It can be entirely acceptable and preferred. Knowing your working set size and how your memory is being utilized is a critical part of any systems planning...

It can be entirely acceptable and preferred. Knowing your working set size and how your memory is being utilized is a critical part of any systems planning... and memory is one heck of a lot faster than disk, hands down, no debate there. Not we're not talking necessarily about a ramdisk here or specialized software (though we could be) - we're talking about proper system design with enough ram and tuning to get the response times you need.