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Aardvark Daily

New Zealand's longest-running online daily news and commentary publication, now in its 24th year. The opinion pieces presented here are not purported to be fact but reasonable effort is made to ensure accuracy.

Content copyright © 1995 - 2018 to Bruce Simpson (aka Aardvark), the logo was kindly created for Aardvark Daily by the folks at aardvark.co.uk



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Four decades later...

7 August 2017

I started playing around with computers about 40 years ago -- back in 1977.

Coincidentally, this was apparently the same time that Radio Shack released the TRS80 Model 1.

I did get myself a TRS80, but only after a year or two of experimenting with home-built machines based on a variety of different processors and all with an infinitesimally small amount of memory.

You can imagine the impression that a "store bought" computer with Z80 processor, 4K of RAM, BASIC in ROM and a fantastic 128x64 graphics capability made on a "keen as beans" geek like myself.

Of course it was a horrendously expensive bit of kit. I forget the exact price but I'm pretty sure it was well over a thousand 1979 NZ dollars and back then, that was a *lot* of money!

But it was still a snot-load cheaper than the Apple II -- and besides the Apple 2 was (in my eyes) crippled by its integer-only BASIC, while the TRS80 had floating point (woohoo!).

Like the few others who were dabbling in home computers at that stage, I'd spend endless hours typing in long BASIC listings, fixing the syntax errors caused by my inability to type properly and then trying to save a decent copy onto the flaky cassette tapes that were the machine's only backup store.

Although they were the most irritating and difficult to type in without error, the machine-code games, consisting almost entirely of DATA and POKE instructions were usually the best. Unlike my home-built systems, the TRS80 had a memory-mapped video display so you could actually do animations and create games that were vaguely recognisible as knock-offs of arcade classics of the era such as "Space Invaders".

The TRS80 was also highly hackable.

It was only a very short time before I added a new character generator ROM which contained true lower-case and I also did the piggy-back 16MB RAM upgrade, consisting of soldering DRAM chips onto the top of existing ones on the main PCB.

There was a real Ford vs Holden rivalry between the Apple II owners and the TRS80 owners back in the day. The Apple guys would show us their fantastic colour graphics and games, we'd ask them to calculate 1.567 times 32.755 using their BASIC, and they'd frown.

Looking inside the boxes it was clear that the Apple II was a very "clever" design. It did a lot more of its magic in software, while the TRS80 just used more silicon to achieve the same function.

Pretty soon I was programming at an assembler level and found the Z80 to be a fun chip to work with -- but many of its instructions were pretty slow compared to the 6502's RISC-like instruction-set. This showed clearly even for BASIC programmers. A 0 to 10,000 FOR loop on the Apple would run many times faster than the same loop on the TRS80 due to the slick implementation of BASIC and those super-fast 6502 instructions.

However, writing assembler for the 6502 was a lot harder (dare I say frustrating) when trying to work in conjunction with an existing OS or supervisor software. The problem was all down to the way that "Page 0" (the first 256 bytes of RAM) were used by the processor. By indexing to this first page of RAM, the 6502 could do some super-fast stuff but once that page was all used up for that purpose, you were pretty stuffed. What's more, the basic operating system almost always used up the majority of that memory which left the applications programmer scratching around with just a few bytes of this precious page 0 space at their disposal.

No such worries with the Z80. It had absolute, relative and indexed addressing modes (with auto increment/decrement) that could be used with any part of the 64K of address space.

I guess I've bored the pants off the non-geeks who have made it this far through today's column but I guess it's one of those things that if you've never experienced the rush we got from engaging with these very early "personal computers", you probably won't understand the nostalgia I'm feeling right now.

Way back in the late 1970s, I could see an era where every house had its own computer but what neither I, nor anyone else I spoke with could foresee, was the way that these computers would be integrated into personal, portable phones that delivered power and function far beyond anything that anyone could imagine at the time.

When you see so much change in just 40 years, it really makes you wonder what the world will be like in another 40 years. An empty,scorched wasteland -- or a wonderful place where technology urecognisable by those of us today, continues to make our lives easier and more productive?

You tell me.

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