8″ Floppy On Your PC?

We should probably have a new metric for measuring mass storage performance: bytes per pound. An old IBM tape drive from the S/360 days, for example, could hold almost 6 megabytes of data. It also weighed more than a typical refrigerator. Today, a tiny postage-stamp-sized card can hold gigabytes of data and weighs — at most — a few ounces. Somewhere in the middle is the old 8 inch floppy drive. At its peak, you could cram about 1.2 megabytes on it, but even with the drive you could lift it all in one hand. These disks and their descendants ruled the computing world for a while. [Adrian asks the question: can you use an 8″ floppy drive on a PC? The answer is in the video below.

He didn’t do it on a lark. [Adrian] is getting ready to restore a TRS-80 Model II so he wanted to create some 8″test floppies. But how do you marry a 40-something-year-old drive to a modern computer? He had a few drives of unknown condition so there was nothing to do but try to get them working.

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Arduino Nano Floppy Emulator For When Your Disk Is Not Accessible

Among the plethora of obsolete removable media there are some which are lamented, but it can be difficult to find those who regret the passing of the floppy disk. These flexible magnetic disks in hard plastic covers were a staple of computing until some time in the early 2000s, and their drives could be found by the crateload in any spares box. But what about today, when there’s a need for a real floppy drive and none is to be found? Enter [Acemi Elektronikci], with an Arduino Nano based floppy emulator, that plugs into the floppy port of a PC old enough to have one, and allows the easy use of virtual floppy disks.

Aside from the Nano it has an SD card and associated level shifter, and an SSD1306 i2c screen. Most of the Arduino’s lines drive the floppy interface, so the five-button control comes to a single ADC pin via a resistor ladder. He freely admits that it’s not a perfect cycle-exact emulator of original hardware and there may be machines or even operating systems that complain when faced with it, but for all that it is a useful tool. One of the machines that may have issues is the Amiga, but fortunately there’s a fix for that with a Raspberry Pi.

The Ultimate 1541 Talk by Michael Steil, presented at the Vintage Computer Festival West

The Ultimate Commodore 1541 Drive Talk: A Deep Dive Into Disks, Controllers, And Much More

When we think of retrocomputing, it’s very often the computers themselves that get all the glory.  There’s nothing wrong with this of course- the computers of the late 70’s and 80’s were incredible machines that were chock full of hacks in their own right. But some of the most interesting hacks of the day happened not in the computers, but rather in their peripherals. A devotee of such periphery is [Michael Steil], who was driven to compile years of research, knowledge, and hard data into The Ultimate Commodore 1541 Drive Talk which you can view below the break.

In the talk, [Michael] covers the physical disk composition and construction, the disk drives, controller hardware, and the evolution thereof. The bit-by-bit breakdown of the tracks, sectors, and header information on the disks themselves is fascinating, as is the discussion of various copy protection techniques used by vendors to prevent piracy at a time when sneakernet was in full swing.

The descent into the circuitry of the controller reveals a venerable 6502 CPU which powered many vintage computers. Further discussion divulges the secrets for getting higher performance from the 1541 drive using innovations that are as recent as 2013.

A computer historian and archaeologist, [Michael] discusses how using modified vintage hardware is sometimes enough to save your old floppy collection. He also shows how modern interfaces that read disks all the way down to the magnetic flux level can be used to reconstruct missing data.

[Michael] masterfully lays bare the complexity, engineering, and hackery that went into storing less than 200kb of data. Whether you’re a Commodore enthusiast or not, your appreciation for the 32GB USB stick collecting dust on your desk is bound to grow!

We’ve covered [Michael]’s exploits before, and you may wish to check out the Ultimate Apollo Guidance Computer Talk or the Ultimate Gameboy Talk. Do you have your own favorite retrocomputer hacks and insights to share? Be sure to let us know via the Tip Line!

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Raspberry Pi Floppy Driver Uncovers Fishy Secrets

A forum post by New Zealand electronics enthusiast [zl2wrw] about retreiving waypoints from a mysterious floppy disk caught our eye. The navigation system on his friend’s fishing boat had died and was replaced. But the old waypoints were stored on a 3-1/2 inch floppy disk that was unreadable on a normal PC. Not to be deterred, [zl2wrw] then looked for another solution — apparently a list of hot NZ fishing spots is worth quite the effort.

The tool he discovered, and the main point of this story, is the bbc-fdc by [Jasper Renow-Clarke] aka [picosonic]. [Jasper] made this project to read 5-1/4 inch Acorn DFS floppies from his BBC Micro. But bbc-fdc can be used to read a variety of floppy disk formats, such as DOS, C64, Apple II, and others It can also just capture raw magnetic flux transitions on the disk, blissfully unaware of any logical structure to the data. We recently wrote about another Raspberry Pi Floppy Drive Controller project by [Scott Baker]. What sets [picosonic]’s project apart is that he’s not using an FDC controller chip here. The only interface electronics is a couple of open-collector 7406 ICs. Data is read using the SPI peripheral. If you need to archive old floppy disks or do a forensic analysis of unknown disks like [zl2wrw], then one of these two projects will almost certainly do the trick.

Meanwhile back in New Zealand, [zl2wrw] discovered that the floppy format was standard (Modified Frequency Modulation, MFM) by examining the raw flux dump. However, the filesystem was a mystery — it didn’t quite match any of the usual suspects. So [zl2wrw] dug into the hex dump of the data and figured out enough of the structure to manually recover the waypoints. Subsequently, a user on the forum found a document describing the file system used by Furuno GPS units, which proved to be a close match albeit after the fact. Alas, [zl2wrw] hasn’t publish the coordinates of those good fishing spots.

Have you had any successes (or failures) when it comes to reading data from old disks? Or have you encountered peculiar disk formats and/or file systems, where having a tool like this could have been helpful? Let us know in the comments below.

Running Modern Linux From A Single Floppy Disk

There was a time when booting Linux from a floppy disk was the norm, but of course, those days are long gone. Even if you still had a working 3.5 inch drive, surely the size of the modern kernel alone would far exceed the 1.44 MB capacity of the disks, to say nothing of all the support software required to create a usable operating system. Well that’s what we thought, anyway.

But then [Krzysztof Krystian Jankowski] dropped Floppinux, a live Linux OS that boots from just a single floppy. There’s even a few hundred KB left over on the disk, allowing the user to tuck a few of their own programs and scripts onboard before booting it up. But most impressively, the project doesn’t rely on ancient software releases like so many other embedded systems do. Every component of Floppinux is pulled directly from the cutting edge, including version 5.13.0-rc2 of the Linux kernel which is literally just a few days old.

Floppinux running on the Asus Eee PC

Of course some concessions had to made in order cram the latest Linux kernel and build of BusyBox into slightly north of 1 MB, so Floppinux certainly isn’t what anyone would call a daily driver. The kernel is stripped down the absolute minimum, and is targeted for the decidedly poky i486. [Krzysztof] had to be very selective about which programs actually made the cut as well, so once the system is booted, there’s not a whole lot you can do with it outside of writing some shell scripts. But then, that was sort of the goal to begin with.

If you’re wondering how [Krzysztof] pulled it off, you don’t have to. He walks you though the entire process, down to the commands he used to do everything from pull down and compile the source code to creating the final disk image. Even if you don’t own a floppy drive, it’s well worth following his guide and booting the image up in QEMU just to say you’ve officially built a Linux system from scratch. It’s good for more than just bragging rights; learning how all the components of a minimal install like this fits together will no doubt come in handy the next time you find yourself poking around inside an embedded Linux device.

Reading Floppies With An Oscilloscope

There’s a lot of data on magnetic media that will soon be lost forever, as floppies weren’t really made to sit in attics and basements for decades and still work. [Chris Evans] and [Phil Pemberton] needed to read some disks that reportedly contained source code for several BBC Micro games, including Repton 3. They turned to Greaseweazle, an interface board that can dump just about any kind of floppy disk if it is attached to the right drive. The problem is that Greaseweazle couldn’t read the disks due to CRC errors. Time to break out the oscilloscope and read the disk manually, which is what they did.

Greaseweazle provides a nice display of read sectors and shows timing coming from the floppy read head. The disk in question looked good with reasonably clean timing clocks except in the area of one sector. At that point, the clocks degenerated into noise. Looking on the disk, it was easy to see why. The actual media had a small dent in it.

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An Arduino With A Floppy Drive

For many of us the passing of the floppy disk is unlamented, but there remains a corps of experimenters for whom the classic removable storage format still holds some fascination. The interface for a floppy drive might have required some complexity back in the days of 8-bit microcomputers, but even for today’s less accomplished microcontrollers it’s a surprisingly straightforward hardware prospect. [David Hansel] shows us this in style, with a floppy interface, software library, and even a rudimentary DOS, for the humble Arduino Uno.

The library provides functions to allow low level work with floppy disks, to read them sector by sector. In addition it incorporates the FatFS library for MS-DOS FAT file-level access, and finally the ArduDOS environment which allows browsing of files on a floppy. The pictures show a 3.5″ drive, but it also supports 5.25″ units and both DD and HD drives. We can see that it will be extremely useful to anyone working with retrocomputer software who is trying to retrieve old disks, and we look forward to seeing it incorporated in some retrocomputer projects.

Of course, Arduino owners needn’t have all the fun when it comes to floppy disks, the Raspberry Pi gets a look-in too.