PRO-350

The Professional 325 (PRO-325) and Professional 350 (PRO-350) were PDP-11 compatible microcomputers introduced in 1982 by Digital Equipment Corporation (DEC) as high-end competitors to the IBM PC.

Like the cosmetically similar Rainbow-100 and DECmate-II (also introduced at that time), the PRO series used the LK201 keyboard and 400kB single-sided quad-density floppy disk drives (known as RX50), and offered a choice of color or monochrome monitors.

For DEC, none of the three would be favorably received, and the industry instead standardized on Intel 8088-based IBM PC compatibles which were all binary program compatible with each other. In some ways, the PDP-11 microprocessors were technically superior to the Intel-based chips. While the 8088 was restricted to 1MB of memory because of its 20-bit address bus, DEC microprocessors were capable of accessing 4MB with their 22-bit addressing (although direct addressing of memory was limited in both approaches to 64KB segments, limiting the size of individual code and data objects). But other factors would weigh more heavily in the competition, including DEC's corporate culture and business model, which were ill-suited to the rapidly developing consumer market for computers.BYTE in 1984 reported that Venix on the PC outperformed the same operating system on the DEC Professional and PDP-11/23.

Further, although the PDP-11 was a very successful minicomputer, it lacked a wide base of affordable small business software. By comparison, many existing CP/M applications (see the Rainbow 100) were easily ported to the similar 8086/8088 chips and MS-DOS operating system. Porting existing PDP-11 software to the PRO was complicated by design decisions that rendered it partially incompatible with its parent product line. Industry critics observed that this incompatibility appeared at least in part deliberate, as DEC belatedly sought to "protect" its more-profitable mainstream PDP-11s from price competition with lower-priced PCs.

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