Small wonder: a breadbox-size computer with up to 1 million bytes of fault-control, semiconductor memory—at 5c a byte. (Sep, 1977)

For technically and/or environmentally demanding applications where processing reliability, or high speed, or both, are essential, HP 21 MX and HP 1000 computers can now contain up to 1 megabyte of memory in modules of 128k bytes.

With up to 1 million bytes of fault-control semiconductor memory, HP’s small computers can go to work in demanding applications where large or disc-based systems were previously needed:
• in rugged environments such as ships and airplanes, or in remote, unattended locations such as offshore oilwell platforms—applications where reliability is critical and downtime must be held to a schedule;
• in applications such as physics and electronics labs, where data must be acquired at speeds beyond those possible with a disc.