In the wee hours of yesterday morning, Harvard Arts and Sciences Computer Services (HASCS) technicians implemented the second stage of a multi-part plan to drastically redesign Harvard's e-mail system.

HASCS hopes these changes will correct problems that plagued the system last semester and caused continuous woes among e-mail users.

"We've been trying to get on top of these problems for a while," said Chair of the Standing Committee on Information Technology Paul C. Martin '51, the outgoing dean of the Division of Engineering and Applied Sciences.

"I certainly hope and expect that [these changes] will lead to substantial improvements, but we're cautious enough to know it will be some time until we know what is happening and we know volume will continue to rise," Martin said. "We're optimistic."

The changes, which HASCS began at the end of January and should complete in mid-February, represent a theoretical shift in how Harvard deals with e-mail.

Previously, Harvard's e-mail system--which handles between 200,000 and 350,000 incoming messages a day--relied mainly upon two powerful computers, one for loggingin and the other for distributing e-mail.

With the new system, three machines will distribute mail and four machines will handle log-ins. The new system is faster and will provide "redundancy," meaning one machine's crashing will not bring down the entire system.

"There were two major problems of concern. When there was a slight problem, we would have to take down our entire system [and] we were susceptible to mail spikes," said Franklin M. Steen, director of FAS Computer Services. Such problems occur when a high volume of mail results in a clogged server, said

"In designing a central system, you effectively have two options: one big box or a bunch of little boxes," said Director of Residential Computer Support Rick Osterberg '96. "We had used the big box option, but we hit the point where one big box just couldn't keep up."

These changes are in response to student and faculty complaints last semester, when checking and sending mail under Harvard's often staggeringly slow e-mail system became a tedious task.

"It has become blindingly evident that our current infrastructure is not capable of delivering the level of performance necessary to meet the quality of service level you all require," stated a technical statement from HASCS last month.

Last semester, HASCS evaluated e-mail service at three-minute intervals and found that the e-mail system suffered unacceptable delays 18 percent of the time in a typical day, Steen said. ,

As a result of yesterday morning's changes, when users log into FAS, they will be randomly, but uniformly, distributed to one of four new machines. This approach is known as "round robin." These four machines collectively represent twice the computing power of the old FAS machine.

Mail delivery is now handled by three machines instead of just one.

In the third and final stage of the improvements, HASCS will transfer users' home directories and mail directories to a new, faster "disk array"--a machine that stores e-mail.

The transfer will require at least two all-night down times, but will produce the most significant increases in speed, Steen said.