of design features made it frustrating to use. For instance, the addressing system is so deeply embedded into the core of the system that simply typing in a new address is an ordeal. First the user clicks on a button, selects the address type, types it in, and then finally clicks OK to have it appear in the message. Disk usage is also a problem because each message is stored as a separate file, requiring 1 kB or more of space in an era where 40 MB and 80 MB disks are still common. Thus a few hundred messages are enough to fill the free space on the drive. Backing up email was likewise almost impossible as a side-effect of the design; the mail was spread out over the network, some of it remote and inaccessible. The system could not know who a user was, because the single-user Mac OS 7 does not require users to log in. Thus documents had to be delivered to a user's machine. This does not work well when the user has two or more machines, making the concept of a universal mailbox difficult to achieve in practice. Even the remote access functionality is doomed by feature interaction. To ensure that all messages are delivered in a reasonable time on a network where machines might appear and disappear at random (when they are turned on and off), AOCE has a 15-minute timeout in which it repeatedly tries to deliver pending messages. If the user is using a dialup connection on a modem, AOCE keeps the line open for a full 15 minutes before giving up on disconnected user, driving up long distance bills to deliver a potentially tiny message. Many of these problems were intended to be solved with the PowerShare server, which acts as an always-on, always responsive super-peer. The basic AOCE protocol notices these machines when attempting delivery, and sends to them first, thereby eliminating the delays and centralizing storage and maintenance. The server was not ready in time for the release, and did not ship for another year. When it did it was likewise slow and resource hungry, largely a side effect of various features of the Mac OS that makes it unsuitable for server applications—a role for which it was never designed in the first place. Cancellation AOCE had one year at Apple's Worldwide Developers Conference in 1995 when it was