1. Can the Trojan-horse attack work in a system protected by capabilities?
2. When a file is removed, its blocks are generally put back on the free list, but they are not erased. Do you think it would be a good idea to have the operating system erase each block before releasing it? Consider both security and performance factors in your answer, and explain the effect of each.
3. How can a parasitic virus (a) ensure that it will be executed before its host program, and (b) pass control back to its host after doing whatever it does?
4. Some operating systems require that disk partitions must start at the beginning of a track. How does this make life easier for a boot-sector virus?