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DEC Professional 350 Computer with stand

Manufacturer Digital Equipment Corporation
Model Professional 350
Date Announced
Date Canceled
Number Produced
Country of Origin USA
Current Value $25-$200
Processor J-11 chipset
Speed Unknown
RAM 512K-1MB
ROM Unknown
Storage 2 5.25" floppy drives, 5MB or 10MB hard drive
Expansion Several expansion slots
Bus Proprietary
Video 132x25 text, graphics (optional)
I/O Serial ports
OS Options P/OS, CP/M-80, RT-11, Venix (an early UNIX variant)
Notes The DEC Professional 350 was Digital's answer to the IBM PC for a business market (the Dec Rainbow was more geared to the educational and home markets). It was more expensive and less popular which made competing difficult.
Related Items in Collection Color monitor, lots of original software, several add-on cards including a phone management system, computer stand with adjustable keyboard and monitor trays.
Related Items Wanted Additional software and OS'

The Digital Equipment Corporation envisioned the Professional 350 as a high-end competitor to the IBM PC. The machine was very well engineered with a rugged chassis housing easily swapable components as well as a unique single spindle, dual head assembly floppy system. The Pro 350 sported an J-11 chip set and was basically a micro-PDP 11.

The Pro-350 in my collection is fully functional and has a complete set of manuals and a fair amount of software on diskette. This machine runs P/OS, the Professional Operating System although other Operating systems were available including RT-11 and a UNIX variant. The machine has a 10MB hard drive as well as the dual floppy drives and uses a fairly rare color display.

DEC Pro 350 computer work area

This machine is also unusual in that it comes with the DEC workstation stand. This stand has a rear mounting for the CPU, a keyboard/work surface and a raised monitor platform. The monitor can be raised and lowered using a peddle mounted on the base of the rolling unit.

This computer was donated by Pete Hansen.

(Submitted September 5, 2012 13:23:52 by (a href=mailto:nickzNOSPAM-at-eskimo-dot-com)Nick Z(/a))

DEC was rather tight-lipped about Pro3xx features so we often had to figure it out ourselves -- one of their reps said point-blank that direct modification of the video memory was not possible, but it was hinted at in the Technical Manual so I wrote a screen editor using that feature. The floppies could be easily formatted on a Rainbow, and the QIO code for doing so on the Pro was in the driver source code, but this was officially not possible also.

If DEC had a different attitude, these machines could have become the standard instead of the IBM PC's, which were still using cassette tapes while the Pro had 4MB of RAM, bitmapped display, multitasking, hard drives, a mature operating system and so forth, in 1983. (But I usually use/used the Pro/Tool Kit which was an RSX11M-Plus command-line environment, rather than the menu-driven system -- my Pro's main hard drive is currently dual-OS, shared between P/OS and lightning-fast RT-11 v5).

(Submitted September 5, 2012 13:22:33 by (a href=mailto:nickzNOSPAM-at-eskimo-dot-com)Nick Z(/a))

Hi David, I still have my Pro350; we bought them for about $2000 in Sept. 1983 and were also told we were the first incoming S.I.T. class to have to get them. Though the system may have been around since 1982, it was still a work in progress -- we were at first to get Pro325's without a hard drive then last minute they decided to make it a 350 with the 10MB hard drive and the ponderous P/OS V1.5 operating system (written in Pascal!). We also got the Diskette and Hard Disk upgrade version of P/OS V1.7 and then later the V2.0 and V3 upgrades. Finally they decided to release the source code on microfiche only.

(Submitted June 10, 2011 12:19:06 by David)

This brings back memories. My first year of college at Stevens Institute Of Technology was also the first year that all new freshman had to purchase a computer: The Pro 350. That was 1985. When I left the school, I sold it for $3,500. This was more than the school charged for it, so I felt pretty good about it. Of course, I wish I still had it now.

(Submitted December 29, 2010 08:35:47 by Henry Collins)

I have very fond memories of the Dec Pro 350 as it was my first computer purchase back in 1981. I purchased it with the LA-100 printer and printer stand. I paid $10,000 for the whole package, and that was with a friend's employee discount. I used it largely as a word processor and to provide offline text storage for my Memorywriter 630C which I hardwired to the Pro350 via the RS232C ports. I also wrote a regular monthly column on the DEC Pro 350 in a magazine called Hardcopy. The column was called Hands on. My machine came with a 5Mb harddrive and dual 5 floppies. Dec quickly upgraded the drive to 10Mb. It was indeed a great computer, one of the best machines ever made.

(Submitted March 1, 2010 11:12:40 by (a Bradley(/a))

There was also a DEC O/S version of Unix on the Pro 350, called ProV7M. I have the SW and manual. Venix was faster because it used the Unix V6 file system instead of the V7 code used in ProV7M. I have a Pro 350 with lots of associated HW and SW that I'm hoping to dispose of as soon as I can determine the condition to describe it accurately. It worked fine when last used, more than 15 years ago.

(Submitted December 7, 2009 14:10:42 by anasana)

Hi to all again! Tarik, where are You now?.. This september I have been ported the Tarik Isani project Digital Xhomer emulator under Windows 7 & XP. Added the virtual keyboard (LK201 and MC7004) and Russian Electronika 85 (MC0585) boot rom. Usual win-menu driven commands, telnet access (emulator as a server), interleaving master. Today I have an instruction step-by-step how to 100% read data from the DEC 350/380 floppies to file-images on usual PC and have a lot of dumped software from our diskettes. Please help, if some one has the: - Real DEC Pro 380 or boot ROM dumps from chips. - DECNA card internal boot ROM dumps. - Z80 softcard internal boot ROM dumps. - Diskettes with any software for Pro. Feel free to ask me in any time and by any case! Oleksiy. Please in copy to

(Submitted October 23, 2009 09:29:37 by footdoc)

Dec Pro 380 available

(Submitted February 23, 2009 14:57:27 by Kendall)

my dad use to work for digital and love the stories that he has told me. if anyone remembers anything about using any system that you may have used please email them to me, I'm planing to make a blog entry on any that you sent to me.

thanks in advance,

Kendall Seabury

(Submitted November 11, 2007 09:05:28 by Tom lake)

I have a PRO 350 but the hard drive was wiped and I don't have the original disks to laoad the software. Is there any way I could get disk images from you to allow me to set up the system? I have a set of 21 P/OS disks I got off the Internet but they're not bootable.

(Submitted October 9, 2007 23:26:55 by JMC)

The description on this web page describes the Pro-350 as having the J11 processor chip. It was the Pro-380 that had the J11. The Pro-350 used the earlier F11 chip set. The Pro-380 was a pretty decent RT-11 platform, though taking advantage of the graphics required us to create some special device handlers.

(Submitted July 11, 2007 09:10:41 by Robert Winslow)

I have old laboratory data collected on various DEC computers, all on floppies that were read on DED Pro 350/380 machines. I am looking for a machine that can read the floppies and output the data to some more convenient media. I would be very happy to hear from anyone with an operating machine interested in selling to me.

(Submitted April 16, 2006 17:07:09 by (a

I have 3 Pro350 and one Pro 380 with a lot of archive stuff on them. All working. The 380 and one 350 has upgraded memory done by myself, and both have double RD53's since diskettes are in the other Pro's I also have a Vax Station 2000 with 2 RD54 harddrives and a Tape station. All is ethernet'ed together. That is , one Pro DECNA- K has stoppet working, so this Pro has RS232 into the VAX. I also tried to send doc files from Pro 350 to a PC, via RS232, it worked, but it involved a lot of work fixing the text ! The Vax Station 2000 is linked to PC 10/100Mb Lan network, and a VMS modulator program on PC interfaces the VAX ! One of theese days I will copy all old valueable files from the Pro 380/350's to the extra RD54 on my VAX, and take it from there. I have a lot of documentation, 4- 5 Meters and 3 working PRTIL, 2 Phone systems , original stand, 3 working color monitors, one green, and a lot of sw, including the Decus tapes, among others.

(Submitted February 24, 2006 19:22:43 by (a href=mailto:)Tarik(/a))

I wrote an emulator for this system, based on SIMH:

(Submitted September 25, 2005 05:27:29 by Buck)

My partner aquired a Digital Professional System 425. I dont see it listed. It had a 5mb HD, 1 5 1/4 floppy single sided low density. It was built like a tank. She got it at an auction. I never used it much, just got it started for her. Took waaay too long to boot. She paid very little and it became a converstion piece.


(Submitted July 18, 2005 06:55:52 by anasana)

I have a full Russian analog of this computer it names: Electronika MC-0585 with OS RT-11 and PROC. I have about 30 5,25 diskettes and manuals (russian lang.). I`m search an emulator of this system and tools to create an images of disks. See all You later!

(Submitted June 9, 2005 10:49:23 by Tom Lake)

I'd bein interested in one of those stands if you still have any for sale!

(Submitted March 10, 2005 15:14:06 by Matt Patoray)

Hi, Mary if you would like to sell me one of the workstation stands i would be interested. Also does anyone have the DEC Daisy whell printer that went with this computer.



(Submitted January 12, 2005 16:27:09 by mary)

I have several, new in box, DEC workstation stands. Any idea of the current value and how to best sell them?

(Submitted November 22, 2004 23:37:21 by Jesse Bunch)

I have several DEC Pro 350's and monitors. Any idea of the current value and how to best sell them?

(Submitted September 26, 2004 07:44:04 by Fred)

Nice display stand! I have a fair amount of DEC stuff myself, but have never seen the workstation stand setup.. neat!

If you'd like to exchange (images of) diskettes, let me know!


(Submitted September 5, 2004 15:38:42 by thom)

i just wanted to say that i am working on a Linux distro that does not yet have a title. the emphasis is on a killer GUI, and i was thinking of calling it the Professional Operating System. unfortunately is also stands for POS or Piece Of Sh!t which is not an acronym you want to have. so in my research i'm surprised to come across this page which tells me that there is already a Professional Operating System, which also has the unfortunate P/OS designator!

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