I have implemented level 5 software raid (of 4 partitions on a SINGLE external hard disk). Implementing it on a single hard disk doesn't serve much purpose, I understand, but I did it for demonstration purpose only. The problem is when I read from the raid device into my laptop's hard disk, the time taken to transfer a 900 MB file is about 4 minutes (4 GB RAM) whereas the rime taken to transfer it from a pen drive is 43 seconds. Isn't raid supposed to work faster. However, the write to the raid device is faster than to a pendrive.

Shouldn't it be taking data in parallel from the 3 partitions (as even a single disk has multiple heads) ?

No most disks have 1 head and when they have more heads these can not move independently so by implementing a software raid on 1 disk the heads have to move more instead of less.

Thanks