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94

This calls for a lengthy Floppies 101. For one, don't look at a floppy as something with an inherently byte orientated structure. There is none. It's like a magnetic tape (looped at the end). All orientation on this track is timing based. There are no cell markers or position markers or whatsoever. Well, there's a single marker that shows up once per ...


93

The term "Disk Operating System", or commonly "DOS", was used in the early days of personal computing to distinguish operating systems that also contained software for supporting disk devices, since not all of them did. The DOS software could access blocks stored on disk, that were organized into files, and there was "filesystem" software included for ...


65

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


63

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 mainframes.) In slightly more recent times (even thirty-odd years ago, and then as long as floppies were still useful), we used archiving tools with support for ...


62

It doesn't imply that it's the disk operating system so much as it implies that it's the disk-operating system. You could boot an Apple II from ROM, enter and run BASIC programs, load programs from cassette, and basically do whatever an Apple II can do, but there was no way to access files on disk. Apple DOS didn't really do any of the features of a modern "...


61

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 heads touching the media would end up with catastrophic effects. Floppies and tape drives are different. The heads are constantly touching the media directly ...


59

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 about a personal computer, then many minis may fit, and they did often offer 8" floppies like the RX01/02 type DEC had. If it's about (early) microprocessor based ...


45

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 especially useful (it either displays a message saying to insert a system disk, or they execute INT 18h - which runs BASIC if it's installed in ROM, or displays ...


44

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 go from a hard disk of this sort to floppy disks required a number of developments: in particular the ability to remove the platters (which came in 1962 with ...


40

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 separator circuitry (due to higher bandwidth needed), probably better shielding on the r/w head wiring and drive-to-controller cabling -> cost, development effort ...


39

The term DOS pre-dates the personal computer by a looong way: the term DOS/360 was first coined by IBM in 1964 as a new operating system for their System/360 mainframe computers, to replace TOS (tape operating system). IBM commissioned Microsoft (at that time a garage outfit) to write PC-DOS to run on their Personal Computer, which was launched in 1981. ...


37

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 is used for disk change on the PC, disk ready on the Amiga pin 2 on the connector is used for high-density detection on the PC, disk change on the Amiga So ...


37

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 electronics so that it knows where the sectors are. On a full format, a completely blank disk has these markers written. This takes time as the drive must apply ...


36

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 drums. Drums were huge cylinders with a magnetic surface, and a separate head for each track - something that would have been rather impossible with a disk. ...


35

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 world's first 5¼ inch floppy drive, the Shugart SA 400 minifloppy: Massaro: [Dr. An Wang of Wang Laboratories] said..."I want to come out with a much ...


34

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 Blu-ray. The fastest rotational speed for a floppy disk was 1440 rpm and the equipment would also write to both sides of the disk at the same time. This meant ...


32

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 to a smaller disk, there's less metal required for the drive's chassis, etc. The 8-inch drives also used a 50-pin data connector, whereas the 5 1/4-inch drives ...


30

The main thing is that there is no such thing as a "quick format" - That term is entirely misleading terminology invented by Microsoft. Quick Format doesn't "format" anything. What MS calls a "Quick format" is rather a "wipe directory" - It marks all sectors as unused and rewrites only the FAT and root directory. That process visits only a very limited ...


30

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 problem that reared its head with great regularity was that a full map file, required so that we could find the address of a function and set a debug break point in ...


30

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 different zones with 15 to 21 sectors per track. As a result some 120 additional sectors per side (or 100KiB per disk) could be used. To keep the data rate ...


28

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 machine. There may be files that are the same (DISK.ID or something). Just overwrite them. Then, invoke the INSTALL application from the copied directory. I think ...


28

The main technical parameter for a floppy disk's coating is its coercivity, i.e. the resistance of ferromagnetic matter to withstand demagnetization. Coercivity is measured in Oersted, after Hans Christian Ørsted, a Danish physicist who discovered the magnetic impact of electrical current. 5¼" disks storing 360K and 720K (SD and DD) used a coating with a ...


27

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-sync bytes are FF, followed by two "invisible" zeroes: byte 0 ** byte 1 ** byte 2 ** 11111111 00 11111111 00 11111111 00 The Apple II will read bits ...


27

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 cable swaps signals for grounds, grounding all signals. Since all the signals on a floppy disk are considered to be asserted when a zero (a logic 1 = ground) ...


27

As well as splitting across multiple floppy disks, there were several cabled communication options available ranging from your basic serial cables and sending data over via X/Y/ZMODEM or Kermit, but there was also specialized parallel cables (like printer cables) that could be used that facilitated even faster transfers. I think "LapLink" was a such a ...


27

The shutter spring in a 3.5” floppy forces the shutter back in its “closed” position when it’s opened. Losing it won’t have much impact on its day-to-day use, as long as there was no other damage to the shutter: when you insert the disk into a drive, the shutter is pulled open (which will be easier, without the spring), and when you eject the disk, the ...


26

Remember that these systems (not only the Osborne 1) didn't have harddisks. Everything ran from floppies. So usually you had one floppy where the program was on, together with OS related files. And another floppy for your data, texts and so on. That was workable with two drives, but still was impractical if you wanted to copy data. Usually there was some ...


25

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-living we can practically manufacture. Typical streamer tapes are often guaranteed for 30 years. Of course, under very strict handling and storage conditions - but ...


25

The simplest method of archiving old C-64 disks would be to get a ZoomFloppy and a 1571 floppy drive from eBay. I say 1571 because it's much less likely to have alignment problems. The ZoomFloppy will allow you to control the 1571 from a Windows, Linux or MacOS computer. You can convert the disks into .d64 images that are suitable for use with an emulator ...


25

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 files we used 1/2" mag tape: You've seen drives like this in older movies: These tapes could hold one hell of a lot of data: Maybe 50Mb. (Really high ...


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