DATMAN TECHNICAL BULLETIN #009
From: Kan Yabumoto firstname.lastname@example.org
To: DATMAN user
Subject: Reading a non-DATMAN tape
Although DATMAN-99 is designed to be used primarily as a Windows 95/98
file system, it can be used to extract data on a tape written by
a tape software other than DATMAN. For example, if you have a tape
written by TAR (a popular UNIX tape archive utility), you can use
DATMAN to retrieve the data from the tape. At present, DATMAN does
not have any specific knowledge of tape format other than its own.
If you do not have DATMAN-99 on your system, you should first try
the DATMAN Freeware available at http://www.datman.com/dlcent.htm.
Since DATMAN-99 operates with a DATMAN-formatted tape, it expects the
tape to be a DATMAN tape for normal operations. Therefore, before
you insert a tape written by software other than DATMAN to the drive,
you should disable "Auto-Mount" by [ Settings > Advanced_Settings ],
and avoid accessing the tape via the drive letter (which would also
initiate the mount-on-demand actions. Once you let DATMAN attempt to
mount the catalog from the tape, it may spend an inordinate amount
of time to search and locate the non-existent catalog on the tape.
This is due to the fact that DATMAN is designed to cope with a badly
damaged tape and try everything it can to recover user files from the
tape. Therefore if you are trying to read data from a non-DATMAN tape,
it is extremely important that you do not let DATMAN initiate its
catalog-mount operation. First, disable the Auto-Mount feature, and
never try to access the tape from the drive letter. Since Windows
Explorer (and also possibly other programs) periodically updates its
windows which may trigger a drive letter-based directory access to
the tape (which in turn requests DATMAN to initiate a catalog-mount),
you should terminate Explorer (and similar utilities) before you
start this procedure to avoid any trouble.
The following DATMAN commands are useful with a non-DATMAN tape.
[ Scan > Scan_Blocks ] to preview a few selected blocks
[ Scan > Scan_Sizes ] to determine block sizes
[ Scan > Scan_Marks ] to scan quickly the entire tape for marks
[ Retrieve > Get_Blocks ] to perform the actual data retrieval
DATMAN can retrieve data with any block size up to 64 KB. The most
important command is the [ Retrieve > Get_Blocks ] command which
allows you to retrieve the raw data from the tape on a byte-by-byte
basis. You specify a range of blocks on the tape and DATMAN will
read the tape and create a binary file on the disk. It also has a
hex-dump mode which is useful for examination.
Since DATMAN is not intended to be a utility to extract data which
were written by a non-DATMAN program, it is up you to perform any
necessary data processing. DATMAN simply creates a file on the
disk which corresponds data on the tape. In the case of TAR files,
there are a number of utilities including the popular shareware,
WinZip (Please do not ask as questions about WinZip).
A number of users requested us to support other popular tape formats.
At this point, we do not have plans to support proprietary non-DATMAN
tape format such as DTA and TapeDisk. We believe none of these
formats are as robust as DATMAN's. We have heard many horror
stories that user files have been lost using these tape utilities.
We believe our engineering resource should be focused on improving
the DATMAN products.
Generally speaking, if data is written by Brand X software, it
should be read by the Brand X software. This is especially true
with proprietary formats. In the future, we may support the TAR
format because the format is well documented and published.
If you have a large number of DTA/TapeDisk tapes, we suggest using
two tape drives to transfer files from the other file system to