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The directory keeps track of a files TYPE. A code file
is EA32 (hex). When the file is moved (via ftp) and it
happens to be a code file, BD (via FACSNet and maybe FACSlink)
changes the file type to prevent license violations, I suppose.
If you can edit the directory area on a diskette (HP LIF variety)
the change can be made.
The first 512 bytes of the pre-directory area is the volume header
and the directory follows. Within the confines of each 256 byte
block of the directory, there will be at most 8 entries. The
first 10 bytes of each entry is the filename (thus the limitation
of LIF for a 10 character filename). The next two bytes is the
file TYPE. If you change the TYPE to EA32 from whatever it is,
you're home free. If you come across a file type of 0000, this
is an erased file which is also handy to know if you accidentally
erase a file and want to get it back (provided you haven't written
anything to the media meanwhile). Changing it to the correct type
will restore it to the file system. If you come across a file type
of FFFF, this indicates the last entry in the directory (no need to
look further) and the filename is usually all zero's or blanks
(2020). It's possible you may not come across FFFF if you have the
maximum number of files stored on the media (default of 80 unless
you changed the default using the Zero option under Filer).
For the record, EA3E is TEXT, EA0A is DATA and E942 is SYSTem.
I would suggest that these changes not be done to a file
stored on HFS media, so transfer the file(s) to a diskette first,
which is LIF. LIF is sequential (volume header, directory and
data area all laid out like ducks in a row) but HFS directories
are scattered all over the media as well as the files themselves
which is one of many reasons I always advise users to revert back
to LIF on any removable type of media like Bernoulli or optical
cartridges. There is three times the head movement on any HFS
initiated I/O compared to LIF and this contributes to the earlier
demise of media and drive as well as poorer performance. HFS
also consumes 180K bytes of disk space for every megabyte of disk
capacity for overhead use. LIF has no overhead of this nature.
Removable media in HFS is sensitive to corruption problems and I
have provided a data recovery service to BDIS for the past several
years because of this.
I have format procedures to create LIF volumes (single 20M volume
on Bernoulli, ten 32M volumes on optical and various combinations
for hard drives depending on the capacity of the drive). If anyone
is interested just contact me.
************************************************************
* FLOW CYTOMETRY SUPPORT *
* Richard A. Cox *
* PO Box 3450 *
* Saratoga, CA 95070-1450 *
* *
* Voice: 408.370.6327 *
* email 2359766@mcimail.com *
* FAX: 408-370-6487 *
************************************************************
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