Computers are bricks that compute

Lenovo is marketing their "ThinkCentre M72e Tiny Desktop", a desktop PC that runs Windows. Yet the Lenovo M72e is quite different from the IBM model 5150.

The Lenovo is a more capable machine than its predecessor of 30-plus years ago. It has a processor that is faster and much more powerful, It has more memory, and larger storage capacity. But those are not the differences that catch my attention.

Unlike the typical desktop PC, the Lenovo M72e is a small unit, just large enough to hold its contents. This small factor is not new; it was used for the Apple Mac Mini. Small and sleek, it almost disappears. Indeed, one can mount it behind a flat-screen monitor where it is out of sight.

The original IBM PC was expandable. It had a motherboard with five expansion slots and room for internal devices like disk drives.

The IBM PC (and PC clones) needed expansion options. The basic unit was very basic: operable but not necessarily useful. The typical purchase included a video card, a display monitor, the floppy controller card, floppy disks, and PC-DOS. (Hard disks would be available with the IBM PC XT, released two years later.)

Other expansion options included additional memory, a real-time clock, terminal emulator cards, and network cards. The PC was a base, a platform, on which to build a tailored system. You added the devices for your specific needs.

IBM designed the PC to be expandable. The idea fit the sensibilities of the time. IBM had sold mainframes and minicomputers with expansion capabilities; its business model was to sell low-end equipment and then "grow" customers into more expensive configurations. Selling a basic PC with expansion options appealed to IBM and was recognized as "the way to buy computing equipment" by businesses. (The model was also used by other computer manufacturers.)

Today, we have different sensibilities for computing equipment. Instead of base units with expansion adapters, we purchase a complete system. Smartphones, tablets, and laptops are self-contained. Video is included in the device. Memory (in sufficient quantity) is included. Storage (also in sufficient quantity) is included. Additional devices, when needed, are handled with USB ports rather than adapter cards.

Desktop PCs, for the most part, still contain expansion slots. Expansion slots that most people, I suspect, never use.

Today's view of a PC is not a platform for expansion but a box that performs computations. The smaller form-factors for PCs fit with this sensibility.

That is the difference with the Mac Mini and the Lenovo M72e. They are not platforms to build systems. They are complete, self-contained systems. When we need additional capacity, we replace them; we do not expand them.

Computers today are bricks that compute.