Luke Gorrie, on Lambda the Ultimate, links to MIT AI Lab Memo #444, August 1977: “LISP Machine Progress Report”

This informal paper introduces the Lisp machine, describes the goals and current status of the project, and explicates some of the key ideas. It covers the Lisp machine implementation, Lisp as a system language, input/output, representation of data, representation of programs, control structures, storage organization, garbage collection, the editor, and the current status of the work

[...]

The memory is typically 64K of core or semiconductor memory, and is expandable to about 1 million words. The full virtual address space is stored an a 16 million word disk and paged into core (or semiconductor) memory as required. A given virtual address is always located at the same place an the disk. The access time of the core memory is about 1 microsecond, and of the disk about 25 milliseconds. Additionally, there is an internal 1K buffer used for holding the top of the stack (the PDL buffer) with a 200ns access time (see [CONS] for more detail)."

The complete LISP machine, including processor, memory, disk, terminal, and connection to the shared file system, is packaged in a single 19" logic cabinet, except for the disk which is freestanding. The complete machine would be likely to cost about $80,000 if commercially produced. Since this is a complete, fully-capable system (for one user at a time) it can substantially lower the cost of entry by new organizations into serious Artificial Intelligence work.

1 megaword of RAM in 1977, no wonder it cost $80,000.