A late contribution, from me, but might be useful. There are 3 levels of formatting on a floppy disc, only two of which are accessible to the user. They are:
- A low-level format added by the manufacturer. Data is written to a series of concentric tracks, not a gramophone type spiral, that are organised into sectors containing blocks. The number of tracks, blocks and sectors are determined by the disc manufacturer, and the sector start points identified by a special string of data. When a read or write is requested, the disc controller moves the head to the correct track, identifies where the sector starts from the special code, and then knows the next 'n' blocks are user data.
- The next level is available to the user. A 'full format' builds on the low-level format to add a file system to the disc. File systems are understood by the operating system. They provide filenames, permissions, error checking, and high-level organisation of the disc. Some layouts optimise write performance, others read. Some provide speed, others can get more data on the disc. Floppy discs are low capacity, so a lightweight file system is used. FAT is almost universal on floppies, but it's only good for small discs. Big discs are formatted with something smarter, NTFS, ext3, APFS.
- As a full 'Full format' takes a long time – setting up from scratch removes whatever is on the disc already and checks the low-level format is OK – there's usually a 'Quick format' option. This assumes that the existing file system and low-level format are both in good order. It unhooks existing data, and declares the blocks 'free' so they can be reused. Not a way of deleting private data because it's still available to anyone with the right software.
When a Microsoft disc malfunctions, the first thing to try is CHKDSK: read the manual! CHKDSK is smart enough to detect file system and low-level format errors. It's fairly effective at fixing file system errors provided they're not caused by low-level format or physical faults. These are dealt with, up to a point, by patching them out. If a bad sector is identified, it tells the file system not to use it. (Most floppy and hard discs have a few bad sectors from new.)
However, CHKDSK isn't perfect, so the next step is a Quick Format. Don't expect much! The main advantage of a quick format is speed, and with luck, the error might be a simple one it can fix. Usually not, in which case a full format is called for. Again, read the manual. format run from the command line may be able to force extra checks.
Here's the bad news. Floppy discs went out of fashion because they're unreliable. Hot stuff when they first appeared, but the design rotates a delicate magnetic surface inside a touching sleeve, and the head physically rubs the surface. They're vulnerable to particles getting inside the envelope, to dirt on the head, and to worn heads. Quality control was good rather than perfect, and this showed up when organisations bought discs in thousands. Even in the best makes it was usual to find a few discs per hundred that quickly failed. Same problem with disc drives: a proportion of them would rough up new discs, causing early failures. Grubby locations had higher failure rates than clean offices. Floppies were reasonably reliable, but frequent backups and careful handling were insisted on. If a disc showed any sign of malfunction, it would be ditched immediately. The reason is that debris from a scratched surface can damage the head, and a damaged head will damage other discs as well.
As floppy discs are still widely available and inexpensive, don't mess with persistently wonky ones. Throw them away.
If a system fails to format a few new floppy discs, the disc drive may be damaged. Change it or buy a new computer.
Though they have different flaws, memory sticks are a far better alternative. They're immune to dirt and magnetic fields, and hold massively more data. But the computer has to be modern enough to support them!
Dave
Edited By SillyOldDuffer on 14/05/2023 09:55:01