Disk access is slower than memory access (duh!) Simultaeneous write/write operations cause data corruption. Therefore locking must occur. Locking is slow Use the disk in concentrated bits, meaning do all]]>your writing together. Do Not Read Large Files Into Memory! Do Not Read Small Files From Disk! Employ caching to access frequently used data]]> stored in memory Try and put write operations where they will]]> cause the least loss in user experience (remember,]]> web pages are chunked!)