will still set to the BOOT
and the FAT. Use a leading 0 to avoid this.
Some non-DOS floppy disk formats will be able to be read if they are
formatted for 512 byte sectors. DISKED will read them properly but not
be able to determine the correct number of sectors the disk has. There
are many shareware utilities to read and write non-DOS diskettes. A
future version of DISKED may provide a way to use non-DOS diskettes if
the need arises.
DISKED page 27
Appendix B
Legal Stuff and License Agreement
This text is a legal agreement between you, the licensee, and me, the
program developer. By using this program, you are agreeing to abide by
the terms of this agreement. If you do not agree with the terms of
this agreement, promptly return the disk package (or erase it, or give
it away, or do not use it).
I grant to the licensee the non-exclusive right, without right to
sublicense, to use this copy of DISKED software on any number of
computers at any time, and to make as many copies of said software as
seems fit, and to freely distribute said software so long as a fee is
not taken for the program for any reason including but not limited to
*
media costs and copying time , with the exception of barter type goods
including other shareware and public domain software.
The software and accompanying documentation (magnetic or paper) are
provided "As Is" without warranty of any kind, expressed or implied
(although registered users will get free future versions and support).
In no event shall the program developer be liable for any loss of
profit or any other commercial damage, including but not limited to
special, incidental, consequential or other damages. In no event shall
any other person offer a warranty of any kind, nor shall any other
person offer support for the use software unless a fee, of any kind, is
waivered.
DISKED can be customized for anyone who requests it. Please send bug
reports, suggestions, criticisms, thoughts, to:
Gregg Jennings
PO BOX 200
Falmouth, MA 02541-0200
(508) 540-9711
_______________________________________________________________________
* If you are willing to share this program with others for the
sole reason of being monetarily compensated, you have no right
to be even using it, PERIOD.
DISKED page 28
Appendix C
Programming Notes
DISKED is NOT another utility CLONE. It was first developed around
1982; I have not tried to copy any other program; DISKED was for my own
use exclusively. I realize now that it may be useful to others.
DISKED uses DOS for all disk reads and writes, for all drive parameter
information, and for all console I/O. DISKED does not perform any BIOS
calls; only DOS interrupts are used with the purpose in mind that it
should work under any standard DOS system (it has been tested on MS-
DOS, PC-DOS, and Compaq-DOS). Although this may not be the fastest or
the neatest way for coding this kind of a program, it is the most
reliable.
The reason for displaying only the first 128 bytes of each sector is
two fold. First, the CP/M operating system had only 128 byte sectors
and DISKED was developed on CP/M. Secondly, the displaying of data 16
bytes per line, in hex followed by ASCII is the display format that I
first saw when I became involved in computers so long ago and the whole
sector will not fit entirely on the screen in this format. A DOS
directory is also better displayed in this format for each file's entry
is 32 bytes in length (which is not just a coincidence).
If any user encounters anything that may be a bug, or any errors in the
operation of DISKED, a written letter to the address found above will
be appreciated. If DISKED was found on a BBS, a message left there
will be appreciated as well.
DISKED was first conceived and developed on what is called an S-100 bus
computer using the CP/M operating system as a very basic sector
oriented diskette editor for used for getting back a file's data after
it's directory entry had been somehow lost (something that happened
fairly often in those early days), and the file could not be "un-
erased" (and since DOS was modeled after CP/M, this still holds true).
Special thanks must be given to someone by the name of Ward
Christensen, whose CP/M program called DU, for Disk Utility, gave me
the basics of low level diskette I/O to relate to. DU was (and still
is if anyone has a CP/M machine) a neat utility for reading, modifying
and writing diskette sectors. It lacked, however, a way of saving
diskette sectors to a file.
DISKED is growing almost daily; new features are being added on the fly
for I am constantly finding more uses for it. If you are seriously
using this program, your thoughts and criticisms will be listened to at
this time -- I will seriously consider additions and changes.
DISKED page 29
Appendix D
Other Utilities
List of recommended commercial utilities. There are not many, but I
will update the list as I gather more information. If anyone has there
own useful utilities a note sent to me will be appreciated.
Copy II Pc (R) Deluxe Option Board by Central Point Software.
This is an add-in board for PC-XT's which is meant for Apple, Amiga and
Atari floppy conversions as well as copy protected backups. It comes
with a really cool floppy disk editor of an unprecedented level -- it
lets one view and edit stuff like the Gap and Sync bytes, Sector IDs,
and all of the "real" data on the disk. It also explains what all that
stuff is. I have used it to successfully copy physically damaged
diskettes. I forget the price but it was worth it.
Spinrite by Gibson Research
Spinrite will actually repair bad sectors on a hard drive. I do not
know how they can do this I swear it works. It can take a long time --
5-10 hours -- but can be interrupted and started ^LPage 2 again later
where it left off.
Contents
WHAT DISKED IS . . . . . . . . . . . . . . . . . . . . 2
WHAT DISKED IS NOT . . . . . . . . . . . . . . . . . . 2
REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . 2
TUTORIAL . . . . . . . . . . . . . . . . . . . . . . . 3
1 Using DISKED . . . . . . . . . . . . . . . . . . . . 4
1.1 Documentation Notes . . . . . . . . . . . . . 4
1.1.1 Command Input Conventions . . . . . . . . . 4
1.1.2 Keyboard Input . . . . . . . . . . . . . . . 5
2 Commands . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Drives . . . . . . . . . . . . . . . . . . . . 6
2.2 Moving . . . . . . . . . . . . . . . . . . . . 6
2.3 Editing . . . . . . . . . . . . . . . . . . . 7
2.4 Copying . . . . . . . . . . . . . . . . . . . 9
2.5 Storing . . . . . . . . . . . . . . . . . . . 10
2.6 Files . . . . . . . . . . . . . . . . . . . . 10
2.7 Displaying . . . . . . . . . . . . . . . . . . 11
2.8 Searching . . . . . . . . . . . . . . . . . . 11
2.9 Exiting . . . . . . . . . . . . . . . . . . . 12
2.10 Miscellaneous . . . . . . . . . . . . . . . . 12
3 DISKED Initialization . . . . . . . . . . . . . . . 14
3.1 DISKED Keywords . . . . . . . . . . . . . . . 14
3.2 Changing DISKED Parameters . . . . . . . . . . 15
3.2.1 Outside DISKED . . . . . . . . . . . . . . . 15
3.2.2 Inside DISKED . . . . . . . . . . . . . . . 15
4 Hints on Usage . . . . . . . . . . . . . . . . . . . 16
4.1 Bad Sectors . . . . . . . . . . . . . . . . . 16
4.1.1 Damage . . . . . . . . . . . . . . . . . . . 16
4.1.2 Corruption . . . . . . . . . . . . . . . . . 16
4.2 Recovering Files . . . . . . . . . . . . . . . 18
4.2.1 Text Files . . . . . . . . . . . . . . . . . 18
4.2.2 Executable Files . . . . . . . . . . . . . . 18
4.3 Other Uses . . . . . . . . . . . . . . . . . . 19
5 An Example of Usage . . . . . . . . . . . . . . . . 20
6 Command Summary . . . . . . . . . . . . . . . . . . 21
6.1 Movement . . . . . . . . . . . . . . . . . . . 21
6.2 Get . . . . . . . . . . . . . . . . . . . . . 21
6.3 Unget . . . . . . . . . . . . . . . . . . . . 21
6.4 Log . . . . . . . . . . . . . . . . . . . . . 21
6.5 Search . . . . . . . . . . . . . . . . . . . . 21
6.6 Display . . . . . . . . . . . . . . . . . . . 22
6.7 Change . . . . . . . . . . . . . . . . . . . . 22
6.8 Files . . . . . . . . . . . . . . . . . . . . 22
6.9 Miscellaneous . . . . . . . . . . . . . . . . 22
7 Error Messages . . . . . . . . . . . . . . . . . . . 24
Appendix A Anomalies 26
Appendix B Legal Stuff and License Agreement 27
Appendix C Programming Notes 28
i
Appendix D Other Utilities 29
ii
Tables
Table 2.1: Change Formats . . . . . . . . . . . . . . . . .8
Table 2.2: Directory Change . . . . . . . . . . . . . . . .8
Table 2.3: Find Control Charcters . . . . . . . . . . . . 12
iii
