
		      BD BAD DISK PROGRAM
		      ===================

GENERAL:
-------
'BD' stands for "bad disk".  It reads the records on a disk (floppy or
hard) and finds those that are unacceptable.  It locks out the blocks
containing those records into a file called [LOCKED].OUT.  It then shows
what files (if any) are defective.  (The program is 5k long.)

Small floppies have blocks with 8 records (1k), larger floppies have
blocks with 16 records (2k) and most large hard drives have blocks with
32 records (4k).

'BD' has a progress report by showing the current block count, each five
blocks.  If/whenever a block has one or more bad records, this informa-
ion overwrites the progress report.  It then resumes the progress report
on the following line.

This gives an attractive display.


EXAMPLE 1:
---------
If the disk already has a [LOCKED].OUT file from a previous check, the
results might look like this:


		BD v01 - bad disk blocks/files

		check drive: A	      (automatically logs in that drive)
		checking....

		prior check: 127
		prior check: 148
		prior check: 149
		prior check: 160
		 this check: 162
		prior check: 204
		 this check: 225

		494		      (total data blocks checked)

		bad blocks: 7

		bad files:

		A:CRT	  ASM
		A:LIST	  DOC

		A>


As it checks the file, if the current block has previously been reported
as bad, that is shown as "prior check", and if not previously reported,
it shows as "this check".  Thus you can see if the disk has new problems
since the prior check.	You can manually erase the [LOCKED].OUT file if
you wish and rerun the program to see what it will report "this time".
(If results vary more than slightly, you may have a bum drive that is
giving erratic results, or that initially did a poor job formatting the
disk.)

When showing 'bad files' it may show the same file name more than one
time, indicating that particular file has multiple bad areas and will be
difficult to rebuild into a normal file.


EXAMPLE 2:
---------

This is what you are hoping to see, for a normal disk:


		BD v01 - bad disk block/files

		check drive: B
		checking....

		494

		bad blocks: 0
		bad files : 0

		A>

OPTIONS:
-------

    1)	0103h	-   sets the user area for [LOCKED].OUT file.

		    00 = user area zero
		    0F = user area 15

		    (then save 20 pages if using DDT or SID, etc.)

    2)	0105h	-   turns progress reports on/off.  You may want a
		    version with them turned off, so you can use the
		    printer to display the results.

		    00 = no progress reports
		    FF = progress reports shown (anything but 00)


					- Irv Hoff W6FFC


