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23

To my understanding Taiwanese CMC still produces 3.5 inch diskettes in PRC. By now they seem to be the last major supplier. They became the biggest supplier of diskettes already in the 1990s, doing production for most brands from Maxwell to Verbatim, later they also acquired many (former) famous brand names (including Verbatim). They did (and still do) the ...


1

Sectors are nothing new Computers had them with magnetic tape. A "sector header" was a quasi-unique pattern that shouldn't occur anywhere else in data.* So the drive simply waited until a sector header appeared, then read the sector in the normal manner. The sector header included the sector number. If it wasn't the sector desired, then go back to ...


1

TR-DOS programs are usually started as BASIC ones, by loading *.B file a number of bytes given in the file descriptor. No sector size is honored this time and loading address is essentially ignored (but set to be equal to byte size most of times). After the basic program is run, the things might go mad in any possible way. The most simple programs would do ...


4

How it [likely] works When ZX-Spectrum with Beta interface (re)starts, Beta Disk Interface sets ROM_CS flag to disable its builtin ROM and connects TR-DOS ROM to initialize the interface, dirves, and to try to boot from floppy. This behavior can be different from one computer to another, for example, in my personal 48K Speccy with Beta-128 interface it ...


32

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 than tapes, their advantage is in (faster) random access for small data sets. The construction was made to save on tapes. They were never intended for continuous ...


11

The head gap must be very narrow to be able to make sharp magnetic transitions on the moving magnetic media. It also means the magnetic field does not bulge out too much out from the head so the media must move very near the head. If the gap was larger, it would bulge out more, but be weaker and it could not make sharp transitions on the media, which means ...


2

How do both applications know the start of the first sector and the end of a the last sector of a floppy disk, in order to accurately visualize it on an image (FDM) ... Having a look at the screen shot from the website of the manufacturer, I doubt that this is an accurate visualization of the floppy: A real floppy disk track begins with some empty space, ...


9

What information could be extracted from visualized magnetic information? The very same as with a magnetic head: flux changes - and from there everything else, like headers, sectors and the data within. Could below visualization be decoded into data? It can be decoded into a bitstream, as it seems to hold one. But I doubt that the shown section is long ...


4

TL;DR: For the titular question: A floppy drive doesn't identify anything at all (some may to track 0). For tracks it steps in or out as much as the controller tells. It also doesn't identify sectors but read the raw magnetic stream. it is the controller that looks for data blocks, picks headers thereof and acts according to whatever address is written there....


23

The track identification part is quite simple. Floppy formats are standardized so that there are specifications what is the distance between tracks (e.g. 96 tracks per inch) and what is the position of the tracks from some reference point, so the drive is designed accordingly so that moving the head one step will always step one track, and the heads are ...


8

Where there are various formatting schemes for floppy disks, the usual is to break down a track into sectors. This is done during formatting and the individual sectors are written with empty data in them along with "buffer" zones between them. Each of the sectors typically has an "address" that in incorporates the SIDE, TRACK, and SECTOR ...


2

Take the drive mechanism out of a baby/classic Mac & install it in your Apple 3.5 Drive enclosure. Not sure if this would work for UniDisk 3.5 drives. Just remember when moving or shipping these drives, ALWAYS either insert the yellow plastic shipping disk or leave a genuine 3.5 floppy disk in the drive. Failure to do so means the heads are going to ...


1

On BK-0010/11/11M one would use an utility like Topor4 (Axe4) to split the file:


4

How to determine the required RPM for a 3.5-inch floppy disk as disks can apparently require different speeds? Now, or back then? In general, drive speeds are rather fixed with disk type and system. Speed for most systems is 300 or 360 RPM, except a few outliers and variable speed drives. How does a floppy drive know what RPM speed to use and if it is ...


2

TL;DR: No. Simply cranking up the RPM will at best only reduce capacity of a floppy. Floppy systems are a balanced combination of Host System,, Controller Electronics, Drive Electronics, Drive Head and Floppy Material, all selected to work at a concerted spot regarding Clock Speed, head Speed, Data Density, Data separation, Mechanical wear, Temperature ...


5

The drive does not know the correct RPM for any given floppy disk and it does not need to. The drive rotates all floppies inserted to it at the speed the drive is manufactured to run, and thus different systems may rotate the floppies at different speeds by design and it also means drives may not be interchangeable between systems due to their differences. ...


2

In practice no. Overclocking the drive RPM has little effect without also changing the floppy controller speeds. If you increase RPM, and the data rate is such that it still works with the floppy drive itself, then the problem is that the floppy interface controller also needs to adjust read and data rate by same amount to be able to read and write at ...


7

UV light won't affect the magnetic signal. It will however degrade most plastics. UV has energetic photons, that can break apart the molecules in the plastic, thereby degrading it. This has nothing to do with the magnetic information; merely the fact that the plastic will become brittle dust over time.


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