myrescue-bitmap2ppm - Visualisation of the block bitmap for myrescue
myrescue-bitmap2ppm bitmap-file width [ rows width ] ...
myrescue-stat reads a block bitmap from
myrescue(1) and generates a
visualisation of each blocks condition.
The image is written to stdout in
PPM(5) format. You can pipe the output into
one of the netpbm converters or into
ImageMagick(1) to convert it to a more
common format like PNG.
Successfully copied blocks are shown as green pixels. Yellow-green-ish pixels
indicate blocks that could be copied, but it took unusually long, indicating
that this area might be near-failing. Yellow blocks have been tried once, but
could not be read, red blocks could not be read on multiple attempts. Black
pixels indicate blocks that have not yet been handled.
The pixels are arranged left-to right, with the first block in the upper left
pixel. The width of the image must be specified on the command line - just
pick any value.
In case of partially defective discs you might start by having myrescue do a
random jump-around scan (option
-J) and continually check the
visualized block bitmap. If you are lucky, you might begin to see some
structure in the image. If these structures somehow run diagonally, you can
adjust the width until you get vertical stripes of defective areas. What this
means depends on the internal layout of the disc, but it could be defective
heads, platters, sectors, cracks, a factory workers hair, ...
Usually internally discs have different zones, so after a few (hundred?) rows
you might see the vertical structures bend off. To adjust the image, you can
tell the tool to switch to a different width after a certain number of rows.
Repeat this until you identified all zones. The last width will be used up to
the end of the bitmap.
The resulting image will have the maximum width necessary to accommodate all
zones. Zones with shorter widths will be padded on the right with blue pixels.
You can now use this information to manually fine-tune the myrescue calls to
concentrate on areas with higher probability of rescue.
Kristof Koehler <
[email protected]>
myrescue(1),
ppm(5),
ImageMagick(1)
http://myrescue.sourceforge.net/