Questions tagged [floppy-disk]

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

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35
votes
3answers
11k 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 ...
55
votes
9answers
20k views

How long will floppy disks maintain data integrity?

This was on CNN today: The U.S. is still using floppy disks to run its nuclear program Which led me to read through this article: Think the floppy disk is dead? Think again! Here’s why it still ...
15
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3answers
2k 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 ...
41
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3answers
7k 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 ...
29
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2answers
4k 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, ...
35
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8answers
10k 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 ...
16
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5answers
4k views

Adding the third floppy drive?

I've seen a few computers with more than two floppy drives, most with two 3.5" and one 5.25". My question is how was this achieved? I've heard that it could be done with a second controller card, but ...
12
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4answers
3k views

Writting DSK images onto a 3″ floppy for Amstrad/Sinclair computers

For a project I'm working on, I need to write some disks to test on my Amstrad CPC 6128. I've got some 3″ blank disks, and all my Amstrad computers (CPC and PCW) have 3″ disks, as well as my Spectrum +...
11
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3answers
2k 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 ...
28
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3answers
5k views

Magnetic exposure to floppy disk damages file system and requires complete reformat?

What I noticed is, that formatting a floppy disk takes three times as much time for the same data amount as writing a file to the disk normally. The accoustically perceivable jumps of the head between ...
16
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4answers
5k views

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 ...
3
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1answer
180 views

Converting Apple II ProDOS blocks to DOS tracks and sectors

The 8-bit Apple II had two disk operating systems with different disk access semantics. DOS used tracks and sectors. A sector is 256 bytes. ProDOS used blocks. A block is 512 bytes. But mapping ...
50
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9answers
20k views

Why were floppy drives not any faster?

180rpm to 360 rpm, unlike 12000rpm on optical discs, was how fast floppy disks got. I am not sure, whether all drives had the same speed, but 360rpm is not close to the physical stress limitations of ...
50
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20answers
14k 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 ...
24
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5answers
7k 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 ...
37
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8answers
8k views

How long can a floppy disk spin for before wearing out?

I'm mainly interested in 3.5" floppies here, as they're what I have lying around, but other sizes could also be interesting to hear about if anyone has the data. As I understand it, the head rubs ...
31
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6answers
13k views

Can I image Amiga floppy disks on a modern computer?

Is there any way of reading Amiga floppy disks to a PC hard drive? Can I use a standard floppy drive with a firmware program that will translate it? Do I need an external drive or a working Amiga ...
26
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3answers
4k views

When did 5.25″ floppies exceed the capacity of 8″?

When 5.25″ floppies were introduced, in the mid-to-late seventies, they would have had less capacity than the older 8″ because, well, less area on which to store data. On the other hand, being cheaper ...
23
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8answers
5k 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 ...
31
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5answers
4k 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 ...
27
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9answers
7k views

What other tricks were there to get more data onto floppy disks?

I remember using a utility back in MS-DOS 3.3 days, called MAXI Disk, that somehow magically managed to get 420K on a 360K 5¼″ disk. I assume it managed it by destroying some redundancy like a backup ...
-1
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2answers
999 views

How long can a HD floppy disk hold 2.88MB before erasing itself?

From Wikipedia - Floppy_disk: to format or write to this high-coercivity media, the high-density drive switched its heads into a mode using a stronger magnetic field. When these stronger fields ...
30
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4answers
2k views

Absolute maximum number of nibbles on an Apple II floppy disk track?

The Apple 2's disk drive controller and 5¼" floppy disks have the following metrics: The disks is spun at (roughly) 300 RPM (Revolutions per Minute), which means it takes = 1000 ms/sec / (300 RPM / ...
24
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4answers
3k 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 ...
21
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2answers
4k views

Is there a better way to the 6 disks install of Windows 3.1

I want to install Windows 3.1 on my MS-DOS 6.22 Machine. I have the 6 disk images. But I only have 1 or 2 spare Floppy disk that I can write the disk images onto. One way I can think of is to write ...
13
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4answers
8k views

Installing Windows 95 by floppy?

Ok so I have an old laptop with only a floppy drive. It came with windows 95 on it but suffered from some terrible BSODs that I could not resolve. I figured I would just download some windows 95 ...
27
votes
2answers
5k 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 ...
19
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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 ...
14
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8answers
4k 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, ...
13
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3answers
3k views

Writing 800k Mac floppy images for 1.44M-equipped Macs using Linux

If you have Macintosh filesystem image of an 800k boot disk, but your physical Mac has a 1.44M SuperDrive, how can you produce a physical disk that can boot that Mac?
7
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1answer
2k 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
2answers
724 views

How could a 16-sector PROM Apple II access a 13-sector disk?

When the Disk ][ first came out for the Apple II, the PROMs on the interface card only knew how to work with a 13-sector format. Around 1980, the Disk ][ was updated with 16-sector PROMs either for ...
6
votes
2answers
301 views

Why does _Beneath Apple DOS_ show FM encoding rather than GCR?

From the beginning in 1978 the Apple II floppy disk system used GCR encoding to convert data bytes to sequences of binary values to be written to the diskette: first 4-and-4 encoding (never released), ...
4
votes
2answers
295 views

Why does Amiga 500 reset when reading a faulty disk

I have a copy of Syndicate disks for Amiga (I have original as well) and apparently the disk is damaged / faulty. It loads up to language selection menu, then tries to read disk and resets the ...
3
votes
2answers
693 views

What file formats were used for binary executable files on later Sinclair ZX Spectrums?

The last official version of the Sinclair ZX Spectrum was the +3, released after the company was owned by Amstrad. It included a 3-inch floppy disk drive as used on other Amstrad computers. But even ...
13
votes
4answers
4k views

Is there any way today to recover/dump 2M disks?

2M disks where formatted using 2MGUI to increase 3"1/2 & 5"1/4 DD/HD/ED disks' capacity. Is there any way today to recover/dump these disks to a file with modern hardware? Specially the 5"1/4 ...
9
votes
2answers
256 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 ...
9
votes
1answer
630 views

How can I tell if an Apple II disk image is bootable?

I have around 500 floppy disk images from an Apple II and IIgs BBS/usergroup that closed down recently. Some of the disks are bootable, but many aren't. Is there an easy way to tell if a disk boots ...
6
votes
1answer
986 views

DD vs HD vs ED floppy disks: lifespan/writecycle difference? Other differences?

DD, HD and ED floppy disks have individual materials to match their densities. But is density their only difference? Are there any differences regarding: Maximum allowable rotation speed? Rewrite ...
5
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3answers
1k views

Is there anything useful for a retro in these cheap Chinese floppy drives?

Looking on eBay for floppy drives, I came across these incredibly cheap Chinese 3.5" USB drives (there are lots of them on offer). https://www.ebay.com/itm/USB-1-1-2-0-Portable-External-3-5-1-44MB-...
5
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4answers
1k views

How does the Spectrum +3 know whether a disk is bootable or not?

I've been looking through documentation on The Sinclair/Amstrad Spectrum +3 which was the only Spectrum that came with a built-in floppy disk drive. The disk format was based on The Amstrad CPC and ...
1
vote
2answers
215 views

How do I know where the file directory is stored on a Spectrum +3 disk layout?

I'm trying to parse Spectrum +3 disk images. I only ever had a tape-based Speccy back in the day. The +3 had a built-in floppy drive but was late to the party and not that successful. It had the same ...
1
vote
2answers
206 views

Is it possible to read floppy disks at non-standard rotation speeds (RPM)?

According to this article 3.5-inch floppies rotate 300-600 times per minute (RPM). It is possible to overclock the RPM and will that result in higher transfer speeds? Or is it possible to read a disk ...