TRAM (Transputer Modules)

While the Transputer was an ingenious thing itself, INMOS went one step further and created the TRAM, short for “TRAnsputerModule”. A small 1.05 by 3.66 inch PCB providing a Transputer and some RAM and featuring just 16 PINs to the outside.
This so-called size-1 TRAM then was also available as double, three, four or even 8 times bigger version, called size-2, size-3, size-4 or size-8 accordingly. Original specs are available here.

Initially a (compute) TRAM normally consisted of a Transputer (socket) and memory. The amount of memory went up from mere 32k to multiple megabytes over their evolution.

Later peripheral TRAMs were developed offering features like RS422, graphics, network or SCSI interfaces.

A list of Inmos TRAMs can be found here. A selection of third party TRAMs are listed on this page.

TRAMs are quite fragile, so make sure to read the "Handling TRAMs" article on geekdot.com.