Retro - TechTinkering

A Quickstart Guide to Editing Paper Tape with the Symbolic Tape Editor on the DEC PDP-8

Tue, 16 Jun 2009 15:27:26 GMT

Before re-writable storage devices, such as tape drives, become popular for the DEC PDP-8, owners had to rely on paper tape. This was fine for loading programs on pre-punched tape, but left the problem of how to put new data onto punched tape and how to edit existing data. This could be done off-line, but a better way was to use DEC's Symbolic Editor. This made life much easier as it allowed you to interactively edit a tape in a buffer, check the alterations and then output a new tape. This editor was used for quite a few years by those wanting to edit Assembly or FORTRAN source code. What follows is a brief introduction to using this editor.

Book Review: Electronic Brains: Stories from the Dawn of the Computer Age by Mike Hally

Wed, 03 Jun 2009 12:40:11 GMT

Amazon

This is an interesting history of computer development around the world during the 1940s and 50s. The book grew out of a radio series on BBS Radio 4 and contains lots of original material gained from interviews in 2001 and 2004. It is very accessible as it focuses slightly more on the events and people involved than the technical details, although it has enough of the latter to show how the technology evolved.

Emulating a DEC PDP-8 with SimH

Tue, 26 May 2009 15:00:33 GMT

The DEC PDP-8 mini-computer was launched on 22 March 1965 and was a great success. It was fairly cheap for the day and could easily be expanded. What attracts me most to the PDP-8 is its simple design. I therefore decided to experiment with the SimH emulation of this machine, but found that the documentation wasn't always straightforward. This article intends to show how easy SimH is and how powerful it can be.

Connecting a Parallel Printer to a Modern Linux Machine Using a LogiLink USB to Parallel Cable, D-SUB 25pin

Wed, 06 May 2009 11:34:28 GMT

Amazon

I have a number of older printers that I would like to connect to my modern machine, but have been unable to do so because my computer doesn't have a parallel interface. After searching the internet for a review of a usb to parallel cable that works reliably with Linux, I pretty much drew a blank. I then decided to look on Amazon and just give one a go. Below is my brief review of the product that I found to work. I hope that it is of some help to others who are looking for a similar cable.

An Introduction to Corewar

Thu, 30 Apr 2009 13:03:07 GMT

I remember reading about Corewar roughly 20 years ago and thinking that I will have to have a go at that when I get the time. As often happens in life, things got in the way and I only recently managed to give it a go. I love the challenge of programming and the competitive aspect of this programming game really appeals to me. The object of the game is to write a battle program that will take over a virtual computer and kill the other battle programs running upon it. Since the game recently celebrated it's 25th birthday, I thought that I would write the following brief introduction to the game to whet peoples' appetite and encourage new interest.

The Smallest Communication Program in the World?

Thu, 23 Apr 2009 11:32:46 GMT

I was going through a backup of my dos machine, taken in 1998, and came across some source code which I haven't seen for a long time. It was great to see that old code, and I must set-up a machine so that I can run some of it again. In particular I came across an attempt at writing the world's smallest communication program for an x86 based PC running DOS. I used to love writing these sort of little programs to test different things. I know we get more done these days, but it was fun tinkering around at such a low-level. So here follows the program.

xAce - A Jupiter Ace Emulator for Unix (Patched to correct garbled display)

Thu, 12 Feb 2009 16:24:46 GMT

I love the idea of the Jupiter Ace and think that the choice of the forth programming language was perfect for such a low-spec machine. It is a real shame that forth wasn't chosen for more computers of the period, instead of their using basic. I have not found many emulators for this machine and only one that I could run natively under Linux. This did, however, need patching, as without it the screen wasn't displaying properly. I will show how to patch it in this short post.

Book Review: The Mythical Man-Month: Essays on Software Engineering by Frederick P. Brooks, Jr.

Mon, 26 Jan 2009 16:28:26 GMT

Amazon

This book, written in 1975, offers a fascinating insight into the software engineering process used at that time. The author draws from his experience as project manager for the IBM System/360 and OS/360, and in doing so also sheds light on how they were put together. The 1995 edition, reviewed here, is particularly good as it presents the same 1975 text with only typographical alterations, followed by a couple of extra essays and reflection on the previous essays after 20 years.

Bouncing Babies

Tue, 16 Dec 2008 11:02:51 GMT

Bouncing Babies is one of the first games I remember playing on an IBM PC Compatible. I recall looking at this funny game and thinking that it really was a strange concept. It was released as Shareware by Dave Baskin, but I believe that it is now Freeware.

My Top 10 Commodore 64 Demos

Mon, 24 Nov 2008 16:44:27 GMT

There are so many great demos for the Commodore 64 and the demo scene is still thriving. Surprisingly there are even new effects being created for this machine. I have spent many hours going through a huge amount of demos to compile this list and I know that some of the entries are controversial, but they are my personal favourites. There are plenty of demos that people will wonder why they have been left out. This is mainly because the demos in this list already contain most of what they offer and I wanted to show a broad range of styles and effects.

Beneath a Steel Sky, My Favourite Graphical Adventure Game

Thu, 13 Nov 2008 15:42:18 GMT

Beneath a Steel Sky was released for the PC in 1994 by Revolution Software. It was received well and has gone on to be considered a cult classic. It uses the Virtual Theatre engine which was first used in Lure of the Temptress and among other things allows the non-player characters to have a basic level of artificial intelligence.

Using ScummVM to Play Classic Adventure Games

Mon, 10 Nov 2008 11:13:16 GMT

ScummVM is Virtual Machine, that allows you to run adventure games created for a number of game creation engines. This is a great way of playing those classic adventure games that you loved so much, or never got a chance to play at the time. Some of them such as Beneath a Steel Sky have rarely been bettered and can provide hours of fun.

Writing My First Program To Toggle In To The IMSAI 8080

Wed, 05 Nov 2008 10:21:23 GMT

I have long been fascinated with entering programs into computers by methods not involving a standard keyboard and monitor. This interest was peeked by my last article: Using the latest z80pack‚ version 1.17‚ to emulate an Altair 8800 or IMSAI 8080 using the new graphical FrontPanel. I have therefore chosen to design and write a program for the IMSAI 8080. In this article I will show you how I went about it, and how you could do the same. You may want to look at this article, if you don't own an IMSAI 8080 and don't already have an emulator for it.

Using the latest z80pack, version 1.17, to emulate an Altair 8800 or IMSAI 8080 using the new graphical FrontPanel

Wed, 29 Oct 2008 04:13:54 GMT

Udo Munk has just released the latest version of his z80pack emulator, version 1.17, which now includes John Kichury's FrontPanel library. As well as being a superb emulator to run CP/M on, it now gives you a great graphical representation of the Altair 8800 and IMSAI 8080 with fully functional switches and flashing lights. If you've ever wondered what it would be like to use one of these machines, why not give it a try?

Using DOSBox to Run DOS Games and Applications

Fri, 24 Oct 2008 11:55:53 GMT

There were some brilliant games and applications released for DOS, and some of the games such as Command and Conquer are still very playable. There are a number of options to play these games today, from using a Virtual Machine such as QEMU, to DOSBox which is a dedicated DOS emulator. Both of these are included in most Linux distributions. I have chosen DOSBox as it is quick and very easy to use, you don't need to install a DOS compatible operating system on it, and it uses your native file system for storage.

Installing the HI-TECH Z80 C Compiler for CP/M

Wed, 22 Oct 2008 11:24:44 GMT

My language of choice is C and I am currently getting more involved with the CP/M operating system. I have therefore decided that it would be nice to have a C compiler working under CP/M. There are a number of options available in the archives, but I have found that HI-TECH are allowing their CP/M C compiler to be downloaded for free. This is a very good product, has good documentation, is almost ANSI C compliant and can be used for commercial and non-commercial use. This, therefore, is the one I have chosen.

Installing ZDE 1.6, a programmers editor for CP/M

Tue, 21 Oct 2008 10:39:21 GMT

To do any serious programming under CP/M, the first thing you need is a good programmers editor. There aren't many in the archives, but I have tried most of them and found ZDE to be the best. It is small, has lots of features, and uses Wordstar commands which are familiar to me and easy to learn.

Setting up z80pack to create an emulated CP/M system

Fri, 17 Oct 2008 06:22:45 GMT

I have decided to try out some old CP/M software, but need something to run it on. I could either do this on my Commodore 128 or through emulation. Unfortunately the 1571 disk drive for my Commodore is currently out of action, so that leaves me with emulation. I was going to use vice to emulate a C128, but have always found it a pain to get CP/M files onto .D64/71 disk images. After looking around for the best emulator to run CP/M on, I came up with either YAZE-AG or z80pack. z80pack seems to be better supported, has more documentation and is being actively developed, so that's the one I have chosen for this article.

PDP 8 in 'Three Days of the Condor'

Tue, 14 Oct 2008 01:08:49 GMT

I watched 'Three Days of the Condor' the other night and loved seeing what I believe is a Dec PDP 8/E being used. Also featured in connection with this machine was a DecWriter, paper tape reader and possibly a VT-52 video terminal.

The film revolves around a CIA researcher, Robert Redford, finding out about a secret section within the CIA, and their attempts to silence him.

Book Review: Fundamentals of Operating Systems by A.M. Lister - Second Edition

Tue, 07 Oct 2008 17:06:00 GMT

Amazon

It was fascinating to read this book from 1979 and see how operating system design was viewed then, compared to now. The biggest change being the shift in importance from batch processing to the interactive use of computers. Despite the advances since this book was written, it is surprising how many themes are just as relevant.

Is COBOL really understandable after 14 years?

Fri, 08 Aug 2008 15:36:00 GMT

COBOL has been in the news quite a lot recently and I have been reading that there are still huge amounts of COBOL code running and being written. This led me to wonder why this language was still being used. I therefore decided to look at a few sites about COBOL and see what they said was good about the language. The main benefits appeared to be that it is portable and self-documenting. Indeed, I often read about how COBOL programmers say that they can go to code written 10-15 years ago and still easily understand what is happening.