Help with FAT16 and FAT32

By selios2000

Hero (595)

04-12-2022, 13:14

Hopefully someone can clear this up for me:

I have a 2GB compilation of software for the MSX on my Mac, but once I write it to a 2GB SD Card formatted in FAT16, it only fits 1GB (and a little more) than the 2GB of software that I had.
The same thing happens with a 4GB SD in FAT16, it only fits about 2GB (more or less) of files, but if I format it to FAT32, the 4GB of software that I have on the Mac will fit entirely. Why is that?

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By djh1697

Paragon (1736)

04-12-2022, 14:47

The cluster sizes are different, this might be part of the issue. The AFS and FAT32 systems are not recognised by Nextor, so you are limited to either FAT12 or FAT16.

By gdx

Enlighted (6436)

04-12-2022, 15:59

If you copy the files in several times, you can probably put more because Macs consider the available place badly. It is noticeable when there are many files.

By selios2000

Hero (595)

04-12-2022, 18:00

Do you consider that I can modify cluster size of the SD card when formatting or better I forgot the problem and I live happy...

By Grauw

Ascended (10821)

05-12-2022, 16:00

Did you format the SD card on MSX?

By djh1697

Paragon (1736)

05-12-2022, 22:57

My first play with PC-MSX software download was the formatting on my PC to a card in FAT16, it failed.

Do what Grauw says, boot up into Nextor, with a blank SD card in your device. Then using Nextor basic use _fdisk, and follow the useful instructions.

By gdx

Enlighted (6436)

06-12-2022, 09:36

To format an SD or CF card, use the utility provided with your interface. If you encounter a problem, reformat the card with SDformatter on your PC and try again with the utility provided with your interface.

Be careful not to take a card with too much capacity. Otherwise, it will be formatted in FAT32 or exFAT. Which is not good.

By selios2000

Hero (595)

06-12-2022, 21:40

Thank you all for your comments.
I successfully format my SD cards with an old Windows XP in FAT16 (also a 4GB card).
I think the problem is the cluster size...
I do not have Nextor, I use DOS2 but I will try this option.
Thank you all!

By Manuel

Ascended (19678)

07-12-2022, 07:55

You can always format it on the MSX. No need for any kind of PC for that.

By gdx

Enlighted (6436)

07-12-2022, 09:53

Not always. Some utilities crash when there is a problem in the partition table or the card has exotic formatting or partitions.

Selios2000 is miserly in detail. We don't know what interface he uses. It's strange because it seems to have the same problem as with the Sunrise CF/IDE with its original firmware. Only half of the partition is usable in FAT16.

By selios2000

Hero (595)

07-12-2022, 11:06

gdx wrote:

Not always. Some utilities crash when there is a problem in the partition table or the card has exotic formatting or partitions.

Sorry for not being accurate.
I use a Zemmix Neo with the last firmware 3.9.1 (I also used 3.8.1). I boot the MSX with DOS2 and Multimente. And I format my SD cards (2GB and 4GB) with a Windows XP selecting FAT16 (FAT) with predetermined cluster size, and then I put the files to the SDs with my Mac. My Mac (and Windows) recognizes the whole size of the SD, but once the files are being copied to the SD, it seems that their size are doubled and the SD runs out of capacity more or less at half its original capacity (I repeat, the whole size of the SD is detected but files "fatten in size" when copying). For example, one 2GB SD card stops (it's full) at 1,14GB of total size of files from the Mac, one 4GB SD card at 1,63GB.
I must also say that dsk files (720KB) "occupy" less than smaller files. For example, I have tons of files about music (MBM, MGS, MWM...). One batch of dsk files that is for example a total of 100MB (on the Mac) and one batch of music files that occupies the same 100MB (but here there are much more files), the music files occupy a lot more in the SD when copying.
So, as a final explanation, 100MB on the Mac are much more on a FAT16 SD, but THE SAME on a FAT32 SD.