Ask HN: 3.5 inch diskette read errors, would a period correct drive do better?
Posted by rietta 19 hours ago
My first attempt at restoring 1991 Learning Company Spellbound for DOS for my children is dubious. Despite being stored nowhere near magnetic sources, there are read errors on the 3.5 inch floppies and Linux could not mount them. ddrescue extracted data but I have not confirmed it works. The box also have 5.25 inch disks but I do not have a reader online at the moment, that is its own project.
My technical question is this, the USB 3.5 inch drive I have is a "USB Portable Diskette Drive" that was Made in China but has no obvious sponsoring branding. If I take the time to bring back to life a more period correct system with an actual IDE floppy drive would it read the disks more accurately?
My goal is to get more of this good DOS and early Windows educational software working for my children. This particular title is meaningful because I have the actual boxes and learned on it myself all those years ago.
One option for hardware is my parent's Leading Edge WinPro 486. The case looks to be in good shape but I have not opened the case to see the condition of the capacitors yet. It has a natively mounted 3.5 and 5.25 inch drive.
Comments
Comment by PaulHoule 18 hours ago
https://en.wikipedia.org/wiki/KryoFlux
which might let you get most of the bits from a bad block. See
https://goughlui.com/2013/04/21/project-kryoflux-part-1-the-...
Comment by rietta 18 hours ago
Before I spend well over $100 importing that device, I previously was thinking of brining up a 2001 era motherboard with a USB stack and can natively host the drives, but the 486 that has sat unused may be a solid option. I presumably can find a way to transfer data to a modern system over serial cable or something.
Comment by vunderba 17 hours ago
If your goal is to use it on a period-correct system, I’d go with 34/40pin adapters that lets you read flash cards, USB, etc.
A lot of my friends have kept their old 486 computers, and everything is period-correct except for the hard drive and floppy drive which have been replaced with a CF-to-IDE for the HDD and Gotek running FlashFloppy firmware for the 3.5".
Comment by VogonPoetry 10 hours ago
I've had quite a lot of success, almost 100%, over quite a long time - both 5.25 and 3.5. I did use older drives intended for "desktop" machines. The drives from Japanese companies seem to be the most reliable; NEC, TEAC. The 3.5 USB Portable diskette drives are based around laptop floppy designs. You won't be able to find a direct 5.25 to USB adapter (or modify one to work) as the speeds / data rates are all wrong, so you will need something like a GreaseWeasel or old PC for those.
I've used different reading mechanisms over the years; an old PC running Linux with a real floppy chipset + custom raw reading code, custom hardware with an F82077 + Atmel + SDCard, and most recently a GreaseWeasel.
The floppies I've recovered were stored relatively well, but were mostly my and family members data - not commercial floppies. If there is any copy protection on the floppies you are trying to read you may need to capture the flux transitions. For these, I'd check archive.org to see if someone has already generated a copy.
For 5.25 floppies fingerprints and surface blemishes can be softened / removed with ISO Propyl and a Q-tip. Floppies designed for cleaning the heads of drives seem to now be very expensive / non-existent. Manually cleaning the heads of a 3.5 drive is way more difficult. I've got ideas about using Face mask / filter material to create a cleaning tool, but it is on the experiments to try list.
Even back when floppies were a thing, I found that 3.5 drives were more un-reliable between machines than 5.25 drives. I think there was more variation in head alignment and track positioning. When I've had issues, I've always been lucky in that switching the drive vendor / model made reading the floppy possible even if it took multiple attempts or was very slow.
Good luck.
Comment by anenefan 18 hours ago
The thing I'd recommend is search of an image of the disks if they exist. Next best is an emulation eg [1] [2] which I found by way of google and yandex
[1] https://www.abandonwaredos.com/abandonware-game.php?abandonw... [2] https://archive.org/details/super-solvers-spellbound-dos-en-...
Comment by laruss5 18 hours ago