page_title: DEC Professional (computer)
section_title: Technical specifications
hierarchical_section_title: DEC Professional (computer) / Technical specifications
caption_attribution_description: English: CPU DEC "Fonz-11" (DC303E and DC303F)
context_page_description: The Professional 325, Professional 350, and Professional 380 were PDP-11 compatible microcomputers introduced in 1982 by Digital Equipment Corporation as high-end competitors to the IBM PC.
context_section_description: The PRO-325 and -350 used the F-11 chipset (as used in LSI-11/23 systems) to create a single-board PDP-11 with up to six expansion slots of a proprietary CTI (Computing Terminal Interconnect) bus using 90-pin ZIF connectors. The PRO family used dual RX50 floppy drives for storage; the PRO-325 had only floppies, and the 350 and 380 also included an internal hard drive. Mainline PDP-11s generally used separate serial terminals as console and display devices; the PRO family used in-built bit-mapped graphics to drive a combined console and display. 
  All other I/O devices in the PRO family were also different (in most cases, radically different) from their counterparts on other PDP-11 models. For example, while the internal bus supported direct memory access (DMA), none of the available I/O devices actually used this feature. The interrupt system was implemented using Intel PC chips of the time, which again made it very different from the PDP-11 standard interrupt architecture. For all these reasons, support of the PRO family required extensive modifications to the previously-existing operating system software, and the PRO could not run standard PDP-11 software without modification.
  The default PRO-3xx operating system was DEC's Professional Operating System (P/OS), a modified version of RSX-11M with a menu-driven core user interface. Industry critics complained that this user interface was awkward, slow, and inflexible, offering few advantages over the command-line based MS-DOS user interface that was coming into widespread use.
  Other available operating systems included DEC RT-11, VenturCom Venix, and 2.9BSD Unix.
  Later, the Professional 380 (PRO-380) was introduced using the much faster J-11 chip set (as used in 11/73 systems). However, due to clocking issues on the motherboard, the J-11 chip ran at 10 MHz instead of 16-18 MHz, thus making the PRO-380 slower than a stock 11/73 system.
  The DEC Professional Series PC-38N was a PRO-380 with a real-time interface (RTI) that was used as the console for the VAX 8500 and 8550. The RTI has two serial line units: one connects to the VAX environmental monitoring module (EMM) and the other is a spare that could be used for data transfer. The RTI also has a programmable peripheral interface (PPI) consisting of three 8-bit ports for transferring data, address, and control signals between the console and the VAX console interface.
caption: DEC "Fonz-11" (F11) Chipset
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