On what kind of machines will you use this bootable CF card?
Do you plan to dd the images from what source, the same card running linux, network?

I used a similar technique several times to clone a disk from a retro system.
But I booted a lightweight Linux instead (from cd). CF will work too.

You can DD to a file, but also through the network (using netcat)
And md5sum is used to check that the saved image is identical to the physical disk.

Thanks. I am using a ESA TF486 baby AT, has post DOS features such as Plug'n Play. I have no OS installed. Using a Samsung Voyager 2 3.4 GB HDD from 1997 and a Promise U33 PCI with an option ROM to over come the defunct INT13h from Phoenix BIOS.

A virtual machine disk with DOS installed is ascribed to a CF card. The host is Windows 11. The VM running a live Linux ISO in its CD drive will then image it's hard disk drive. This is later the resulting file can be stored on a single CF with debian. I can then use a single CF reader on my 486 to reverse dd onto my mechanical hard drive.

acl wrote on 2023-05-26, 19:14:

I used a similar technique several times to clone a disk from a retro system. But I booted a lightweight Linux instead (from cd) […]
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I used a similar technique several times to clone a disk from a retro system.
But I booted a lightweight Linux instead (from cd). CF will work too.

You can DD to a file, but also through the network (using netcat)
And md5sum is used to check that the saved image is identical to the physical disk.

Thanks. This answers my questions. Now just the time it will take to realize it. Plan to break the project into steps. Worst part is of course can be the hardware but also the commands can be a lot.

Not sure about process of configuring repos. Will the package manager be uniquely difficult?

You can also use a one-floppy Linux distro for the purpose, or a multi floppies rescue system, like the slackware boot and root/rescue disks:
Re: Retro OSes for retro computers

lolo799 wrote on 2023-05-26, 20:44:

You can also use a one-floppy Linux distro for the purpose, or a multi floppies rescue system, like the slackware boot and root/rescue disks:
Re: Retro OSes for retro computers

Yes the floppy is a great idea. I was just coming here to ask about weather or not I should use a full version 1.1 debian or a Linux so tiny it fits in a floppy disk image.

Nice to know there are already distributions for the floppy, and old machines. My father and also myself shortly later, installed Slackware on our 386 with Seagate 40 MB hard drive back in 1992/93.

dd is dd is dd, whether you use it from a 1996 Slackware install, a SunOS version or something from a modern Ubuntu.

What is the purpose of comparing bytes?

If you want to just compare a byte range to another byte range you can extract using DD from one offset and then use diff (with the binary flag) to see if it the same as the other.

A better method is to calculate the checksum of one range of bytes/disk image/file/archive and then compare with what you wrote back.

None of what you are listing is new, and has been done many times before. I can assure you it all works!

megatron-uk wrote on 2023-05-27, 19:12:

dd is dd is dd, whether you use it from a 1996 Slackware install, a SunOS version or something from a modern Ubuntu. […]
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dd is dd is dd, whether you use it from a 1996 Slackware install, a SunOS version or something from a modern Ubuntu.

What is the purpose of comparing bytes?

If you want to just compare a byte range to another byte range you can extract using DD from one offset and then use diff (with the binary flag) to see if it the same as the other.

A better method is to calculate the checksum of one range of bytes/disk image/file/archive and then compare with what you wrote back.

None of what you are listing is new, and has been done many times before. I can assure you it all works!

Yes, it's not original, but I am trying to apply my familiarity with command line keywords to learn more about programming in the shell.

A comparison can teach me how to find data that was corrupted while trying to build a retro computer.

Thanks for sharing some of these methods of using the dd program to compare bytes.

If you plan to boot Debian on the 486, the last version with 486 support is 5/lenny. The repositories have long since been archived (as has everything older than Debian 10). After installation (remember to install the 486 kernel) you have to change /etc/apt/sources.list to point to the archive repository:

1deb http://archive.debian.org/debian lenny main
2deb http://archive.debian.org/debian-security lenny/updates main non-free

To compare files, you can also use cmp, perhaps with the -b or -l option. It's part of the diff package, along with diff itself. This is an essential package and is installed by default, in fact dpkg warns you if you try to remove it.
Comparing checksums could take noticeably longer on an old machine.

Thank you. This was invaluable. Threw away all the disks I made that were later or earlier than version 5. Will be spared the (always) long search to get the repos working. Thanks.

Just to add, since I've been playing with old Debian installs in recent weeks: If you're doing a net install and you're prompted to manually provide a mirror during that process, simply enter in the two fields:

1archive.debian.org
2/debian/

Then you can make the full changes to sources.list afterwards as described by @jtchip. Took me way too long to figure that out.