Cumulus Corporation (often shortened to Cumulus Corp.) was an American computer peripheral and system manufacturer active from 1987 to 1993. Based in Beachwood, Ohio (a suburb of Cleveland) and started by Tecmar founder Martin Alpert, the company set out to exclusively manufacture expansion products for IBM's Personal System/2 (PS/2) family of computers—mainly RAM expansion cards. It later released cross-platform CPU upgrade cards and memory expansion cards for other platforms besides the PS/2. Beginning in 1990, the company began trading as Cumulus Computer Corporation and began releasing complete systems of their own. Initially a success story for the tech industry in Cleveland, a botched stock launch in 1992 proved disastrous for the company's ailing cash flow situation, and in 1993 the company was liquidated amid massive debt to suppliers and lenders.
Foundation (1987–1988) Cumulus Corporation was founded in Beachwood, Ohio, a suburb of Cleveland, in 1987 by Martin Alpert. Alpert, an M.D. and pulmonologist, was previously the head of Tecmar, a personal computer expansion card manufacturer that he founded in 1974 to manufacture and market his designs for medical diagnostic equipment. Shortly after IBM announced their Personal Computer in August 1981, Tecmar became one of the first third-party manufacturers to release expansion cards for the system. Alpert operated Tecmar as a private business until summer 1986, when he sold it to Rexon, Inc., of Culver City, California, for less than US$2.3 million. Alpert stayed on the board of directors, before leaving in October 1986. He admitted that Tecmar in the years leading up to its purchase lacked adequate "executive-level talent" in its management. Alpert set out Cumulus to first and foremost to design and manufacture peripherals for the Personal System/2 (PS/2), a family of computers introduced by IBM in April 1987, intended as the successor to their earlier IBM PC line. He funded the startup of Cumulus with his own money, purchasing an office in San Diego, California, to house Cumulus' full-time engineering staff.
Cumulus released its first products in August 1987: a multifunction board for the PS/2 Models 50 and 60 called CuRAM and an external 5.25-inch floppy disk drive called Stepping Stone. The Stepping Stone was released to address the PS/2's lack of a 5.25-inch floppy drive (IBM had adopted the newer 3.5-inch standard, developed by Sony Corporation, for the PS/2). Cumulus paired the drive with software and a controller card—the latter containing a specially burned PROM with microcode allowing the Stepping Stone to act as the primary (A:) drive. This opened the PS/2 to a larger back-catalog of IBM PC software; the installers of some contemporary applications on 5.25-inch disks, like Lotus 1-2-3, required being run from the A: floppy drive, as a form of copy protection.
The CuRAM multifunction board was in its bare state a RAM expansion card, available in two variants, 2 MB and 4 MB. Three separate daughterboards plugged into the CuRAM through a pin-header-and-socket arrangement. The first added two additional peripheral ports (one serial and one parallel); the second added a 2.4-kbps modem; and the third offered more memory, up to 8 MB. Through included software and driver files, users may designate the CuRAM's memory as either of three types of memory: extended, Expanded (LIM EMS 4.0), and Enhanced Expanded (EEMS). Certain operating systems like Xenix could take advantage of extended memory, and it also allowed users to allocate RAM drives with more than the available memory within the 640 KB conventional memory of real mode PC DOS. In DOS environments, LIM EMS is useful for storing large blocks of data, while EEMS could be used to run multiple DOS programs concurrently. Critically, more than one CuRAM board could be installed and ran in a PS/2 at the same time, increasing the maximum memory to 16 MB. For the Model 50, this meant that that system could possess more RAM than IBM's prescribed upper limit of 7 MB, while leaving one of its three expansion slots open. Cumulus accomplished this by getting permission by IBM to use one of their reserved vendor ID for the CuRAM.