Reading difficult disks (Wabash, etc.)
An a half-way update, the procedure based on advice received in this forum thread has been working effectively.
Definition of ‘working effectively’:
- To recover data from floppy disks in a single read, leaving the disk in a sound condition that allows further reads.
Some disks have been found to be unformatted, blank or to have had all original files deleted. In many cases, disks have been read with a number of bad sectors.
The initial read allows bad sectors to be identified. It is envisaged that further attempts will be made to re-read the tracks on which bad sectors were identified. An obvious step for re-reading would be to use a different drive, where the head alignment may be slightly different.
It has famously been said of advertising: “We know that half the money we spend is wasted, but we don’t know which half is wasted”.
Similarly, it is possible that some of the steps adopted were unnecessary – in the sense that the key benefits came from ‘other’ steps in the process. The potential wastage is of time, rather than money.
However, I’ll continue to use – and recommend - the procedure outlined here:
- Identification of the disk – assigning a label. Using white permanent ink to write the disk number on the inner part of the disk, on the side with the label on the sleeve.
- Removal of the disk from the original sleeve.
- Washing in hand-heat water with a small amount of a mild detergent, with rinsing in a larger container of somewhat hotter water.
- Air drying, with removal of drops using a non-linting soft cloth,
- Baking at 40-57 C degrees for 4 hours or more
- Coating the oxide surfaces on both sides with cyclomethicone (which is a clear fluid, commonly used in skin and hair products. It evaporates in a matter of minutes leaving the treated surface about the same as prior to application).
- Placing the disk in a fresh sleeve with index hole in double-sided position
- Reading tracks on both sides in a series of stages: 0-4, 5-14, 15-24, 25-34, 35-54, 55-76. At each stage, wipe the drive heads with a swab soaked in Isopropyl Alcohol – even if there is no apparent shedding of oxide on the drive heads.
- A series of logfiles is saved, each with the results of one of the stages above.
- The flux transition data is loaded in HxC Floppy Emulator software, which is used to view the resulting data as an image of each disk surface. This identifies the encoding (FM or MFM) as well as the number of sectors and the number of bad sectors.
- The data is exported as IMG and IMD files, for inspection in a HEX viewer.
What are the indicators that the multiple steps of the procedure have been effective?
- No disk has been damaged – for example with significant amounts of oxide left on the drive heads, and concentric grooves left in the oxide surface,
- No build-up of oxide on the drive heads has been observed.
- Every disk has resulted in data that can be viewed in a HEX viewer, although this does not necessarily represent the entire data originally written.
- The HEX viewer has enabled the OS and its version to be identified and the directory to be examined.
- The same procedure has been suited to single and double-sided disks in a number of different formats and encoding schemes.
One potential time saving would be to read only side 0 of disks labelled ‘single-sided’ and in a disk sleeve with the index hole marking the disk as single-sided.
Question: is there any computer system / OS that would allow an 8-inch disk to be written on both sides when the position of the index hole in the sleeve marks it as single-sided?
I envisage providing further documentation on completion of reading the other half of the collection of disks. I have found a convenient batch size to be around 7 disks.
An a half-way update, the procedure based on advice received in this forum thread has been working effectively.
Definition of ‘working effectively’:
- To recover data from floppy disks in a single read, leaving the disk in a sound condition that allows further reads.
Some disks have been found to be unformatted, blank or to have had all original files deleted. In many cases, disks have been read with a number of bad sectors.
The initial read allows bad sectors to be identified. It is envisaged that further attempts will be made to re-read the tracks on which bad sectors were identified. An obvious step for re-reading would be to use a different drive, where the head alignment may be slightly different.
It has famously been said of advertising: “We know that half the money we spend is wasted, but we don’t know which half is wasted”.
Similarly, it is possible that some of the steps adopted were unnecessary – in the sense that the key benefits came from ‘other’ steps in the process. The potential wastage is of time, rather than money.
However, I’ll continue to use – and recommend - the procedure outlined here:
- Identification of the disk – assigning a label. Using white permanent ink to write the disk number on the inner part of the disk, on the side with the label on the sleeve.
- Removal of the disk from the original sleeve.
- Washing in hand-heat water with a small amount of a mild detergent, with rinsing in a larger container of somewhat hotter water.
- Air drying, with removal of drops using a non-linting soft cloth,
- Baking at 40-57 C degrees for 4 hours or more
- Coating the oxide surfaces on both sides with cyclomethicone (which is a clear fluid, commonly used in skin and hair products. It evaporates in a matter of minutes leaving the treated surface about the same as prior to application).
- Placing the disk in a fresh sleeve with index hole in double-sided position
- Reading tracks on both sides in a series of stages: 0-4, 5-14, 15-24, 25-34, 35-54, 55-76. At each stage, wipe the drive heads with a swab soaked in Isopropyl Alcohol – even if there is no apparent shedding of oxide on the drive heads.
- A series of logfiles is saved, each with the results of one of the stages above.
- The flux transition data is loaded in HxC Floppy Emulator software, which is used to view the resulting data as an image of each disk surface. This identifies the encoding (FM or MFM) as well as the number of sectors and the number of bad sectors.
- The data is exported as IMG and IMD files, for inspection in a HEX viewer.
What are the indicators that the multiple steps of the procedure have been effective?
- No disk has been damaged – for example with significant amounts of oxide left on the drive heads, and concentric grooves left in the oxide surface,
- No build-up of oxide on the drive heads has been observed.
- Every disk has resulted in data that can be viewed in a HEX viewer, although this does not necessarily represent the entire data originally written.
- The HEX viewer has enabled the OS and its version to be identified and the directory to be examined.
- The same procedure has been suited to single and double-sided disks in a number of different formats and encoding schemes.
One potential time saving would be to read only side 0 of disks labelled ‘single-sided’ and in a disk sleeve with the index hole marking the disk as single-sided.
Question: is there any computer system / OS that would allow an 8-inch disk to be written on both sides when the position of the index hole in the sleeve marks it as single-sided?
I envisage providing further documentation on completion of reading the other half of the collection of disks. I have found a convenient batch size to be around 7 disks.
