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| author | Rodrigo Arias Mallo <rodarima@gmail.com> | 2025-09-28 20:26:15 +0200 |
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| committer | Rodrigo <rodarima@gmail.com> | 2025-09-28 23:10:55 +0200 |
| commit | fb510ea86be5ceb9e91573890242581fdbd77ad8 (patch) | |
| tree | d819fe40683592008d136727f5a0b03e48dc1164 /210/index.md | |
Diffstat (limited to '210/index.md')
| -rw-r--r-- | 210/index.md | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/210/index.md b/210/index.md new file mode 100644 index 0000000..ca0db76 --- /dev/null +++ b/210/index.md @@ -0,0 +1,26 @@ +Title: Reduce floppy disk size after formatting +Author: rodarima +Created: Sat, 29 Jun 2024 14:40:21 +0000 +State: closed + +The useful space to store files inside a floppy is less than the capacity of the floppy itself: +``` + % mkfs.msdos -C floppy.img 1440 + mkfs.fat 4.2 (2021-01-31) + % stat -c %s floppy.img + 1474560 + % mkdir floppy + % sudo mount -o loop,uid=$USER floppy.img floppy + % dd if=/dev/zero bs=1 count=100M of=floppy/test + dd: error writing 'floppy/test': No space left on device + 1457665+0 records in + 1457664+0 records out + 1457664 bytes (1,5 MB, 1,4 MiB) copied, 0,912079 s, 1,6 MB/s + % echo $((1474560 - 1457664)) + 16896 +``` +It needs a bit more than 16K to store the FAT table, so round it to 32K to allow some clearance for changes in FAT header size. +``` + % echo $((1474560 - 32*1024)) + 1441792 +```
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