RC2017/04 – April 20

Right after the last post, I came down sick.  Now I have to pick it up and get it together.

As of my last post I hadn’t even decided what to do for a game. Two games that I played in the past, came to mind.  I played Hammurabi on the PDP 11/70.  Star Merchant was another game I came across.  Both have possibilities, and apparently Creative Computing agreed about Hammurabi, because they published Dukedom, which was supposed to be a multiplayer version, although I never quite got it to work that way.

That leaves my with Star Merchant.  This would have been my first choice anyway, but I was concerned it might be to complicated to the short amount of time to work with.  Dukedom and Star Merchant were both published in the book, Big Computer Games in 1984.

Star Merchant is a game where you as captain, take your starship in a trade route of your choice between ten different star systems.  At each star system you buy and sell cargo in the attempt to gain a profit.

The original single player version from Creative Computing has been typed in and can be run on my emulated PDP 11/70.  Once you are signed on you can run it by entering:



RC2017/04 – April 5

I spent the last few days working on what I call recipes. They are short documents explaining how to do things. In this case I set up recipes for logging in, logging out and getting around RSTS/E.

A final recipe is actually just a list of telnet clients that I have used.

RC2017/04 – April 1

For this RetroChallenge I plan to write a multiplayer game that will run on an emulated PDP 11/70.

The first computer I ever used or worked on was a PDP 11/70 in High School. The main operating system when I had access to it was RSTS/E. The version back then was V06B and later V06C. I have had a fascination with the system ever since. Over the years I have run emulations of the PDP 11/70 under SimH and recently under Ersatz-11. The closest version of RSTS/E I have been able to setup is V7.0-07, so that is the version I will use.

On past RetroChallenges, I have seen some that in addition to following along reading the blog posts, it would be interesting to get hands on as well.

With that in mind, I have set up separate accounts in my emulated system to store my work and make it available to play with as I go along. The emulated system can be reached with telnet at: puff dot mooo dot com at port 4000. Once you connect you can log in with the account number 17,4 and password of RC. I’ll post a recipe above shortly showing how to get around in RSTS/E.

TI 99/4A and Games

Since I now have a fairly complete working TI 99/4A, I wanted to play with it.  The strangest thing I found, was I didn’t have any memories of using this machine back in the 80’s.  I have four cartridges for it, which are Home Financial Decisions, Music Maker, Othello and Adventure.

I have no musical ability and Financial Decisions is not a game, which leaves the last two.

I fired up Othello and played that for a couple of hours while watching TV.  Playing on the easiest settings I managed to win both games, but it was no a walk away.  My Othello skills were quite rusty.

I few nights after I got my program recorders worked out, I started up the TI and put in the adventure cartridge.  After choosing 2 for Adventure I get a startup screen of:


Scott Adam's Adventure Splash Screen

Scott Adam’s Adventure Splash Screen

Once that was running, the game wanted me to load the data off the cassette tape, which I set up.  It tells you step by step to rewind the tape, stop and press play.

How did I not remember that when you load the data off the tape it sounds like a dialup connection?  It is also not very fast, taking a little over 2 minutes and 33 seconds.  That doesn’t seem bad until you listen to that noise for over 2 1/2 minutes

The resolution of the text on the TI is not nearly as fine as most modern users are familiar with.  “Forty characters per line using 24 lines” (40 characters in quotes) is not much to work with.  This can make the game a little less descriptive than more modern games of this type.

I made a video of loading this adventure to show what it was like.



PHP 2700 – Texas Instruments Program Recorder

My adventures with the Texas Instruments Program Recorder.

On September 4, I found a beautiful Texas Instruments Program Recorder on eBay and bought it from MAKBONE2012.  It was delivered on September 13 and the packaging was really well done.   I bought this one because the seller said it was tested and working.  I bought a new set of Duracell ‘C’ batteries, put them in along with a tape.  The simplest test I could think of was pushing the fast forward button, nothing.  I tried the rewind button and again nothing.

I contacted the seller and told them what happened, the response was very quick along the lines of; that’s weird, I’ll issue a refund.  I got the whole refund right away.  I asked what I should do with the recorder, toss it, was the reply.

I go back to eBay and find another one, which was also said to be tested and working.  I order on September 22, and it arrives very quickly in good shape.  I try my simple test with the new Duracell batteries.  Fast forward, click, nothing.  Rewind, click nothing.  Rats.

I go out and buy another set of ‘C’ batteries, this time Energizer.  Same test, same results.  I try them in the first recorder which I haven’t tossed yet and get the same results.

It seems unlikely that two tape machines that were tested and working before I got them would not work.  I’m looking them over, no visual signs of damage.  I do notice something I had not paid attention to.  On both machines, they had six buttons for controls, but they also had a slide switch on top.  One setting was Play/Record and the other was Pause.  Both were set to Pause.  I moved the switch to Play/Record and tested it.  The machine quietly starts to fast forward, I push stop and try a rewind, resulting in it quietly rewinding.

I grab the other set of batteries and put them in the first player, move that switch and away it goes.

Now for the hard part.  I had this first player from MAKBONE2012, that works.  I can’t keep it and the money, so I contact him through eBay, let him know what a dummy I am and issue a refund back to him.

Now I have two program recorders and in my searches, I found several people selling cables for using two recorders with the TI.  I ordered one, which came in right away and am now set up to use them both.

TI 99/4a: Cables and Tapes

At the end of August, I ordered a pack of cassettes and a cable for the tape player.  The cables and tapes came in the first week of September, looking good.

I pulled out my tape player and set up my TI.  When I got ready to hook up the tape player, I found the tape player I had does not have the correct speaker jack.

Rather than trying to find an adapter that may work, I will go online and find a TI Tape player designed for the TI 99/4A.


Terminal Emulation, Apple //c & Mac SE

In August, I decided to use my Apple //c and my Macintosh SE as terminals on my emulated PDP 11(Puff).  I wanted them to work as video terminals.

In the past, when accessing Puff, I would use a telnet program on one of my pc’s.  I went with a pretty vanilla kind of setup.  I configured all terminals as LA36, and all the telnet programs I used worked.

When setting up this latest generation of Puff, I configured it so it would use com1: and com2: as vt100 terminals.

Com1: is set up at 1200,8n1 and that is where my //c is connected using a null modem cable.  Com2:, meanwhile is setup at 9600, 8n1 and is connected with a null modem cable to my Macintosh SE.  Instead of using telnet software I use a communications program on both machines to connect to Puff.

This is very much like using a dialup connection, so the first program I tried on the //c was ZLink.  I got it to work by matching the 1200, 8n1 parameters.  Using the Open Apple T command to change emulation to VT100.  The only program I knew of that worked differently on a display terminal was VT50PY, so I ran that.  It worked as I remembered, displaying a running a systat.

For software on the Mac side, I ran Mac Terminal, again VT50PY runs well on it.

At the high school we had two VT52 terminals and later received two more display terminals that were, I believe, VT100 compatible.  I don’t remember much about them, except they were amber screened and made with a crisp metal edged case.

Inspired, partly by David Moisan’s 2012 Retrochallange project Hac-Man, I was thinking I would recreate an old game or two.  I wanted to work on a game that used the VT100 ‘s cursor control abilities.  In high school I worked on a game I called GALAXY which was loosely based on the star trek games of that time.  It was written to be played on a display terminal only, as it required the ability to use cursor control to keep a grid on the screen and update it during play.

I did some research and found several sites with VT100 codes, but was missing the key to how to use them.  Johnny Billquist and Dennis Boone from comp.os.rsts came back with the key answer to cursor control.  Printing an escape character with the high bit set chr$(27+128) followed by the open square bracket, the row, a semicolon, the column (fixed column from colon, 18-sep-16) and the letter H positions the cursor.

PRINT CHR$(155);”[“;NUM1$(ROW%);”;”;NUM1$(COL%);”H”;

The semicolon at the end is important as it keeps the cursor there.

I wrote a simple program to position the cursor at each corner of the screen and print something.  It didn’t work on either the //c or the Mac.

David Moisan said said in his blog (https://davidcmoisan.wordpress.com/2012/07/05/hac-man-retrochallenge/) he used tera term, an open source windows program, in VT100 emulation and it worked.  I ran my copy and used telnet to connect to Puff.  When I ran my test program, it worked as I wanted it to.

That being the case, maybe the programs I was running on the //c and Mac weren’t as VT100 compatible as needed.  I tried ZLink on the Mac SE and when I connected, ran my test program and it worked.  On the Apple //c, I found ProTerm worked with my test program.  VT50PY would not run properly under either ProTerm on the //c or ZLink on the Mac, which made sense since it was written for the VT50 series of terminals.

UPDATE:  After testing both ProTerm and ZLink on the Apple //c, I found neither handles the graphics characters well.  Zlink just displays regular characters and ProTerm does not do corners or intersections with line drawing. (02-SEP-16)


TI 99/4A and Video Cable

My second computer was a TI 99/4a that I bought new at a J. C. Penny for about $100 in the fall of 1983.

I had put it in storage, but could not seem to find it until about three weeks ago.  I was looking for a printer and found the TI instead.  Quite excited, I brought it home.  It turns out, I did not store two important cords with it; the video cord to hook it up to a display and the audio cord to save or load programs and data with a cassette player.

I quickly looked online for a source for these cables.  I found a video cable at 8 bit Classics (https://www.8bitclassics.com/) for a reasonable price and ordered it.  When it came in right away, I tried it out and the TI seems to work fine.  I wanted to make sure the TI worked, before I ordered the audio cable.

Since that proved to be true, I looked on eBay and found one for right around $10 with shipping.  Another $10 and a pack of c90 cassette tapes is on the way (also found on eBay).

So now the TI will have to wait another week or so, for the tapes and cable to come in.


Emulating the PDP 11

Years ago, I stumbled across an article about emulating the PDP 11 computer.  After doing a little more research I found a package of programs called SimH, which allowed you to emulate a number of computers.  Amongst these was an emulator program for the PDP 11 system.

RSTS/E stands for Resource Sharing, Time Sharing, Extended and systems that ran it quite often hand dial up connections.  Our high school had several.  The emulators I have found let you set up dial up connections using telnet.

I set up a simulation of the PDP 11/70 that I used in high school.  I could not find a version of RSTS/E that was close to V06 that I used in high school so I installed one of the later version of RSTS/E, 9.2, I believe, and patched it with the y2K patch to fix dates.  I ran that for years to play with occasionally.

I later found a version that was much closer, V7.0.07.  This I installed and patched with a Y2K patch.  Again I ran this version for years.

Since 2003 or 2004, I’ve been running these simulations, and one thing has been missing, the ability to print seamlessly just like a real 11/70.

In this time, I have looked at another emulator, Ersatz 11, from time to time.  It is a commercial emulator for businesses who need to retain their software, but replace their hardware.  They allow hobbyist use for smaller configurations, and that works for me.

Last fall, I bought a Rosewill PCI communications card for my PC.  It has two serial ports and one parallel port.  I bought it to replace a usb serial adapter that I used to move files back and forth between my PC and either my Apple //c or my Macintosh SE.

Recently, I was reading through the documentation of Ersatz and realized, that printing was something it does.  I decided to try it out.  I started setting it up and added a little something extra.

I set it up to assign both serial ports as terminals.  My apple //c is set up as KB1: and my Mac SE as KB2: using terminal emulation software on both machines.  I also setup to assign lp0: to the windows printer using OSPRINT:.