Cannot write to MS-DOS FAT12 with MacOS Ventura

Ko van den Berg wrote:

I do have a device (solar panel converter interface) that uses FAT12 as file system. When I connect it to my MacBook Pro with Ventura, the device is shown as 'read-only'.

Is that because Ventura cannot write to it, or is the device really write protected?

FWIW, Macs have supported FAT12 for many years and normally can read/write to it. The device may be write protected.

Here's a screen shot of Disk Utility with a USB Flash Drive.

Just to add, Macs can write FAT12 to USB Flash Drives as well, as I showed in the screen shot.

The FAT12 is the file system on a floppy disk.

The number “12” is derived from the fact that the FAT consists of 12-bit entries.

The storage space on a floppy disk is divided into units called sectors. In larger storage devices, a bunch of sectors form a cluster

So in effect, the issue is not macOS Ventura or any other older version of macOS but rather the Drive Format that this solar panel converter interface uses

The Mac128 was launched in 1984, and most certainly could NOT read FAT disks - it used an apple-proprietary 400KB single-sided disk format using the same Woz-designed encoding scheme used in the Apple 2. Only with later Macs with "superdrives" could PC/MSDOS disks be read/written.

I light of Addition Information provided, you may consider that as a possibility

Keep in mind that the maximum file size with FAT12 with 4KB clusters is 16 MB, and with 8K clusters, it is 32 MB.

NotMyRealName62 wrote:

The Mac128 was launched in 1984, and most certainly could NOT read FAT disks.

While true, the question was about Ventura and at the very least, Macs made in this century. 🤣😎

For the curious, the first Mac that could read FAT formatted drives was the Macintosh SE, released in 1987.

Yes, as I said. macOS and for that matter OS X, and possibly back to the first Macintosh 128k in 1985, has supported FAT12.