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Story on TI-99/4A community


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#26 JamesD OFFLINE  

JamesD

    Quadrunner

  • 6,874 posts

Posted Sat Feb 18, 2017 1:37 PM

I'm usually just a lurker here, but I chip in my 2 cents every now and then... like now.
I didn't have a TI as a kid and I only know a couple people that did, but the TI always intrigued me.
The 16 bit CPU, and what were good graphics capabilities for the time sounded like it should be a winner.

As an adult, I learned more about the 9900 CPU and why the machine left the market so soon.
The 9900 is basically an IC version of the processor TI was putting in mini-computers. 
TI should have done better on that basis alone.
But TI seemed to do everything they could to prevent programmers from accessing that power, largely due to internal politics, and poor decisions.
Trying to go head to head against the C64 on the basis of price was the final mistake. 

I mostly hang around here to learn more about programming the 9900, and to see how people modify the machine.
I'm still waiting for a hardware mod that lets the CPU access a full 64K of 16 bit RAM, and for a fully pipelined 9900 FPGA cpu (which would be many times faster).
It would be interesting to see what the machine could do if that power is ever fully unleashed.
I do own a TI now.  It looks like it was never taken out of the box.  
One of these days  I'll actually write some code for it.
 



#27 Lee Stewart OFFLINE  

Lee Stewart

    River Patroller

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  • Location:Silver Run, Maryland

Posted Sun Feb 19, 2017 12:34 AM

...

I'm still waiting for a hardware mod that lets the CPU access a full 64K of 16 bit RAM, ...

 

Anders Persson (apersson850) has done this with a console mod briefly described in some posts in this thread: internal console expansion system

 

You probably already know this, but there are a lot of memory-mapped devices in the TI-99/4A to which  7KiB of the addressable 64KiB is dedicated.  The rest is directly addressable ROM and RAM, with only 8KiB of system ROM and 256 bytes of RAM (scratchpad) on the 16-bit bus.  It is all 16-bit RAM/ROM, however—most only accessible on the 8-bit bus, which incurs wait states.

 

I believe Anders’ 64KiB RAM is software switchable to swap normal TI-99/4A operation with most to all 64KiB RAM on the 16-bit bus.

 

There is also a project on Main Byte (bottom of page) for putting the 32KiB expansion RAM on the 16-bit bus in the console.

 

...lee



#28 Sinphaltimus OFFLINE  

Sinphaltimus

    Stargunner

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  • Distracted at the Keyboard
  • Location:Poconos, PA

Posted Sun Feb 19, 2017 6:44 AM

You can certainly use any of my shots from post your pictures.

#29 JamesD OFFLINE  

JamesD

    Quadrunner

  • 6,874 posts

Posted Sun Feb 19, 2017 3:12 PM

 

Anders Persson (apersson850) has done this with a console mod briefly described in some posts in this thread: internal console expansion system

 

You probably already know this, but there are a lot of memory-mapped devices in the TI-99/4A to which  7KiB of the addressable 64KiB is dedicated.  The rest is directly addressable ROM and RAM, with only 8KiB of system ROM and 256 bytes of RAM (scratchpad) on the 16-bit bus.  It is all 16-bit RAM/ROM, however—most only accessible on the 8-bit bus, which incurs wait states.

 

I believe Anders’ 64KiB RAM is software switchable to swap normal TI-99/4A operation with most to all 64KiB RAM on the 16-bit bus.

 

There is also a project on Main Byte (bottom of page) for putting the 32KiB expansion RAM on the 16-bit bus in the console.

 

...lee

Photos of a rat's nest of wires isn't quite what I'm looking for, and 32K isn't 64K, but almost bought one of those.
 



#30 LASooner OFFLINE  

LASooner

    Star Raider

  • 83 posts

Posted Wed Feb 22, 2017 3:03 AM

Thanks for all the responses, everyone, and sorry for those I didn't get around to (this story is a bit of a "free time" thing I squeeze in around normal writing duties.) Anyway, I'm still looking for a few more shots of peoples' TI-99 setups. If anyone has some to send over or if you just want to give permission to use your shots from the "post your picture" topic I would love to be able to use them. Thanks.

 

 

EHTcB9w.jpg


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#31 etownandy OFFLINE  

etownandy

    Star Raider

  • 92 posts

Posted Wed Feb 22, 2017 7:49 AM

My parents bought us a 99/4A in summer 1983 when I was in second grade, with Hangman and a cassette recorder.  Dad liked TI's calculators, and the price had dropped enough to where he felt comfortable with the purchase.  Dad was disgusted when the rug got pulled from under us just a few months later.  But that lead us to the Lima User Group, where I was pretty active writing articles for the newsletter and helping with the MUG Conferences that got spawned in the early 90s.  I released some Fairware titles (DV Manager 80, Phantom of the Opera), and had a MUG review published in microPENDIUM magazine.  

 

Although there were a few years between "then" and "now" when I didn't have access to a machine, I've pretty much had one around for most of my life.






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