More pro for the DEC Professional 380 (featuring PRO/VENIX)

In computing the DEC PDP-11 is something of a geologic feature. Plus, as most systems in the family were minicomputers, they had the whole monolith thing going for them too (minus murderous apes and sucking astronauts into hyperspace). Its fame is even more notable given that Digital Equipment Corporation was among the last major computer companies to introduce a 16-bit mini architecture, beaten by the IBM 1130 (1965), HP 2116A (1966), TI-960 (1969) and Data General Nova (1969) — itself a renegade offshoot of the "PDP-X" project which DEC president Ken Olsen didn't support and even cancelled in 1968 — leaving DEC to bring up the rear with the PDP-11/20 in 1970.

So it shouldn't be a surprise that DEC, admittedly like many fellow mini makers, was similarly retrograde when it officially entered the personal computer market in 1982. At least on paper the DEC Rainbow was reasonable enough: CP/M was still a thing and MS-DOS was just newly a thing, so Digital put an 8088 and a Z80 inside so it could run both. On the other hand, the DECmate II, ostensibly part of the venerable PDP-8 family, was mostly treated as a word processor and office machine; its operating system was somewhat crippled and various bugs hampered compatibility with earlier software. You could put a Z80 or an 8086 in it and run CP/M and MS-DOS (more or less), but it wasn't a PC, and its practical utility as a micro-PDP didn't fully match the promise.

However, what DEC did to the PDP-11 was odder still. The 1982 DEC Professional 350 had the same F-11 ("Fonz") CPU as the bigger PDP-11/23, though that's where the similarity ends, as it implemented a new bus with completely different option cards and an incompatible interrupt system making it all but impossible to run unmodified PDP-11 programs. It had really nice graphics for 1982, but instead of the usual choices its intended system software was the laughably named Professional Operating System, or P/OS — execrated for its sluggish menus and limited feature set, of which people were only too quick to make the obvious joke. You could get CPU option cards like the DECmate II's to also make it into a weak PC or a weak CP/M machine, but they ran through P/OS too, and they weren't cheap. At the same time, however, in order to be the most inexpensive PDP-11 system ever, the low-binned DEC Professional 325 didn't even have a hard disk.

All of these systems were originally meant as commodity machines for office work, yet more or less with the exception of the Rainbow, they couldn't run much that office professionals actually wanted to run and little that existing PDP users did. Still, despite questionable technical choices, these machines (the Pros in particular) are some of the most well-built computers of the era. Indeed, they must have sold in some quantity to justify the Pro getting another shot as a high end system. Here's the apex of the line, the 1984 DEC Professional 380.

The Pro 380 upgraded to the beefier J-11 ("Jaws") CPU from the PDP-11/73, running two to three times faster than the 325 and 350. It had faster RAM and came with more of it, and boasted quicker graphics with double the vertical resolution built right into the logic board. The 380 still has its faults, notably being two-thirds the speed of the 11/73 and having no cache, plus all of the 325/350's incompatibilities. Taken on its merits, though, it's a tank of a machine, a reasonably powerful workstation, and the most practical PDP-adjacent thing you can actually slap on a (large) desk.

This particular unit is one of the few artifacts I have left from a massive DEC haul almost twelve years ago. It runs PRO/VENIX, the only official DEC Unix option for the Pros, but in its less common final release (we'll talk about versions of Venix). I don't trust the clanky ST-506 hard drive anymore, so today we'll convert it to solid state and double its base RAM to make it even more professional, and then play around in VENIX some for a taste of old-school classic Unix — after, of course, some history.

The "35-cent" Commodore 64 softmodem

Rockwell famously used 6502-based cores in modems for many years, but that doesn't mean other 6502s couldn't be used. If only there were a way to connect a Commodore 64's audio output directly to an RJ-11 plug ...

Of the many interesting posts from Usenet's more golden days, one of my favourites was John Iannetta's "35-cent modem," where the SID chip provides one-way data modulation to a receiving modem connected via the C64's sound output. While I remember him posting it back in 1998, I never actually tried it at the time.

Wouldn't you know it, but it came to mind the other day when I was looking at a recent haul of Convergent WorkSlate stuff I've got to catalogue. Officially the WorkSlate's only means of telecommunications is its 300 baud internal modem. While we have a 9600bps way of wiring up a Workslate to a modern computer, it's always nice to have a simpler alternative, and I figured this would be a great challenge to see if John's old program could let my Commodore SX-64 talk to my WorkSlate. Spoiler alert: it works!

Refurb weekend: Atari Stacy

Ask any Atari Stacy owner how to open an Atari Stacy and the answer is always "never, if you can avoid it." So I'll just lead with this spoiler image after the refurb to prove this particular escapade didn't completely end in tragedy:

Stacys are horrible machines to work on. Nobody likes being inside of one. The daughterboards don't have keyed connectors (including the power supply!) and are constantly attempting to come free, the display "cable" is actually a Medusa's wig of wires that like to short (!), the top case is a huge bulky sheet of increasingly fragile plastic that somehow has to fit around the floppy drive yet down on the keyboard simultaneously, and the entire laptop is an uneasy sandwich held together by a small set of screws in plastic races that strip and fracture with little provocation. So why do we tolerate this very bad, bad, bad, bad girl? Because most of us will never see the much lighter and streamlined STBook in the flesh, let alone own one. If you really want a portable all-in-one Atari ST system, the Stacy is likely the best you're gonna do.

And we're going to make it worse, because this is the lowest-binned Stacy with the base 1MB of memory. I want to put the full 4MB the hardware supports in it to expand its operating system choices. It turns out that's much harder to do than I ever expected, making repairing its bad left mouse button while we're in there almost incidental — let's just say the process eventually involved cutting sheet metal. I'm not entirely happy with the end result but it's got 4MB, it's back together and it boots. Grit your teeth while we do a post-mortem on this really rough Refurb Weekend.

A mostly merry Southern Hemisphere Commodore Christmas

A merry Christmas and happy holidays from the Southern Hemisphere, where it's our year to be with my wife's family in regional New South Wales, Australia. One of my wife's relatives had an "old Commodore" in their house and asked if I wanted it. Stupid question, yeah?

So they brought over, in their original boxes, a Commodore 128D (PAL) with Commodore 1802 monitor, Commodore MPS-1250 dot matrix printer and a separate box of magazines, circulars and boxed software. Let's fire it up!

Composite and hard reset mods for the Tandyvision One

I still have my literal first home computer (the Tomy Tutor), and it so happens I also have my literal first game console: the Tandyvision One, Tandy Radio Shack's label variant of the Mattel Intellivision Master Component.

In another happy coincidence, my first console, like my first home computer, was also an early 16-bit system: in this case powered by the General Instrument CP1610, famous for its use of 10-bit "decle" instructions stored on specialized ROMs in Inty cartridges. This was a family system and did lots of two-player duty with my father and sisters. Although I still have nearly all of our old cartridges, even the manuals and controller overlays, nowadays I play with a Cuttle Cart 3 and an Intellivoice speech synthesizer module.

Like my original Tutor, this is one system I'd never part with, so if I were going to make some tweaks to it this would be the unit. We're going to do two mods in this article, neither particularly complex but nonetheless handy: composite video and sound outputs for improved quality and flexibility, and a power cycle hard reset button for convenience and less wear on the power switch. Some drilling and soldering required but not very much.

The Hall SC-VGA-2 video processor, the Atari ST and NeXTSTEP: more tales of the unscreenshotable

A periodic fascination on this blog is figuring out better ways to get better screenshots of our classic systems, which often hail from the Wild Wild West/East in terms of video standards (read all entries in this series). Naturally the best way is a bitwise direct grab of the framebuffer, but that's only possible if there's sufficient operating system support. This support is obviously absent for things like boot messages (especially important when investigating NetWare on the Power Mac 6100), so we need to figure out a way to capture that information. My capture box of choice is currently an Inogeni VGA2USB3, which is small, self-contained, USB-powered, highly compatible and makes high quality grabs of anything you can wire into composite or a VGA HD-15 connector up to 1080p, but is limited to 60Hz refresh rates. Various solutions like the OSSC exist, but these are more oriented to arcades and consoles rather than (our primary interest) workstations, and the Pro in particular isn't cheap.

While you might be able to trick the hardware into emitting a compatible signal, that's not good enough or even possible with several of my machines. Previously my problem child was astro, my SAIC Galaxy 1100, a modified PA-RISC HP 9000/712 crammed into a MIL-SPEC portable case with a fabulous built-in flat panel. These machines ran HP-UX 10.10 in their original heyday, but this particular system runs NeXTSTEP 3.3 for PA-RISC during the brief period of time NeXT supported the architecture and was a big hit at the Vintage Computer Festival West a few years ago. Its flat panel runs at an odd 62Hz and the external VGA port only generates a 60Hz signal for 640x480 (all other resolutions use different refresh rates), which is hopeless for running NeXTSTEP. However, now I have a new candidate I'd like to get some grabs off: a particularly problematic member of the Atari ST family which has been the subject of a long-running and highly frustrating extended Refurb Weekend. You'll get to meet this bad girl soon enough. The standard ST high resolution mode is 640x400 — at 71.2Hz. I can get a picture from it with my trusty NEC flat panel, but not with the Inogeni.

The usual solution to this is a scan converter, but those can be expensive and inconvenient. Here's one I picked up used on eBay for $2. Yes, really. It cost more to ship it.

This is the Hall Research Technologies SC-VGA-2, sold as a "VGA/HDTV Video Processor." In addition to slicing, dicing and pureeing, apparently, it will take any of a bundle of input formats and both rescale and resample them on the fly into the VGA or HDTV signal you desire, including 60Hz rates. This came from a seller specializing in teleprompter equipment and Hall still sells an HDMI version with additional resolutions ... for around US$500. However, this or the slightly newer SC-VGA-2A and SC-VGA-2B are all relatively common devices and found substantially cheaper used. Let's try it out and show some sample output, including those delicious NeXTSTEP system messages and some ST grabs.

One-parting some Commodore 64 utilities for fun and profit

I've got a few retrocomputing bucket list items I'm slowly working down, and a couple of them involve some little Commodore 64 games I've had kicking around on the backburner. However, every game needs media assets, and while there are many great tools for doing art on your present-day workstation and exporting it, sometimes you just want what you used to work with — in as convenient and quick-loading a way as possible that blends with modern emulation workflows. So here's two I tweaked and one-parted — Ultrafont+ and DOODLE! — and some tips for making self-contained tools like these yourself.