Ideally I'd just use SD cards; but I have found the details of handling the various densities, block and sector sizes, CRC error-detection methods, security methods, fragmenting, wear-leveling (if any), FAT systems and subdirectory structures, and so on, to be daunting. I'm not going to try anymore unless there's a really simple explanation somewhere. I think the things I need to transfer between the home-made workbench computer and the PC could all go over RS-232, including with the FTDI RS232-to-USB adapter if it's on the newer PC that doesn't have an RS-232 port.
I want something that takes very little code to run it. How did the C64 and other home computers of its era handle the files on floppy discs? (I know the C64 disc drives had their own microprocessor in them.) I tentatively plan on starting with 4MB SPI flash memories in tiny SO-8 packages that I have built onto postage-stamp-sized plug-in cards, then maybe moving up to 16MB, or remotely possibly even 64MB, but definitely not more. This is not for photos, videos, music, bloatware, or any of the other things that take up a lot of storage, but rather for workbench-control source code, assembled or compiled programs, measurements taken, etc.. I'm thinking of something like this (although these are not set in concrete):
- up to dozens, maybe hundreds of files, max (256?), not tens of thousands
- no directories (everything in root)
- no fragmentation. If an edited file doesn't fit where it came from, a longer available area is found for it. If there is none, one or more other files are moved to get enough contiguous blank space
- not necessarily having a FAT. I can imagine various ways to do this.
- names can be long enough to be meaningful, unlike DOS's 8.3. A 31-character limit is reasonable. (Is that what C64 had?)