Recommend me book! TRS-80 & TI-99/4A

[Keatah]

Looking for some books & articles that discuss the architectures of both the TRS-80 & TI-99/4A.

 

As an Apple II aficionado, I'm thoroughly versed in why things were done they way they were done. The philosophy, the trade-offs, the innovations, the balance of features. The pressures of marketing vs engineering. Production vs beancounters. Including all the consumer's inputs and wishes. There's no shortage of materials and describing it all.

 

But for next month's sabbatical I wouldn't mind buffing up on the TRS-80 I, II, III, and the TI-99/4A.

Edited August 22, 2021 by Keatah

[1980gamer]

Sorry, no help to you.  But I would like to know this as well.

The first 2 computers I ever touched were the TI99/4A and the TRS-80 Model III  1981-82?

 

A friend of mine had a model 4P.  I wanted one so bad.  LOL.  By the time I could buy one, you couldn't anymore   but that worked out better for me.  I got a PC instead.

 

Edited August 23, 2021 by 1980gamer
typo

[Hwlngmad]

17 hours ago, Keatah said:

Looking for some books & articles that discuss the architectures of both the TRS-80 & TI-99/4A.

 

As an Apple II aficionado, I'm thoroughly versed in why things were done they way they were done. The philosophy, the trade-offs, the innovations, the balance of features. The pressures of marketing vs engineering. Production vs beancounters. Including all the consumer's inputs and wishes. There's no shortage of materials and describing it all.

 

But for next month's sabbatical I wouldn't mind buffing up on the TRS-80 I, II, III, and the TI-99/4A.

If you want books on Tandy, read Priming the Pump (https://www.amazon.com/Priming-Pump-TRS-80-Enthusiasts-Revolution/dp/0979346800/ref=sr_1_1?dchild=1&keywords=priming+the+pump+book&qid=1629725741&sr=8-1) and CoCo: The Colorful History of Tandy's Underdog Computer (https://www.amazon.com/CoCo-Colorful-History-Underdog-Computer/dp/1138412953/ref=sr_1_1?crid=13QJB2AFO4L2U&dchild=1&keywords=bill+loguidice&qid=1629725767&sprefix=bill+logu%2Caps%2C181&sr=8-1).  I highly recommend both.

[wierd_w]

For the 4A, you should check out the treasure-trove of scanned documents on whtech. 

 

While not exactly books in the scope you are asking, they are the kind that actually matter.  White papers, technical documents, et al.

 

 

 

It is my understanding that the 4A has a hobbled 16 bit CPU, because they had logistical issues developing both the 4A and the TMS9900 CPU at the same time, and they had developer hell happen.  So, they saddled it behind an 8bit multiplexer, and had what is effectively an 8 bit computer, with a 16 bit processor (and a small tag of 16 bit accessible RAM, the "scratch pad").  The majority of the system memory is actually handled by the TMS9918A VDP, and is handled in 8 bit chunks through the multiplexer.  As a result of these design decisions, there are considerable waitstates and latency between memory accesses, which hobbles the system quite a lot.  TI also instituted a unique form of serial rom, called GROM. This is single byte indexed, with an internal (to the chip) location counter, which automatically increments itself on access. The system ROMs, and many cartridges, make use of this technology.  Since it was proprietary to TI, TI used it as a form of content control in later iterations of the computer (to basically shut out AtariSoft and pals).

 

 

Edited August 24, 2021 by wierd_w

[Keatah]

Sounds like a really wacky way of doing things. Serial ROM for OS and game cartridges? GPU handling system memory? Not to say that Apple's bit-mapped modes were any easier to grasp outside of slow-ass Applesoft BASIC. Seems to be no end to the convoluted creativity in those halcyon days.

 

But I get the feeling that TI was too cost conscious and didn't take enough risks with their Home Computer.

 

Apple II was simple for a kid to grasp. HPLOT X,Y to put a dot there. Or HPLOT A,B to X,Y to draw a line. Easy as pie!

 

But. Yes. That's the sort of reading I'm interested in at this moment. Theory of ops type stuff. System architecture notes and technical & business decisions.

 

If anyone had "Priming the Pump" and "They Create Worlds" in PDF I'd love to put them on my ipad!

[Krebizfan]

The problem for TI was not that they were cost conscious; it was the exact opposite. They chose to drop a low cost feature filled design using a Z-80 and use the much more expensive 9900 while waiting for a low cost 9900 variant to be produced. Texas Monthly's Apr 1984 article "Death of a Computer" is a historical overview of how the 99/4A changed and became more a chance to sell TI chips to other parts of TI than a working computer that could be sold for a profit. 

Edited August 24, 2021 by Krebizfan

[MarkO]

For the Tandy Color Computer, ( CoCo ),"CoCo: The Colorful History of Tandy's Underdog Computer" is pretty good, also there is "Tandy's Little Wonder, The Color Computer" you can get the PDF here:

https://archive.org/details/Tandys_Little_Wonder_1993_Farna_Systems

 

and the Second Edition is here:

https://colorcomputerarchive.com/repo/Documents/Books/Tandy's Little Wonder Second Edition (Farna Systems).pdf

 

 

 

MarkO

( Apple ][ user since JAN-1982, Tandy CoCo user since 2012 )