A - Console B - Speech Synthesizer C - Peripheral Expansion Box (PEB) D - Monitor
Texas Instruments Inc. started distributing the TI-99/4a Home Computer in 1979. Of all the other computers on the market at the time the TI-99/4a is the one that shined the brightest. Being ahead of its time it can still be compared to a modern Personal Computer (PCs). It still packs a punch with many identical capabilities, even some that have yet to be matched by modern machines.
Being command line driven, you had to now more about the machine to successfully operate it then a Graphical User Interface like Windows or the MAC. That is not to say the 99/4a is difficult to operate, quite the opposite! Its most impressive attribute was that the commands were easy to understand and memorize. For example,
The above BASIC (Beginners All-purpose Symbolic Instruction Code) program calls a subroutine that clears the screen. Easy, huh? The 100 and 110 are there for you to keep track of program lines. It is necessary because one line might branch to another and you would have to follow the logic of the program when debugging.
If you didn't want to type in line numbers you can use a command called, "NUMBER" (NUM for short). NUM automatically types the line number in for you and increments it by any value you specify. For this example I used 10.
If you hit enter without typing any characters on a line number it drops out of NUM mode and puts you back into command mode which is designated by a greater than sign.
To execute the program you would then type, "RUN". To display all or a portion of your program to the screen again you would use the "LIST" command. "LIST 200-220" tells the computer to display program lines 200-220. Using LIST by itself tells the computer to start at the very beginning of the program, displaying it to the screen. Again, very simple to understand.
While you're programming in BASIC with the TI-99/4a you're actually being prepared for another language called, "Machine Language". Machine language is based on 0's and 1's. The BASIC command CHAR in part is what does it.
The below program shows how you can redefine the appearance of the letter "A" which has an ASCII value of 65 to a box. The Hexidecimal string within quotation marks defines the new appeance after the subroutine is executed. Within the 8x8 grid below you can see what its final appeance will look like.
When designing graphics on the TI you would draw a grid of 8x8 boxes on a sheet of graph paper and fill each one in according to your graphic pattern, like I did above. Next you would find the corresponding hexidecimal number (0-9,A-F) in the table on the left whose binary pattern matches that of each nibble in each row of your design. (a nibble is four binary digits, there are two per row) Since there are 8 binary digits per row you need two hexidecimal digits to represent each row which will give you 16 total as seen in the string in the CALL CHAR subroutine.
I know quite a bit about this little machine because it was my first computer. I sold my original system in the mid 1980's and decided recently to get back into it. Even after ten years of being away from the 99/4a I still remembered its commands and how to program it.
Texas Instruments made their Disk Controller Card compatible with IBM so you can put either a 5.25" or 3.5" floppy drive in the PEB as long as they both spin at 300 RPM. Some people I know have made an IDE (Integrated Drive Equipment) interface for it. If you don't like IDE, try SCSI ! The machine is extremely versatile. It was 16 bit too. Based on the TMS9900 Microprocessor.
The TI-99/4a Home Computer is an excellent choice for the entry level programmer simply because its programming language isn't object oriented like Windows programming is. It will help one better understand structured programming and build a good foundation for more advanced programming concepts such as Object Oriented Programming (OOP).
When I first got into OOP, it was confusing to me and I was already a programmer. It was confusing to me only because the book I had on the subject was written by someone who wasn't traversed in proper teaching methods. I got another book whose author made things clearer because he used analogies.
Windows keeps so much of the computer's hardware hidden from the programmer these days they do not have to be technically inclined as much as in the pre Windows era. Given my level of awareness, I recognize this as part of a dumbing down process.
The 99/4a has a Speech Synthesizer ("B") that is capable of mimicking any voice with phonetic speech, even Ernie and Bert of Sesame Street. It can even sing. The voice you heard when this page loaded was the default voice.
There was also a system designed for the 99/4a so that it could recognize your voice called, “The Milton Bradley Expansion System” Imagine that!
Modern PCs take an average of 30 seconds from turn on to the point where the user can operate the machine. There was no wait with the TI, it was ready to use immediately after the power switch was turned on. Unlike a Windows machine, it didn’t crash either.
The 99/4a can use either a monitor or hook up to your television set. The sound capabilities were quite impressive with 3 channels and 5 octives. Very few people know of this machine because in 1984 Texas Instruments discontinued the 99/4a.
The 99/8 was supposed to take over where the 99/4a left off but Texas Instruments never put it into production. They only made a few prototypes, some of which survive until this day.
The 99/8 had all the 99/4a had and then some. Best of all, NO WINDOWS! The built in programming language was more robust then TI EXTENDED BASIC was for the 4a, they called it TI EXTENDED BASIC II. TI EXTENDED BASIC II had all the power of the original plus some concepts found in GWBASIC and BASICA for the IBM PC, like the commands LINE, PSET, and CIRCLE.
Because of its unique qualities this computer does not deserve to die and be forgotten, yet technology like it gets thrown in the dump and forgotten about every day by individuals like yourself. In 1981 the TI-99/4a was my first computer. I currently own two TI-99/4a's with Speech Synthesizers and Peripheral Expansion Boxes.
If modern people are as advanced as they have been led to believe then why do people throw knowledge in the dump rather then realize it? The behavior in question can only be attributed to mind control and conditioning. Who in their right mind would throw knowledge in the dump? Knowledge is freedom and must be realized if one is to have a future.