ATARI CHKDISK3 DOCUMENTATION
April 22, 1990
WARNING!! CHKDISK3 has not been through heavy testing and you use
this program at your own risk. Proceed with caution. Back up your
disks (especially hard disks) BEFORE you use CHKDISK3. This is a
powerful tool which can fix damaged disks, but if it's misused,
it can also damage good disks.
The Atari CHKDISK3 program is a utility that analyzes a
disk's file structure and does all of the necessary fixes. Before
you use the program, you should have some basic knowledge about
the disk and file structure.
On the surface of each disk are invisible rings called
tracks. The number of tracks on a hard drive depends on the size
an type of the drive. A blank disk must be formatted in order to
create these tracks. Each track is divided into many small
fragments called sectors. Each track has sectors. Several sectors
linked together are called a cluster. Directories and files are
stored into data clusters. Some files may occupy one cluster and
some may occupy more depending on the size of each file. To keep
track of the status of each cluster, the disk contains a structure
called a File Allocation Table (FAT). The FAT records which clusters
are in use, which ones are free and which ones are physically
damaged. A cluster which is logically allocated but has no file
actually using it is called a "Lost Cluster". A cluster which is
shared by two or more different files is called a "Doubly Used
Cluster". A damaged cluster is called a "Bad Cluster".
USING CHKDISK3
You must specify the drive id and pathname for some options. Here
are descriptions of all of the functions:
FILE:
* Edit File
Use this function to edit the clusters containing the
current file.
Att = Attributes ORing the following values:
x00 normal file
x01 read only
x02 hidden from directory search
x04 set to system, hidden
x08 eleven-byte volume label
x10 subdirectory
x20 archive bit set
Clusters = the number of the starting cluster
* Analyse FAT
This function scans through the disk and checks all of the
clusters' allocation information. If it finds any Lost, Doubly
Used, or Bad clusters, they are shown by using three different
lines. The actual clusters number can be checked by clicking the
arrows to scroll the window. Any Lost cluster can be recovered
immediately by clicking the [Recover] button. Doubly Used
clusters mean that the disk is logically damaged. Back up the
disk (or partition) immediately and use HDX to reformat it.
* Show FAT map
Show clusters' allocation map. On a colour monitor, different
colour dots indicate non-contiguous clusters.
* Compress Disk
This function compresses the current disk and frees up any
Lost clusters. The Disk is compressed by removing empty clusters
between allocated clusters. This function first analyzes the
disk, then a second box comes up for the final confirmation.
There is a percentage-completed chart to inform you about the
progress of the compression. If the disk is badly fragmented, it
may take a long time to do the compression.
Warning! Do not attempt to change the disk while inside this
function.
* Edit FAT table
Allows you to edit the cluster links of the FAT table.
* Edit Disk Sectors
Edit any sectors. The data is shown in hexdecimal form.
F1 - Drive/Unit. Drive: a-z. Unit: 0-9
F2 - Logical sector number to edit
F3 - Absolute sector to edit
F4 - Use the second FAT
F5 - Edit root directory
F6 - Go to previous sector
F7 - Go to next sector
F8 - Save edited sectors
F9 - Hex or decimal input of sector number
F10- Exit
MISC
* Force Media Change
Force CHKDISK3 to read in the BPB again. This is useful
after editing the FAT or sectors.
* Help
Show the help menu
-- NOTE ---- NOTE ---- NOTE ---- NOTE ---- NOTE ---- NOTE ---- NOTE --
Use this program at your own risk and take it 'as it is'.
This program is not Public Domain (Atari owns the rights) but you may
upload it into other Mailboxes and as long as you don't ask money for
it and you don't edit/patch it.
Wilfred Kilwinger
Support Manager
Atari Benelux,
International Support Center