Monthly Archives: August 2016

TI 99/4A and Video Cable

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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

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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 had 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:.

Last Update: 15-Aug-17 Fixed spelling error and added a comma.

Exposure to the PDP 11

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I started high school in the fall of 1976 at South Portland High School.

We had a PDP 11/70 running RSTS/E Vo6B on 256KW of memory with two RP04 hard drives.

My first year in high school, my algebra class assigned us to write basic programs, solving certain quadratic equations.  This was my first real exposure to computers.  Over the course of high school, I spent a great many hours working on that computer.

During the Summer after both my Junior and Senior years I worked for the school as a programmer/operator.  I handled the daily and weekly system backups as well as maintained systems programs with updates.  From a programming point of view I worked on data entry and analysis programs for the high school, school department and the police department.

RSTS/E V06 was written in assembler, however most of the commonly used system programs were written in Basic-Plus.  I believe it was in my Junior year, we got a version of Pascal from OMSI.  The computer also had COBOL for the business classes.

I wrote mostly in Basic-Plus, although I did take a class in Pascal and wrote some in that.  I wrote one small program in Cobol to read cards from the card reader and put them in a data file.