The Pro compatibility

[vol.litwr]

I am curious, did the Pro have any compatibility issues? Is it possible to run RSX-11M-Plus on it? It seems that RT-11 runs quite well on the Pro - all programs run without issues. Thus, this contradicts Wikipedia's claim that "the PRO cannot run standard PDP-11 software without modification". It seems that P/OS can also run RSX-11M-Plus software.
IMHO the problem was rather the small number of the released computers. So nobody tried to port e.g. RSX-11M-Plus to the Pro.
I am also curious is there a way to put files on the P/OS disk images? The putr program can only read FILES-11 format.
Thanks in advance.

 

[krebizfan]

I thought the problem was P/OS which did require modification to software. Note that the RT-11 that works on the Professional is 5.something or later which came out at least a year after the Professional. The FAQ isn't certain and neither am I. DEC seemed to have realized that the idea of having a completely separate software stack for the Professional was not going to happen.

The FAQ mentions a few of the problems with the Professional. See https://en.wikiversity.org/wiki/DEC_Professional_(computer)

 

[hush]

my understanding is that RSX11 would require nontrivial modifications to run on pro series machines, there was apparently a report on multi-tasker that it had been done by someone at DEC, but had been a major undertaking

 

[NeXT]

Same chipset, substantially different hardware.

All other I/O devices in the PRO family are also different (in most cases, radically different) from their counterparts on other PDP-11 models. For example, while the internal bus supports direct memory access (DMA), none of the available I/O devices actually use this feature. The interrupt system is implemented using Intel PC chips of the time, which again makes it very different from the PDP-11 standard interrupt architecture. For all these reasons, support of the PRO family requires extensive modifications to the previously-existing operating system software, and the PRO cannot run standard PDP-11 software without modification.

DEC Professional (computer) - Wikipedia

en.wikipedia.org

There was paranoia that it would undermine sales of their low-end '11 systems so it's quite deilberately crippled.

 

[tradde]

So why even make it or sell it?

 

[hush]

well, wasn't the DECmate series more or less the same idea? a hobbled version of the Big Boy architecture meant to be "compatible enough" for the secretaries and lawyers they were being deployed for?

 

[tradde]

I guess. Back then I did not use any of these so don't know for sure what DEC was thinking.

 

[hush]

i don't disagree with you to be clear, the rainbows, pros, and DECmates are all neat machines in their own right but objective market failures (and definitely frustrating at times in how not-quite-compatible they are), it just seems like DEC saw a niche in all three instances, maybe even where there wasn't really one

 

[krebizfan]

All three machines were potentially good ideas but released a few years too late.

The DECmates were about the same price as the PDP-8 word processors from 5 years before. It was tough sledding for the PDP-8s and the DECmates had even tougher competition.

The Rainbow was the perfect micro for 1980.

The Professional was the worst of the three. The whole advantage of the design was the ability to run PDP-11 software. Remove that and one has a machine that has no point. DEC canceled it and then let the engineers turn it into something somewhat useful.

 

[tradde]

I think DEC wanted to get into the PC market and thought these machines would help them get there. Somewhat compatible with bigger machines but could be used in the office. Too bad DEC made poor choices towards the end and we know where they ended up.

 

[AK6DN]

I guess. Back then I did not use any of these so don't know for sure what DEC was thinking.

Your mistake is thinking DEC was some monolithic corporate entity with a single rational decision maker.
It started that way when Ken Olsen was in charge, but as it evolved into Product Lines and divisions it became a conglomerate.
Product lines competed against other product lines. Product line managers even competed among themselves within the same product line.

Ken Olsen famously even said words to the effect that no individual would ever need a computer in their home: https://quoteinvestigator.com/2017/09/14/home-computer/

 

[tradde]

Same thing when I was at Sperry. Products competed against products. I even remember them adding a wire to cause the cache in a machine to invalidate every so often to slow the machine down. By "buying" the upgrade the tech would remove the wire. Later it was changed to a key-lock. Same thing. And was even worse when Sperry merged with Burroughs. There were many products by both that competed and were nearly the same on both sides. One got so far to almost being released and was cancelled at the last minute. After a group of us had flown out to Minn to work with this new system. Amazing.

 

[hush]

Ken Olsen famously even said words to the effect that no individual would ever need a computer in their home: https://quoteinvestigator.com/2017/09/14/home-computer/

correct, but not in the sense that we mean "personal computer" now, he was more envisioning something along the lines of multics, a central computing resource provider that users could dial into from a home terminal, well before the era of home PCs

 

[AK6DN]

correct, but not in the sense that we mean "personal computer" now, he was more envisioning something along the lines of multics, a central computing resource provider that users could dial into from a home terminal, well before the era of home PCs

Wikipedia: "In 1977, referring to computers used in home automation at the dawn of the home computer era, Olsen is quoted as saying "There is no reason for any individual to have a computer in his home."[12][13][14][15][16] Olsen admitted to making the remark, even though he says his words were taken out of context and he was referring to computers set up to control houses, not PCs.[14] According to Snopes.com, "the out-of-context misinterpretation of Olsen’s comments is considered much more amusing and entertaining than what he really meant, so that is the version that has been promulgated for decades now"."

IMHO he was even MORE WRONG saying no one would need computers for "home control" rather than for "personal computing".
Embedded home control applications of individual microcomputers dwarfs the personal computer market.
Wonder of what he would think of the phone that everyone is carrying around now that would run rings around the VAX-11 systems of the 70s and 80s.

 

[hush]

Wikipedia: "In 1977, referring to computers used in home automation at the dawn of the home computer era, Olsen is quoted as saying "There is no reason for any individual to have a computer in his home."[12][13][14][15][16] Olsen admitted to making the remark, even though he says his words were taken out of context and he was referring to computers set up to control houses, not PCs.[14] According to Snopes.com, "the out-of-context misinterpretation of Olsen’s comments is considered much more amusing and entertaining than what he really meant, so that is the version that has been promulgated for decades now"."

IMHO he was even MORE WRONG saying no one would need computers for "home control" rather than for "personal computing".
Embedded home control applications of individual microcomputers dwarfs the personal computer market.
Wonder of what he would think of the phone that everyone is carrying around now that would run rings around the VAX-11 systems of the 70s and 80s.

i'm not sure i would agree, the home automation market has only relatively taken off (on a large scale at least) whereas PCs have been a staple of the american home longer than i've been alive

 

[AK6DN]

i'm not sure i would agree, the home automation market has only relatively taken off (on a large scale at least) whereas PCs have been a staple of the american home longer than i've been alive

Well, I have smart light bulbs controlled by an app on my phone. Is this not 'home automaton'?
Garage door opener, same. Alarm system, same. Home HVAC system thermostat, same. Solar power system, same.
Not my frig tho, I have to draw a line in the sand somewhere.

Only have two PCs, tho, a desktop and a laptop.

 

[pbirkel@gmail.com]

Same thing when I was at Sperry. Products competed against products. ... And was even worse when Sperry merged with Burroughs. There were many products by both that competed and were nearly the same on both sides. ...

As a technical sortta guy this sort of thing looks dumb _however_ having just read a history of ICL -- the poster child for merger-upon-merger -- it seems clear that products are driven by customers, and then by the intent to retain a given customer base over time through improved performance/cost. Some mergers or acquisitions were purely to acquire a new customer base -- either into which to sell existing lines of acquirer-company equipment or to gradually migrate from the acquired-company HW to the acquirer-company HW -- perhaps in the next-gen system. Sometimes that could happen more quickly through ISP emulation, other times through literal usurpation. In the meantime, two lines of more-or-less comparable HW tailored to their particular customer base so no immediate economy of scale (although the immediate cash flow situation might be improved). And potentially two next-gen design groups in competition. It's complex. (And yes, product line competition within the same company is true across many industries AFAICS. Sometimes it appears to be quite intentional strategy at the senior management level, at least "up to a point". But other times such behavior seems more from lack of oversight and power-to-the-fiefdoms. Organizations are complex, too.)

 

[vol.litwr]

I think DEC wanted to get into the PC market and thought these machines would help them get there. Somewhat compatible with bigger machines but could be used in the office. Too bad DEC made poor choices towards the end and we know where they ended up.

IMHO the Pro was rather a workstation class than PC. If they had provided better software, the Pro would have been sold much better. The most odd thing for me was the decision to add the CP/M compatibility board that put the Pro on the level of cheap 8-bit machines.

 

[pbirkel@gmail.com]

IMHO the Pro was rather a workstation class than PC. If they had provided better software, the Pro would have been sold much better. The most odd thing for me was the decision to add the CP/M compatibility board that put the Pro on the level of cheap 8-bit machines.

Software base ... even if only 8-bit ... I presume. Agree that it was intended as a workstation-class machine, not for the secretarial pool ...

 

[czunit]

Um....

1) POS *is* RSX11M+. It is multi user, multi task, and all that.
2) The main thing it was missing was the Split I/D capability. This was probably so they could have one install media stream for the 350 (F11 based) and the 380 (J11)
3) Lack of I/D means there is no disk cache. Which is a pity because the disk controller is dog slow.
4) The menu system was indeed pretty stupid, but it was designed for an office worker who had no clue how DOS type commands worked. Oddly enough if you look at it from a user standpoint it was pretty useful.
PC/XT and AT systems had menu interfaces just like this.
5) You can always run the POS Toolkit and get a real DCL console.
6) By POS 3.2 the features in POS were exceeding those of the latest M+. There were subdirectories, mountable sub-volumes, and a very interesting split to allow multiple users to each have their own environment on a PRO. There is some good stuff in there I wish was in real M+

So it wasn't really bad software. SPSS/X (which is now out there) was good, as were some other applications I have seen. If you can live without I/D space and the lack of cache for the disk it's a nice little system. Just upgrade the internal memory boards to 256k chips and you can have 1mb of memory for the 350 or the 380 right out of the box. I wonder if it's possible to bring the CTI bus memory card up to 1mb instead of 256k, but to be honest people have built 4mb memory cards that work in the memory expansion slots with no issues.

The controllers are weird, but weird in the way that they are really more like RK05's and RL01's than MCSP devices. Well, more like RX01 drives, they do not use DMA and pretty much live on interrupts. Should be possible to develop a basic disk device driver for them. Set the printer port to be a serial console (jumper on the DB9) and you have an ODT console.

You can hook up two Gotek/Flashfloppy units to replace the RX50's and load a lot of software, and Dave Gesswin's MFM emulator can suck data off real Pro disks and emulate POS volumes.g

Hm. I wonder if the simplest way to start would be to write a driver for pdp11Gui and see if I can do things on the disk drive with that.