Dump a Disc With Nothing but a Gotek

You do not need a Greaseweazle to preserve an Einstein disc. If your machine has its internal drive and a Gotek, you already own a sector level disc imager: XtalDOS’s own BACKUP. We checked, sector by sector, in an emulator: a BACKUP copy is identical to the original on all four hundred sectors, including deleted files and the data in sectors no file owns. That is the part a straight file copy loses, and it is where most of the finds on this site have come from. This guide is the seven steps, and what the method can and cannot capture.

What You Need

• An Einstein with its internal drive as drive 0 and a Gotek as drive 1, the usual way round.
• Your System Master, or any disc that boots XtalDOS and has BACKUP.COM on it.
• Our blank 190K disc image, BLANK190.DSK, on the Gotek’s USB stick.

The Seven Steps

1. Make a copy of the blank image for each disc. On the PC, copy BLANK190.DSK onto the stick once, then duplicate it under a name for every disc you mean to dump, for example GAMES1.DSK and WORDSTAR.DSK. Each dump overwrites the image it is written into, so each disc needs its own.
2. Put the stick in the Gotek and your System Master in drive 0, and switch on.
3. Type BACKUP at the prompt. Answer B for backup, 0 for the source drive and 1 for the destination. BACKUP now says “Press ENTER to continue”.
4. Swap the discs before you press ENTER. Take the System Master out of drive 0 and put in the disc you want to dump. BACKUP is already in memory and will not need the master again. On the Gotek, select the image you made for this disc.
5. Press ENTER. The drives run for about a minute. BACKUP reads every track of drive 0 and writes it to the image on the Gotek.
6. “Disc Backed up OK”, then “More (Y/N)?” Answer Y for the next disc, selecting its image on the Gotek first, or N to finish. If BACKUP stops with “Bad Data” instead, answer N, note the track if it says, and keep the partial image: it is still worth sending.
7. Share the files with us. Switch off, take the stick to the PC, and share the image files through our upload page, named after the disc labels, with a line about whose collection they came from. It takes up to forty files at a time and needs no account. The file on the stick is the dump; there is nothing to convert.

If Your Gotek Is Drive 0

Some machines have the Gotek in place of the internal drive. Then the order is the mirror image: boot the System Master as an image from the Gotek, run BACKUP with source 1 and destination 0, and at the “Press ENTER” prompt switch the Gotek to the blank image and put the disc to be dumped in the external drive.

What This Captures, and What It Cannot

BACKUP copies the forty tracks of a standard Einstein disc sector by sector, ten sectors of 512 bytes a track, without reference to the directory. So the copy holds every live file, every deleted file whose sectors have not been reused, the data in sectors no file owns, and the system tracks. That is everything we recovered from the eighty five images a reader sent us this month, from a pre production Space Trap to a disassembly of the DOS.

What it cannot copy is anything that is not in the standard format: sectors numbered outside 0 to 9, sectors of another size, tracks beyond 39, and the contents of sectors whose checksums fail. Those are the tricks copy protected originals used, and a Greaseweazle reading the flux is the only way to keep them. If a disc will not BACKUP, or you know it is a protected original, tell us and we will arrange a flux read.

Two Things We Have Not Been Able to Test

The sector comparison was done in MAME, which emulates the drive exactly but not the Gotek. FlashFloppy, the usual Gotek firmware, writes back to .DSK images, and our blank is a plain 40 track single sided one, but we have not had a Gotek on the bench for this guide. If the first reader to try it finds the image comes back unchanged, or wants an HFE instead, we will add one. And the discs swap in step 4 assumes BACKUP 1.2 or later, which reads nothing from drive 0 until you press ENTER; every System Master we hold has it.

Why Bother If the Software Is Already on the Site

Because the software is the least of it. Two copies of the same game can hold different things in the sectors nobody sees: the previous owner’s letters, a working version of a program before it was finished, a listing somebody meant to erase. The article Help Us Preserve the Einstein’s Software and Find What Was Lost says why we ask, with examples.