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Where did the "4" come from in 99/4A?


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#1 matthew180 OFFLINE  

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Posted Thu May 25, 2017 12:10 PM

So I had a random thought yesterday.  Where does the "4" come from in TI-99/4A?  I know:

 

TI = Texas Instruments

99 = reference to the TMS9900 CPU in the computer

4 = ?

A = reference to the 9918A VDP used in the "4A" to distinguish it from the "99/4" which used the 9918 (no "A") VDP.

 

I can't come up with anything for the "4"...  This has probably been discussed before, so obviously I did not do any searching before posting. ;-)

 



#2 Sinphaltimus OFFLINE  

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Posted Thu May 25, 2017 12:22 PM

Could it have something to do with the sound? 3 tones +1 noise?

#3 x24b OFFLINE  

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Posted Thu May 25, 2017 12:40 PM

Swingin' wild here, just 'cause...

 

Is it the 4th version of the Texas Instruments home computer? Was there a TI 99/1?

Perhaps it is a prototype/product naming system, like the Ford Model A, Windows 98, 409 cleanser, Heinz 57 steak sauce?



#4 digdugnate OFFLINE  

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Posted Thu May 25, 2017 1:24 PM

Swingin' wild here, just 'cause...

 

Is it the 4th version of the Texas Instruments home computer? Was there a TI 99/1?

Perhaps it is a prototype/product naming system, like the Ford Model A, Windows 98, 409 cleanser, Heinz 57 steak sauce?

i remember reading that there was a 99/2 that was being worked on, and the 99/8 had prototypes- maybe one of the engineers just liked even numbers, haha



#5 --- Ω --- OFFLINE  

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Posted Thu May 25, 2017 1:29 PM

Number of delays per instruction?



#6 RickyDean OFFLINE  

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Posted Thu May 25, 2017 1:32 PM

i remember reading that there was a 99/2 that was being worked on, and the 99/8 had prototypes- maybe one of the engineers just liked even numbers, haha

I think it was a version number. There was a 99/4 B and the 99/5 per Fabrices' site http://www.ti99.com/...9-4b-et-ti-99-5



#7 Odo OFFLINE  

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Posted Thu May 25, 2017 1:39 PM

My favorite history of the TI is a book called 'The Orphan Chronicles' and even it doesn't have an explanation for the 4. Perhaps because it was originally aimed at a price point of $400? If you haven't read it, there's a PDF scan at http://www.99er.net/...act=view&id=148

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#8 Airshack OFFLINE  

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Posted Thu May 25, 2017 1:51 PM

Number of delays per instruction?


Actual performance equals the performance of a TMS9900 16-bit processor divided by four.


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#9 Airshack OFFLINE  

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Posted Thu May 25, 2017 1:52 PM

Number of delays per instruction?


It had 99 problems but four decades later you'll still love it.


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#10 AwkwardPotato OFFLINE  

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Posted Thu May 25, 2017 3:12 PM

The 4 was actually also used in the prototypes for the original 99/4 - see here:

 

http://www.computerh...catalog/X720.86

 

Not sure if it really helps - just putting it out there. The Dimension 4 did have a few features that were removed for the release of the 99/4 when they found out what the price would finally be, so the 4 might have something to do with those features and could've moved on in the 99/4, however with a lack of meaning.


Edited by AwkwardPotato, Thu May 25, 2017 3:22 PM.


#11 Airshack OFFLINE  

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Posted Thu May 25, 2017 3:45 PM

Do the TI faithful here on AtarAge include any of the original TI folks? Seems so little is available on the 99/4 historically; especially when compared to the other systems of the day.

Do any of you have contacts with the players mentioned in the Orphan Chronicles?


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#12 Ksarul OFFLINE  

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Posted Thu May 25, 2017 5:08 PM

I talked to Mike Bunyard pretty regularly until a couple of years ago, and I still talk a lot with Blaine Crandall.

 

Based on the original name: the Dimension 4, I would suppose the name just morphed into the 99/4 when (for whatever reason) they moved away from the Dimension 4 name.  I guess they were planning on taking computing to the fourth dimension. . .



#13 Casey OFFLINE  

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Posted Thu May 25, 2017 5:10 PM

It follows the naming convention TI used for its minicomputers of the era.  The TI 990/4, /5, /9, /10, /10A, and /12 were all different models of the 990 series.  It makes sense that they would carry that naming convention to the home computer.  It still doesn't explain what the 4 means, but at least it explains where the name may have came from.



#14 1980gamer OFFLINE  

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Posted Thu May 25, 2017 6:48 PM

4 sprites per line...  

 

Guess not.



#15 Retrospect OFFLINE  

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Posted Thu May 25, 2017 11:23 PM

The prototype was named "Texas Instruments Dimension-4" meaning a 4th dimension.  Then it was renamed to go along with familiar TI naming conventions, and given the 99/4 name.  Then the new one came out with a TMS9918a video chip and the A came into it. 



#16 apersson850 OFFLINE  

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Posted Fri May 26, 2017 3:01 AM

It follows the naming convention TI used for its minicomputers of the era.  The TI 990/4, /5, /9, /10, /10A, and /12 were all different models of the 990 series.

 

Exactly. There you have the principle used by TI at that time. As this is a microcomputer, not a mini, removing one zero, thus making this the TI 99 instead of the TI 990, makes sense.

Then the different models in the TI 990 series had different numbers, indicating their capacity. The TI 990/9 was the original model. The TI 990/4 and TI 990/5 had the TMS 9900 CPU inside. The model 5 just had some more memory.

Thus making the new home computer the TI 99/4 made sense. Later there were smaller models (e.g. the TI 99/2) and larger models (e.g. TI 99/8) planned and developed.

Adding the A to the type designation is just what TI did when they made a revision of something with about the same capability. The TI 990/10 and the TI 990/10A are both at roughly the same level, but the TI 990/10A was modernized with a new set of chips, based on the TMS 99105 CPU.

On a similar level, the TI 99/4 and the TI 99/4A are of similar capacity, or at least equal enough not to motivate a model name change to TI 99/5. So they added the A, as they always did, and came up with the TI 99/4A. It would have been the same even if the TMS 9918A chip would have been called TMS 99182 instead, or whatever.



#17 sometimes99er OFFLINE  

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Posted Fri May 26, 2017 5:19 AM

4x TMS99xx = TMS9900 + TMS9901 + TMS9918 + TMS9919

#18 apersson850 OFFLINE  

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Posted Fri May 26, 2017 6:17 AM

Several of the posts here are pretty humoristic, for sure, but this is not the reason. Renaming the TMS 9919 to SN 76489 didn't change the name of the computer either.  :)



#19 AwkwardPotato OFFLINE  

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Posted Fri May 26, 2017 8:27 AM

So it's likely that the 4 was carried over from the name "Dimension 4" (a fourth dimension), and became the model number for the original 99/4 to follow TI's conventions, and other model numbers were derived from the computer's capability relative to the 99/4 (for example, 99/8 is around twice as powerful as the 99/4, etc)?


Edited by AwkwardPotato, Fri May 26, 2017 8:30 AM.


#20 arcadeshopper ONLINE  

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Posted Fri May 26, 2017 10:28 AM

Since there are two other computers with dimension in their name good they changed it..



#21 Willsy OFFLINE  

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Posted Fri May 26, 2017 4:40 PM

Number of delays per instruction?

 

I read that as number of days per instruction and laughed out loud!



#22 LASooner OFFLINE  

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Posted Fri May 26, 2017 8:15 PM

I talked to Mike Bunyard pretty regularly until a couple of years ago, and I still talk a lot with Blaine Crandall.

 

Based on the original name: the Dimension 4, I would suppose the name just morphed into the 99/4 when (for whatever reason) they moved away from the Dimension 4 name.  I guess they were planning on taking computing to the fourth dimension. . .

 

If the 4th dimension is time, it's certainly has been good at taking up a lot of that.



#23 Retrospect OFFLINE  

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Posted Sun May 28, 2017 3:07 PM

I think from what I've seen and read , this "4th dimension" was going to be the infra-red capability.  That was scrapped and then they just called it the TI-99/4

Hell why did they scrap that?  For 78/79 it was very futuristic stuff.  I can just see it now though it would have been like the Nintendo Switch you'd have had to have been sat straight in front of it for it to pick up! :)



#24 etownandy OFFLINE  

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Posted Tue May 30, 2017 2:31 PM

I haven't been able to verify all of the sources, but the Wikipedia article on the 4A (which REALLY could stand some expansion) suggests that "4" was a naming convention used as the lower end of the 990 mini line (990/4).  It also suggests the "A" came from similar naming conventions and not from the VDP, but every article on the subject I read back in the heyday claimed the "A" was from the 9918A.



#25 apersson850 OFFLINE  

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Posted Tue May 30, 2017 3:31 PM

That's just because those who wrote them didn't know about the mini computer series. It's as simple as the fact that TI used to put an "A" Bafter the first remake of a product, a "B" after the next revision and so on. Both the computer and the VDP got an update, so they both got an "A". It's just a coincidence that they both got an "A" at the same tme.

Look at the TI 990/10 for example. There's a TI 990/10A too, but just because they went from multi-chip CPU to the TMS 99105. No "A" in any chip there.

 

The TI 990/4 uses a TMS 9900 CPU and has 56 K RAM, to start with, so it's in about the same level as the TI 99/4 and 99/4A. Thus selecting /4 makes sense, and gives room for both more powerful (TI 99/8) and cheaper (TI 99/2) models.






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