104
votes
What is between the sectors of floppy disks?
This calls for a lengthy Floppies 101.
For one, never assume a floppy as something with an inherently byte orientated structure. There is none. Just magnetic reversing areas. It's more like a magnetic ...
- 213k
72
votes
Accepted
What is the "two-drive trick" that can read Amiga disks on a PC?
This only works with 2 drives on the same controller and cable. The floppy controller doesn't know when the disk (hardware) has been switched on the port (software), so a transfer command can be ...
- 939
70
votes
Dealing with oversized files decades ago? Data transfer in the age of floppy disks
Forty years ago, a 7MB file would be unheard of, at least in contexts where floppies would be the only available means of transferring it. (Tapes were commonly used for large transfers on minis and ...
- 118k
68
votes
Did personal computers ever support 8" floppies?
The Radio Shack Model II had a built-in singled-sided Shugart 500k 8" floppy drive.
https://en.wikipedia.org/wiki/TRS-80_Model_II
- 1,206
64
votes
Accepted
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
As so often it depends on your definition of 'personal computer'
If it's ...
- 213k
63
votes
Why were floppy drives not any faster?
That answer is somewhat trivial:
Hard disks and optical drives are contact-less technologies - Nothing touches (or is even allowed to touch) the media while it spins. On a hard disk or CD-ROM, the ...
- 33k
63
votes
How long can a floppy disk spin for before wearing out?
Anecdotal evidence (*1)
We had a bank as customer with branch offices all over the state. These were the 70s, the final years of batch only, although, already using remote batch with local data ...
- 213k
50
votes
Accepted
What makes a floppy disk bootable?
The notion of a bootable-vs-non-bootable floppy is a little odd. It's worth noting that almost all floppies you're likely to have are actually bootable: it's just that they boot a program that isn't ...
- 12.8k
50
votes
Why were floppy disks invented after hard disks?
Floppy disks are harder to get right than hard disks. Early hard disks were enormous; the IBM 350 used fifty 24-inch platters. They were also rather fragile and cumbersome (heavy and power-hungry). To ...
- 118k
43
votes
Accepted
Why were floppy drives not any faster?
As you mentioned, speed was considered sufficient for the typical applications at the time they were introduced. Also, any significant rotational speed increase would have meant:
More complex data ...
- 5,660
41
votes
Accepted
Why did connecting the IBM PC 3.5" FDD backwards cause the problems it did?
One side of the cable is normally all ground. The other is all signals. This was done so a ribbon cable would have a ground wire between each signal wire, which helps prevent crosstalk.
Flipping the ...
- 801
41
votes
Accepted
What are the three or four holes on the back of a 3.5inch floppy disk indicating and used for?
The upper two (or one) notches at the sides, are to grab and clamp the disk against ejection - an addition Sony made to the 3.5 design on request by Apple, which had that already patented for the ...
- 213k
40
votes
Accepted
Why were floppy disks invented after hard disks?
While Stephen Kitt's answer already hits the core, I believe it needs a bit more history, as direct access magnetic storage did start quite a while before the IBM 350.
Drums and Disks
First there were ...
- 213k
40
votes
Accepted
What is the (standardized) weight of a 3.5 inch floppy disk?
The short answer / TLDR: One 3.5-inch floppy disk weighs between 15 - 25 grams. The average (mean) weight of one 3.5-inch floppy disk is 18 grams, the median is 17 gram. Of that weight 75% is ...
- 1,662
39
votes
Accepted
What modification is required from a PC floppy for use in Amiga?
The differences between PC floppy drives and Amiga floppy drives are as follows:
PC floppy drives normally answer to drive select 1 (DS1), internal Amiga drives answer to DS0
pin 34 on the connector ...
- 118k
39
votes
Accepted
Magnetic exposure to floppy disk damages file system and requires complete reformat?
A formatted disk contains markers which identify the start of each track and the start of each sector within the track. These markers are fixed magnetic sequences that are picked up by the drive ...
- 8,031
39
votes
Why were floppy drives not any faster?
I used to work for a company called ‘Rimage’ who manufactured robotic duplicators for floppy disks, the company still exists and today manufactures robotic equipment to publish/duplicate cd, dvd and ...
- 391
39
votes
Accepted
When did 5.25″ floppies exceed the capacity of 8″?
In practice, 5.25" drives equalled or exceeded the capacity of 8"
drives when 5.25" floppy drives started using HD media.
The Evolution of 5.25" Drive Systems
There are only two ...
- 24.6k
37
votes
Why was the shrinking from 8″ made only to 5.25″ and not smaller (4″ or less)?
A 2005 interview with Don Massaro, vice-president of
engineering and manufacturing, and George Sollman, product manager, both of Shugart Associates, lists the design constraints that resulted in the ...
- 17.4k
37
votes
Twist in floppy disk cable - hack or intended design?
This was a good piece of production engineering.
IBM expected to sell lots of twin-floppy PCs, even after the launch of the XT (personal experience in a UK reseller in late 1984).
To assemble a twin-...
- 1,162
36
votes
How long can a floppy disk spin for before wearing out?
I did some assembly development on a dual-floppy (5 1/4" double-sided) IBM PC 5150 in 1982/83 (PC DOS 1.1 and onward). Boy, did that exercise the floppy drives! We wore out floppies all the ...
- 579
34
votes
How long will floppy disks maintain data integrity?
Can you take these disks off the shelf 30 years later and still expect to read their data?
Yes.
Although we all experienced floppies fragility, the magnetic media in fact is one of the longest-...
- 469
34
votes
Accepted
Why are the magnetic floppy disk drives (FDD) heads not frictionless?
TL;DR:
"Frictionless" Floppies are called Hard Disks (*1), consisting of a hard media platter and a head in distance of the media (flying or otherwise)
Floppies are 2D tapes. While slower ...
- 213k
33
votes
Accepted
Is there a better way to the 6 disks install of Windows 3.1
If my memory serves well, Windows can be installed from a directory on hard disk. You need a means of reading all disks and storing its files on the same directory on the hard disk of your target ...
- 18.6k
33
votes
Accepted
Why were 5.25″ floppy drives cheaper than 8″?
A few miscellaneous thoughts:
Less Materials: On a certain level, a smaller device is cheaper, simply because it uses less raw materials. You need less of the magnetic coating if you're applying it ...
- 8,036
32
votes
Accepted
How does "bit-slip" copy protection work?
The Apple II reads disk tracks as a continuous stream of bits. To make sense of the data, it's necessary to figure out where individual bytes start. This is done with self-sync bytes.
Standard self-...
- 8,775
32
votes
Did personal computers ever support 8" floppies?
Back in the day I used to use an Intel MDS-80 which had an 8 inch floppy beside the screen.
We often had a pair of expansion drives (also 8") in an expansion unit below the main system box.
One ...
- 489
32
votes
Why not constant linear velocity floppies?
But as the linked article indicates, while this is used on optical disks, it has generally not been used on floppy disks.
It has. Apple's famous Twiggy drive was one attempt to do so. It featured 6 ...
- 213k
32
votes
How long can a floppy disk spin for before wearing out?
My 1980 edition of the Apple II DOS manual mentions that, for a 5.25" disk:
With reasonable care a diskette will give you an average life of 40 hours——which is a lot, when you consider the few ...
- 421
31
votes
Dealing with oversized files decades ago? Data transfer in the age of floppy disks
40 years ago - 1978 - there was no home/hobbyist/small office computing to speak of. Maybe a few hundred people altogether. So you must be talking about commercial/industrial computing.
For large ...
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Only top scored, non community-wiki answers of a minimum length are eligible