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Questions tagged [floppy-disk]

For questions related to the use, restoration and imaging of floppy disks.

7
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2answers
2k views

Repairing/Lubing/Fixing Amiga 500 floppy drive

I have acquired an Amiga 500 that seems fully functional, but the floppy disk drive seems to have mechanical issues. I could get it to read a few floppy disks until the last one wouldn't pop out when ...
3
votes
2answers
207 views

Is there a program I can run on the C64 to speed up booting of a game?

Though I had several friends back in the day with a Commodore 64, I only recently acquired one after a friend gave me his old one before he moved house. As such, I'm diving in to learning about the ...
18
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4answers
3k views

Wanted: 5.25 floppy to usb adapter

I have found inexpensive (~$15) 3.5in floppy to USB adapter cables but have been unable to find a similar adapter for 5.25 floppy drives. Does anybody make such a thing? Are the pinouts of a 3.5 the ...
7
votes
4answers
417 views

Drilling 720Kb floppies to 'upgrade' them to 1440Kb?

I remember back then, there were few people that used to drill an extra hole on them to double their capacity. Surprisingly, it worked! While the other way around is plausible I am quite unsure of ...
10
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2answers
698 views

Replacing the Floppy drives in my Amiga 3000

My Amiga 3000 is starting to show its age, and recently one of the two internall floppy disk drives appears to have given up the ghost... I'd like to replace the drive but the A3000 case doesn't have ...
9
votes
1answer
427 views

HxC floppy emulator on Amiga 1200, second virtual drive disappears after reboot

I've recently purchased a HxC/Lotharek SD Card floppy drive emulator. It's working well replacing DF0: but I'm seeing some odd behaviour with its emulation of DF1:. On the first boot after power-up, ...
4
votes
6answers
3k views

Were any external disk drives stacked vertically?

There was a time when floppy disk drives were big, expensive devices that in many cases, instead of being components of a computer, would be separate machines connected by a cable, in some cases with ...
21
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5answers
5k views

What makes a floppy disk bootable?

A lot of web sites describe how to create a bootable floppy disk using an existing image (via dd). But what about the image makes it bootable? I'm interested in making my own bootable floppy images ...
16
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4answers
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Why did 3.5" floppies win (and not another size)?

It's an open question whether desktops would've kept using 5.25" until the end of the floppy era, but laptops meant something smaller was going to be introduced; that much was essentially ...
12
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7answers
1k views

How to at least partially read damaged sectors of floppy disk?

It is necessary, that the floppy drive, just like CD-ROM, attempts achieving 100% data integrity using the help of error correction. If a sector is not readable, it just does not get sent to the ...
19
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6answers
6k views

Why was the shrinking from 8″ made only to 5.25″ and not smaller (4″ or less)?

Answers and comments to Why were 5.25" floppy drives cheaper than 8"? suggest some reasons why floppy disks moved from 8" to 5.25"; basically it seems the smaller size reduced engineering ...
23
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2answers
4k views

Why were 5.25“ floppy drives cheaper than 8”?

The first floppy disks were eight inches. This size was set by IBM; I haven't been able to find any indication of why they chose it, but maybe it was just because it seemed quite small to them ...
3
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3answers
198 views

Gotek drives for MS-DOS (plus few more constraints)

I have installed two gotek device instead of two old unworking floppy disk drives (in particular on an Olivetti PCS 86). And the result is something like this: (The one on the right should the the A:...
13
votes
4answers
5k views

Where can I find an external 8-inch floppy disk drive?

Where can I find an external 8-inch floppy disk drive? I have some data I would like to retrieve from a really old 8-inch (200 mm) floppy disk, but have no working computer than has a drive to read ...
18
votes
1answer
3k views

Did 5.25" floppies undergo a change in magnetic coating?

3.5" floppy disks, in the transition from 720K to 1.44M, changed the actual coating to a different compound that was magnetically 'stiffer'. This was necessary to support the higher density, but meant ...
23
votes
4answers
2k views

What were the differences in floppy disk formats between Amiga and IBM/PC compatible computers?

The capacity in Amiga Old File System format (OFS, OS version 1.x) was 840KB, with the Fast File System ("FFS" (!)) introduced for OS 2.x onwards able to store 880KB. The PC format stored 720KB on the ...
2
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3answers
203 views

What was the DOS FAT12 720k floppy raw disk format structure?

I am looking for detailed info on the low-level floppy disk structure of an MSDOS-compatible 720k Double Sided Double Density disk. Stuff like GAP/SYNC patterns, ID and CRC Field structure, standard ...
9
votes
4answers
653 views

Is my opened floppy disk useless now?

I was wondering if floppy disks are ruined if, say, a terror of a 3 year old rips them apart... I had important pictures on a floppy disk. I was doing some spring cleaning and came across it and ...
4
votes
3answers
1k views

Recovering old Commodore 5.25" floppy disks

I picked up a Commodore 64 with about 1,500 floppy disks. Many of them are de-magnetised and there is currently only one disk I can run (been through about 100, I can see the files of 2 or 3 disks, ...
11
votes
8answers
2k views

Why did common floppies never advance past 1.4 MB in size?

The chronology of some early floppy standards was: 80 kB, 160 kB, 360 kB, 720 kB, 1.2 MB, finally 1.44 MB. (There were less common sizes such as 250 kB, 800 kB, ...
2
votes
1answer
140 views

How to read old 3.5" Macintosh formatted floppies on a MacBookPro

I have connected a USB external floppy drive to my Macbook Pro (OSX El Capitan). I am unable to "view" the external drive, and hence unable to access the floppy content. I have inserted a floppy, ...
47
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20answers
12k views

Did personal computers ever support 8" floppies?

When I look at the following picture, it seems a bit awkward to me that personal computers ever supported 8" floppies (unless the size of your computer case was as big as a fridge !): Am I right or ...
18
votes
7answers
3k views

Why not constant linear velocity floppies?

The outer tracks of a disk are longer than the inner tracks, and could therefore potentially hold more data. Constant angular velocity puts the same number of bits on every track, which wastes much of ...
7
votes
4answers
588 views

Amiga floppy disks and GCR vs MFM

According to https://en.wikipedia.org/wiki/Group_coded_recording the Commodore 1541 disk drive used a particularly efficient GCR encoding scheme to cram 170K onto the same 5.25" disks that in an Apple ...
22
votes
2answers
1k views

Cleaning 5¼" floppy drives

Going to the store is treacherous for me. So I prefer doing stuff at home, including cleaning up 5¼" floppy disks with only home supplies. Unfortunately, I do not know how or which materials/chemicals ...
7
votes
1answer
862 views

Availability of 5.25" floppy emulators?

Emulators from Gotek or HxC support 3.5" floppies. However none seem to support 5.25" PC drives. Are there any alternatives out there?
39
votes
2answers
5k views

What is between the sectors of floppy disks?

I've found this page which has an informative description of how sectors were encoded on floppy disks: http://nerdlypleasures.blogspot.com.au/2015/11/ibm-pc-floppy-disks-deeper-look-at-disk.html Do ...
4
votes
2answers
321 views

Can a Harlequin ZX Spectrum clone be modifed to run CP/M?

The ZX Spectrum (and therefore the Harlequin) has its ROM from $0000 to $3FFF, while RAM further up to $5AFF is used for the screen (see Memory-Map). As CP/M expects RAM from $0000 upwards the two are ...
32
votes
3answers
4k views

What modification is required from a PC floppy for use in Amiga?

Around the end of the time of Amiga popularity, obtaining a replacement Amiga floppy drive was a nuisance, while PC drives were ubiquitous and cheap. One could install a PC drive in Amiga after ...
4
votes
2answers
133 views

Tools for creating disk images on Mac Plus

I got BMOW's floppy emulator and have been pulling a bunch of files from 30 year old floppies (which have a miraculously low rate of failure) onto my SD card. One of the things I wanted to copy was a ...
8
votes
4answers
2k views

Purpose of two disk drives on the Osborne 1

I recently discovered the Osborne 1 computer, and I noticed it had two floppy disc drives. What was the purpose of including two drives?
12
votes
1answer
364 views

What did Microsoft customize on Windows 95 installation floppy disks?

I have a Windows 95 Upgrade 3.5" DMF installation disk set where several disks were infected by the boot sector virus known as "Chance.A". I'm interested in restoring these to their original contents. ...
8
votes
4answers
1k views

Were external floppy drives for Atari ST and Amiga inter-compatible?

Were external floppy drives for Atari ST and Amiga inter-compatible? For example, Commodore 1541* had its own serial bus protocol. But what about the external 3.5" DD floppy disk drive on 23pins D-...
7
votes
6answers
3k views

Formatting a 720K floppy disk over USB fails with Windows 10

I've read many times that USB floppy drives will not format (or read/write) 720K disks. But then I read several posts online where people say they have done it. Even with Windows 10 (which is what I'...
5
votes
1answer
416 views

How to install System 7.5.5 on a Macintosh SE/30 using floppies?

I have a Macintosh SE/30 with a formatted Disk. I'd like to install the latest System 7 on it that will run. According to Wikipedia that should be 7.5.5. According to several sources Apple has made it ...
7
votes
3answers
1k views

Was there a special drive, that saved much more than 1.44MB on an HD floppy disk?

I think that I have once seen an Internet article, which stated, that special drives are capable of making many megabytes of data out of one ordinary MF-2HD floppy disk. But I am unable to find it ...
4
votes
2answers
415 views

How can I use ImageDisk (.IMD) images with VirtualBox, WinImage, etc.?

I've got ImageDisk installed on my old 486, and I've been ripping some disks for archival purposes (some 3.5", some 5.25"). It spits out .IMD files, which contain some amount of header and metadata, ...
3
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2answers
86 views

FDD data dropouts after changing disks

I'm building a FDD controller out of a $10 microcontroller. It's mostly working pretty well, and I can read both 720kB and 1440kB PC MFM disks (the only ones I have to test with). However... if I ...
11
votes
3answers
773 views

Finding byte boundaries in floppy disk MFM bitstreams

I'm building myself a floppy disk interface based on a microcontroller. I'm successfully reading the bitstream off the disk and (probably) decoding the MFM bitstream into actual bits, based on the ...
8
votes
1answer
363 views

Weak bits on floppy for copy protection

How did the vendors using copy protection create weak bits on the floppies? This always fascinated me as a kid. I ended up finding a weak bit emulator that would intercept the floppy disk interrupt ...
10
votes
2answers
171 views

Apple II: ProDOS partitions on floppy disks?

On the Apple II using ProDOS, was it possible to create partitions on a floppy disk? Would it be possible to have two or more partitions on a 140k 5.25" or 800k 3.5" disk? (The question here is not ...
4
votes
1answer
208 views

Which DOS for a TRS-80 Model 4P?

Looking at the TRS-80 Disk Software Page, there's a rather extensive selection of DOS options that seem to work with the 4P and also claim high compatibility with the Tandy "TRSDOS" option. ...
33
votes
8answers
9k views

Why were floppy disks invented after hard disks?

For those of us who grew up with personal computers in the 1970's or 1980's, the experience was a very gradual migration from floppy disks to hard disks as the primary persistent storage. So, based on ...
5
votes
1answer
673 views

Copying disk images to Commodore 64 floppy disks

For some time now I have been on a mission to get back into playing games on a Commodore 64. I have bought an original Commodore 64C. I got hold of a original 1541 disk drive. I also got hold of a ...
3
votes
1answer
221 views

Using floppy disk interface on Future Domain TMC-1680 SCSI ISA card

I have this old card, a Future Domain TMC-1680 ISA SCSI card that has a 34-pin floppy disk connector on it. I am trying to research that to see if I can make it work (before anyone asks - just for the ...
11
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3answers
2k views

Only “Drive A:” detected with two floppy disk drives

I am trying to repurpose an old Acer Aspire M1641 to copy/format bulks of 3.5'' floppy disks. I think it's one of the last generations of computers to have a 34 pin floppy disk drive header as it also ...
24
votes
2answers
2k views

How did MS-DOS assign drive letters in the case of more than two floppy disk drives?

The IBM PC BIOS had provisions for up to four floppy disk drives, by virtue of returning the number of floppy disk drives in a two-bit field plus a none/some flag (allowing for reporting values of 0, ...
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vote
2answers
604 views

Commodore Amiga 600 Software Failure. “Error: 8000 0004 Task: 000026D0”

Software Failure on Commodore Amiga 600 when I insert a floppy in drive. Software Failure. Press left mouse button to continue. Error: 8000 0004 Task: 000026D0 Independent from the floppy I ...
10
votes
2answers
573 views

Bootable floppies lock up with floppy drive connected via USB adapter

I am currently trying to mount a 3.5'' floppy disk drive in a modern computer. What I did is that I bought a 34-pin floppy drive connector to external USB adapter so that I can connect it to my ...
8
votes
3answers
982 views

How to spin up 1541 drive without C64

I have a 1541 drive and I want to make it spin but I don’t have a Commodore computer. I don’t need to read data, I would just like the drive to spin. Can I manually tell it to spin using a raspberry ...