Amiga hardware info, help and support with a focus (but not limited to) North American NTSC experiences. Open to all.
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daff

by daff posted Tue Apr 30, 2019 6:17 am

Hi,

You can perhaps retrieve the old datas from your Kickstart disk with a disk repair tool.

An example with the Kickstart Disk 1.0.

Perhaps Olaf Barthel can help here.
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sumfx

by sumfx posted Wed May 01, 2019 6:41 am

Looking back I could of course kick(start) myself for not simply going out and buying another box of disks. Water under a 34 year old bridge I'm afraid. I will throw myself on the Sword of Aragon if it helps.
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intric8
Seattle, WA, USA

by intric8 posted Wed May 01, 2019 8:40 am

Looking back I could of course kick(start) myself for not simply going out and buying another box of disks.


Nah, it's not really that big of a deal in the grand scheme of things. I was talking to one of my friends about it this week and we both agreed that, back then, we both probably would have done the exact same thing.

"This is the old kickstart disk, and here's my new one. I'll just backup the new one on top of the old disk and keep using it - put my new one away as the Master for storage." I can totally see myself doing something like that. 100%
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Zippy Zapp
CA, USA

by Zippy Zapp posted Wed May 01, 2019 8:41 am

sumfx wrote:Looking back I could of course kick(start) myself for not simply going out and buying another box of disks. Water under a 34 year old bridge I'm afraid. I will throw myself on the Sword of Aragon if it helps.

Nah. I would be willing to bet that most people did that back then. Nobody thought, "hey this could be important to geeks 30 years from now." I overwrote my Workbench disks all the time as did most of my friends that were Amiga nuts. It was very common. No-one wanted to run a buggy old version if they could help it.
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Christian

by Christian posted Wed May 01, 2019 3:45 pm

There is no digital means that will recover that original Kickstart from the overwritten disk.

The only hope to get this back would be to record the analog signal from the read/write head as the disk is read. When magnetic data is overwritten, some of the magnetization remains. Think of it as the noise on top of the new signal that was recorded.


One could then subtract the signal from the new data, leaving what ever little amplitude of the overwritten data pattern remains and attempt to reconstruct the overwritten data.
Would this be successful? Most likely not as many years have passed, resulting in magnetic domain realignment. Also, one would have to recover every single bit correctly...
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A10001986

by A10001986 posted Thu May 02, 2019 1:09 am

I think what above meant was to eventually recover data from a previous file system, before dumping a KS image on the first few tracks. On Commodore's KS 1.0 and 1.1 were some historic development files, IIRC.
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LocalH

by LocalH posted Thu May 02, 2019 12:33 pm

A10001986 wrote:I think what above meant was to eventually recover data from a previous file system, before dumping a KS image on the first few tracks. On Commodore's KS 1.0 and 1.1 were some historic development files, IIRC.

If the 1.2 image was DiskCopied, it's possible that was overwritten too. Depends on how 1.2 was written to the disk.
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A10001986

by A10001986 posted Thu May 02, 2019 12:53 pm

Indeed. Very probably a lost cause.
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Bilbobaggings

by Bilbobaggings posted Wed May 08, 2019 6:42 am

What an amazing part of history. I wonder if any developed software can be found. Truly amazing.
Thank you for sharing thid wonderful find.
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Leffmann

by Leffmann posted Thu May 09, 2019 1:08 am

Christian wrote:One could then subtract the signal from the new data, leaving what ever little amplitude of the overwritten data pattern remains and attempt to reconstruct the overwritten data.
Would this be successful? Most likely not as many years have passed, resulting in magnetic domain realignment. Also, one would have to recover every single bit correctly...


It sounds as if just one over-write makes it difficult, even when using forensic techniques, and practically impossible after two over-writes. Makes me wonder if there's any merit to these secure erase schemes that claim you must over-write an HDD three dozen times with zeros, ones, and random data.

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