I have been battling a sudden increase in the frequency of data corruption incidents, and would like some suggestions in this regard.

For some reason the data in external drives is going bad, ultimately ending with the need for data recovery software like testdisk to salvage data. This first happened with NTFS drives when I used ntfs-3g to write into them. Thinking ntfs-3g could be to blame, I stopped the practice. Then writing to FAT32 partitions also caused problems, so I started mounting them as Read only. Now, the latest episode involves an EXT2 partition.
What actually happenned was I was trying to copy a file from the external drives, ext2 partition to the internal drive's ext2 partition. When the internal drive got full, the copy was interrupted.Next, I unmounted and unplugged the drive. The next time I plugged the external drive, the partitions were not being recognised. I can see the drive in fdisk, but mount operation fails with the file system unknown error. testdisk does not find anything wrong with the partition table. fsck tells me that it is an ext3 drive (eventhough fdisk correctly tells me it is a linux partition). In any case, I allowed fsck to proceed with the ext3 assumption and after a ton of errors and corrections, I have a lot of numbered directories, instead of the older structure.(all the data seems to be there). The previous experiences with NTFS and FAT32 were on similar lines : working fine one moment, and the next time it's gone.

I have used the same external drive in Windows previously without any problems, so can't blame it.

Besides loading all partitions in Read Only mode, does ext3 offer additional protection against data corruption of this kind. Any views on this phenomenon are welcome.

ext3 is a journaling file system while ext2 is a non-journaling file system. ext3 should provide better protection against data corruption. If the write cycle is interrupted, the drive loads from the journal data. The trade off is slower performance in ext3 as your data has to be written to the journal then to the data blocks.

ext3 is actually an expanded version of ext2 which is why fsck "misread" your drive but with no journal to load from, you get the problems you encountered.

HTH
Dave