In a FAT32 system using 512-byte sectors, a 123 KB file occupies how many sectors?

• A. 240
• B. 246
• C. 248
• D. 250

Answer: (B)

In FAT32, a file’s storage is allocated in clusters, which are groups of sectors. The number of clusters a file needs is the ceiling of (file size in bytes) divided by (cluster size in bytes), because a partial cluster isn’t possible—every file must occupy whole clusters. The total sectors used is then (number of clusters) times (sectors per cluster).

Here, 512-byte sectors and a cluster size of 1 KB means each cluster is 1,024 bytes and contains 2 sectors. The file size is 123 KB, which is 123 × 1,024 = 125,952 bytes. Dividing by 1,024 bytes per cluster gives exactly 123 clusters (no partial cluster). Multiply by 2 sectors per cluster: 123 × 2 = 246 sectors.

So the 123 KB file occupies 246 sectors. Note that if the cluster size were larger, the number of sectors would differ (e.g., with a 4 KB cluster, it would be 248 sectors). The key idea is that files consume whole clusters, and the total sectors depend on the cluster size chosen for the FAT32 volume.