DEC Professional (computer) - Technical Specifications

Technical Specifications

The PRO-325 and -350 used the F-11 chipset (as used in LSI-11/23 systems) to create a relatively compact single-board PDP-11 with up to 6 expansion slots of proprietary CTI (Computing Terminal Interconnect) bus using 90- pin ZIF connectors. The PRO family used RX50 floppies for storage; the PRO-325 had only floppies, the 350 and 380 also included an internal hard drive. Mainline PDP11s generally used separate serial terminals as console and display devices; the PRO family used in-built bit-mapped graphics to drive their 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 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. For all these reasons, support of the PRO family required extensive modifications to the previous 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 or P/OS, which was 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 J11 chip set (as used in 11/73 systems). A PRO-380 with the Real-Time Interface option was later used as the console on high-end VAX-8800 family systems.