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TI 99/4a

bifo86

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If you didn't know better you might think the design of the 99/4A was the result of a drunken bar bet over making the most inefficient small computer design humanly possible. Somebody definitely held someone else's beer at some point.

70s industrial design: never attribute to incompetence what can be explained by bureaucracy. Source all of your parts internally from different departments with different priorities. The PC and the Apple 2 (and later Mac) worked because each was created by a small team using off the shelf parts. C64, Atari 8-bit range and the Mac later stumbled badly later when the team size ballooned combined with a closed system architecture, while the Amiga worked well with the small team approach and then, again, followed the same path.
 

Juror22

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Wow - I cannot believe the negativity on this part of the forum. Did they give the TI a subcategory just to give it a beat down?

I had one when they first came out (I basically got it for free, when they were closing them out, it was all that I could afford at the time and I did my first programming on that box). A few years ago, I answered a CL ad for a free TI99/4A in a nearby town. It came with dozens of carts, books, and the Peripheral Expansion box. About all that I have done so far is to hook it up to a monitor and run a short BASIC program, but when I have the time, I'll work with the assembler (one of the books/software packages I got with it).

I have a lot of other computers that I collect (PC's, DEC, Mac, HP, Sun, IBM AIX, Tandy, etc) and like everyone else, my phone outperforms almost anything listed in these forums, but that is not really why any of us collect, restore and use these machines, is it?
 

commodorejohn

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It's not that it underperformed modern computers, or even that it underperformed contemporary computers. It's that it should've been so much better than it was, but instead it was deliberately hampered beyond any amount of reasonable explanation.
 

Eudimorphodon

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Wow - I cannot believe the negativity on this part of the forum. Did they give the TI a subcategory just to give it a beat down?

For some of the people that love these machines talking about all the boneheaded things that went into them and how to work around them is part of the fun. And make no mistake, whether you love them or hate them there were a lot of boneheaded decisions, both technical and business, that went into the TI 99/4a. ;)

That said, having the PEB and additional RAM at least *partially* solves the worst problem of the base TI 99/4a, which is it quite literally has only 256 *bytes* of real RAM directly accessible to the CPU at its full bus width. (Every other scrap of memory in the machine requires *many* machine cycles' worth of indirection to access and by design cannot hold machine code.)
 

ngtwolf

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Wow - I cannot believe the negativity on this part of the forum. Did they give the TI a subcategory just to give it a beat down?

There are a lot of negatives of the TI 99/4A, but trust me, the hate this thing is getting is nothing compared to the hate most retro computer folks have for the Timex Sinclair 1000. With the TI-99 it's more a matter of disappointment at something that could/should have been better, but at least we've bothered to try them to learn their positives and negatives. The Timex was all negatives and for most of us, it just sits on a shelf as an oddity, not even worth the effort to get it running or use. The TI-99 was something people actually wanted but as mentioned, due to many bureaucratic decisions, failed. The timex was nothing that anyone wanted, it was the result of kids asking for a computer and parents saying 'well, this says it's a computer and it's only $50'. There was a time back in the day where the TI99 was also $50, and I think all of us, if given the choice between the two, would pick the TI99.
 

Juror22

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I'm sorry if I misread the vibe - I do agree for the most part that there is not a lot to do with it, especially today, but I could not afford thousands, or even hundreds of dollars for a computer, back when I got mine and it was able to provide me with an inexpensive introduction to games, programming and computers in general.

There was a time back in the day where the TI99 was also $50, and I think all of us, if given the choice between the two, would pick the TI99.
I bought mine for $50 and it had a $49 rebate. So it ended up costing me almost nothing, but tax. Back then, I bought a used PEB from another kid, a little older than I was and that did cost a bit, but I remember copying files to the disk drive and loading them back and that it was almost magical at the time.
 

Gary C

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There are a lot of negatives of the TI 99/4A, but trust me, the hate this thing is getting is nothing compared to the hate most retro computer folks have for the Timex Sinclair 1000. With the TI-99 it's more a matter of disappointment at something that could/should have been better, but at least we've bothered to try them to learn their positives and negatives. The Timex was all negatives and for most of us, it just sits on a shelf as an oddity, not even worth the effort to get it running or use. The TI-99 was something people actually wanted but as mentioned, due to many bureaucratic decisions, failed. The timex was nothing that anyone wanted, it was the result of kids asking for a computer and parents saying 'well, this says it's a computer and it's only $50'. There was a time back in the day where the TI99 was also $50, and I think all of us, if given the choice between the two, would pick the TI99.


Ees 'avin a go at the Sinclair now !

In the UK it was all we could get when it came out, and very glad I was for it, even with 1K

TI99/4a would have cost about £500 in 1981 in the UK or £69 for the ZX.
 
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Gary C

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I mean, say what you want about the TI-99/4a, at least it had an actual keyboard ;)

Yep.

Always wanted one as a kid, just been reading about the discounts on them that TI offered, unbelievable. Certainly never knew how low they went (I'm assuming that was in the US only ?) but by then I had a BBC (and a real keyboard)
 

Eudimorphodon

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Of course the irony of those rebates was TI was simply *shoveling* vast quantities of money into the furnace in order to compete with the most basic bottom-of-the-barrel computers on the market (VIC-20, Timex-Sinclair, etc) in some vague fever-dream hope that by selling enough of them they'd be able to make their money back on software and peripheral sales... on a machine that they intentionally made very difficult to expand and write software for in order to lock out third party developers. It was pure madness, especially given how all the weird design compromises of the 99/4A made it more expensive to manufacture than anything it was trying to poach market share from.
 

krebizfan

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The British counterpart to the TI-99/4A would be the Sinclair QL though many of the QL's problems were caused by compromises designed to make the QL into a portable system with built-in display and not adjusting the design when it no longer was going to be that. Every decision for both the TI-99 and QL seems reasonable but the cumulative effects of all the decisions resulted in a system difficult to sell at a profit.
 

ngtwolf

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Ees 'avin a go at the Sinclair now !

In the UK it was all we could get when it came out, and very glad I was for it, even with 1K

TI99/4a would have cost about £500 in 1981 in the UK or £69 for the ZX.

I guess I was unnecessarily harsh on the Sinclair as I can still use it to this day in my office:

IMG_20190822_115556.jpg

:)
 

vwestlife

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The TI-99/4 at least showed IBM how an industry giant should not make a 16-bit personal computer.

And remember that TI put Commodore out of the calculator business, so Commodore was all too happy to return the favor by doing everything they could to put TI out of the computer business.
 

Eudimorphodon

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Every decision for both the TI-99 and QL seems reasonable but the cumulative effects of all the decisions resulted in a system difficult to sell at a profit.

I dunno, the whole ROM/GROM/MPX memory and bus architecture of the 99/4A is just plain wack from pretty much any angle. If everything were equal then, sure, a 3Mhz 9900 verses a 1Mhz 6502 sounds like should have been a pretty easy win (but in fact is nowhere close to a slam dunk, since the 9900's instruction timings aren't particularly impressive and all the CPU "registers" reside in external RAM), but even if that were true designing the system so it essentially has to run everything under an interpreter completely negates any point of having the more expensive CPU in it. And compared to a "sane" shared memory system like an Apple II or VIC-20 the 99/4a is hideously over-complicated and needs more chips for worse performance. Having just the VDP RAM might make a vague amount of sense if it were just a game console, but trying to turn it into a computer (and not completing work on an apropos 8-bit version of the 9900) made it the most expensive ridiculously overengineered game console ever simply masquerading as a computer.

Compared to something like a Sinclair ZX-81 I can at least respect the ZX for coming by its limitations honestly; it's a Z-80 tied to the cheapest off the shelf ROM and a RAM chips they could get away with and held together with some very clever software; it's not really a practical design for a "real" computer but as an exercise in minimalism it's actually pretty amazing and it *did* get a starter computer into the hands of a lot of people while still actually being profitable to churn out. (Not much profit, mind you, but you could still sell it for a few bucks more than it cost in parts.) The TI was intentionally crippled at great cost and TI just kept doubling down on bad decisions until it broke the company. Which makes it a fascinating artifact of history, at least?
 

krebizfan

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Part of the design for the TI-99/4A was to use the 9900 with some emulation layers to simulate a planned but never built low cost variant of the 9900. Made sense for testing prototypes but the cost of materials required retail prices of about $600 to break even.

Take a look at the TMS 9995 which took the 9900 base design with an added 256 bytes of RAM on chip and made it fit in a standard 40 pin (cheap) package. Imagine the cost savings if the TI-99/4A had been using one of those chips instead of the complex 9900 plus scratchpad RAM design. With a little work, I think that could have resulted in a slightly faster TI-99 which could have been sold at $200 while making a profit. Still a strange computer and not a great value but much improved compared to what TI tried.
 
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vwestlife

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Take a look at the TMS 9995 which took the 9900 base design with an added 256 bytes of RAM on chip and made it fit in a standard 40 pin (cheap) package.
That was the CPU used in three unreleased prototype computers: TI-99/2, a super cheap Timex-Sinclair competitor with a chiclet keyboard, black & white video, and no sound; the TI-99/5 (a.k.a. TI-99/4B), an updated version of the 99/4A with 48K RAM, built-in speech synthesizer, Hexbus interface, and RGB video output; and the TI-99/8, with 64K RAM and a better keyboard.

The TMS 9995 did end up in the Tomy Tutor, which was heavily based on the TI-99/4A but designed as a children's educational computer, released in 1982 in Japan and 1983 in the USA but a marketplace failure.
 
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