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- HOW TO FORMAT A DMF-FORMAT DISK
- -------------------------------
-
- Microsoft has begun using an oddball 21-sector format on its
- program distribution 3 1/2" floppy disks which they call
- High-Density DMF. (Examples are Microsoft Word 6.0c and
- Microsoft Excel 5.0c) These DMF-format floppies cannot be
- copied or duplicated with any conventional DOS commands; all
- you can do is install from them - if the floppies are
- trouble-free!
-
- I like to have backup copies of all my original program disks.
- I think it's just a wise thing to do. Floppies can go bad
- and it's good to have a backup set of original program disks
- if they are ever needed. So, the new DMF-format floppies
- presented a real challenge in order to make a backup set
- of disks.
-
- A nifty little public-domain program, FDFORMAT, lets users
- manage DMF-format floppies with ease. Though FDFORMAT and its
- associated FDREAD tsr are in the public domain, and no fee is
- requested, a thank-you to Christian Hochstatter, the coder
- from Marburg, Germany, who developed it, wouldn't hurt. His
- postal and e-mail addresses are in the FDFO.ZIP package.
-
- DMF-format disks came along after FDFORMAT was written.
- Therefore, FDFORMAT does NOT explicitly support formatting
- a DMF disk with its supplied /F parameter options. After a
- little experimentation, I found the proper command line
- parameters to use in order to format a DMF disk.
-
-
- The command to format a DMF-format 3 1/2" disk is:
-
- FDFORMAT /T:80 /N:21 /C:4 /D:16 /M:240
- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
- This will yield the following results from FDFORMAT after
- the disk is formatted:
-
- --------------------------------
- OEM-Entry CH-FOR16
- Total sectors on disk: 3360
- Sectors per track: 21
- Heads: 2
- Bytes per sector: 512
- Hidden sectors: 0
- Boot-sectors: 1
- Number of FATs: 2
- Sectors per FAT: 3
- Total clusters on disk: 838
-
- 1716224 total bytes on disk
- 1716224 bytes available
- --------------------------------
-
- The key is the /M:240 parameter. This sets the Media Descriptor
- Byte to F0 (hex). This allows FDFORMAT to successfully use
- 4 sectors per cluster on a floppy disk. DOS normally supports
- only 1 or 2 sectors per cluster as the FDFORMAT documentation
- explains. Without this parameter, and using 4 sectors per cluster
- (/C:4), FDFORMAT will incorrectly set the Media Descriptor Byte
- to F8 (hex) and the disk will NOT be properly read by DOS.
-
-
- After formatting your DMF-format floppies, the original program
- disk files can be copied to the DMF-format backup floppies.
-
- ** Be sure to also use the LABEL command to label each backup disk
- with the appropriate label from each original disk! **
-