Originally published in the Lima newsletter February 1991

THE 99/4 HOME COMPUTER:
Description of an Antique

by Charles Good - Lima Ohio User Group


A SHORT HISTORY OF THE TI HOME COMPUTER
TI began shipping the 99/4 (copyright 1979 on the color bar title screen) in October 1979.  It cost $1150 bundled with a 13 inch color monitor (FORTUNE, December 3, 1979, p.54).  Initially you had to take the monitor and could not purchase the 99/4 separately, and most purchasers had to pay close to full price.  Bundling was necessary because the 99/4 console passed but TIs TV modulator initially failed to pass FCC lab tests for noninterference with radio and TV broadcast reception.  The modulator emitted too much RF radiation (BUSINESS WEEK, March 19, 1979, p.37).  However, at that time the FCC did not regulate RF radiation from computing devices not hooked directly to TVs.  So TI got around the FCC regulations by offering to the public a "complete package".  It wasn't until January 1, 1981 that the FCC began testing ALL computers likely to be used in a home environment for TV/radio broadcast interference (POPULAR COMPUTING, November 1981, p.6).  TI eventually came up with a TV mudulator that would pass FCC tests and on November 28, 1980 began selling the console and monitor separately.  The console's list price was $650 (BUSINESS WEEK, December 8, 1980, p.28).  This was in one respect was actually a price increase, because the separate prices of the console and monitor were $250 more than their previous bundled price.

TI never published any sales data for the 99/4, but an independent market research firm estimated that TI would sell 25000 between its introduction and the end of 1980 (FORTUNE, June 16, 1980, p.139).  During the summer of 1981 TI quietly introduced the 99/4A with a list price of $525. By the time production of the 99/4A ceased in late 1983 or early 1984 the store price for a brand new 99/4A was $50, and over 1 million, perhaps several million 99/4As had been sold.


SUMMARY OF DIFFERENCES BETWEEN THE 99/4 AND 99/4A.
The most obvious differences are the keyboard, the lack of lower case letters on the "4", and the "4"s EQUATION CALCULATOR.  Most "4"s have an earphone jack on the front for private listening, but mine doesn't.  I will discuss most of these obvious differences in detail.  Other differences are listed in an accompanying article by Mike Wright.  The 4A gets its "A" from the fact that it has a 9918A video processor, whereas the 99/4 has a 9918 video processor.  The 9918A has bit map mode, which is not found on the 9918 processor.  This means that any software that uses bit map mode will not run on the 99/4.  Other differences between the 99/4 and 99/4A (such as the "4"s lack of an XOP assembly directive) are referenced in the index of the Editor/Assembler manual (p.456) under the heading "Computer differences".

In general, all software written for the "4" will run on the 4A.  Some complicated routines on the 4A were required to achieve this compatibility.  The "4" has 256
bytes more free memory in TI BASIC than the 4A, so some BASIC software written on a "4" may not work on an unexpanded 4A.  Lots of assembly or GPL software written for the 4A will NOT work on the "4", and there is no easy way to upgrade a "4" to a 4A.  The Mini Memory module and its line by line assembler, and the E/A module and its editor and assembler work OK on the "4".  A partial list of "won't work on the 99/4" software includes TI-Writer, Multiplan, Funnelweb v4.x, the LINES program that comes with the Mini Memory module, all the Milton Bradley game modules that were created to accompany the MBX system, Word Invasion, Parsec, Story Machine, Alpiner, Dragon Mix, and Word Radar.  Most of these modules and the LINES program are probably incompatible because they use bit map mode.  There are probably other reasons for the incompatibility of Multiplan, TI-Writer, and Funnelweb.  Even the non-editor parts of Funnelweb won't work on the "4".  When you boot Funnelweb into the "4" using the extended basic module, the title screen shows blanks where there should be lower case letters. You can then go to Funnelweb's extended basic user list, but here the "4" locks up.  You can't boot any software from the XB user list.


THE KLUDGY 99/4 KEYBOARD
After playing around with my "4" for a couple of months, I am forced to agree with the statement made in an accompanying FORTUNE magazine article.  The 99/4 is a real dog, mainly because of its keyboard.

There are 41 "chicklet" style keys, each slightly contoured and shaped like a narrow rectangle.  The 4A keyboard has 48 keys.  Although each 99/4 key depresses
separately, the keys are not what experienced users would call "full travel" There is no tactile response, no click, before the keys suddenly bottom out at the end of their downward travel.  Non-alphanumeric keys include one (and only one) SHIFT, an ENTER, a SPACE bar, and a SPACE key immediately to the left of the "A" key.  Alpha keys always produce upper case letters, so the SHIFT key is not used as often as it is on the 99/4A.  There is are no ALPHA LOCK, FCTN, or CTRL keys on the "4".  The "4"s SPACE key and bar do exactly the same thing, leave a blank space.  I can see no reason at all for this space KEY, in addition to the normally positioned space bar.  There are ASCII characters built into the 99/4 console that are not implemented on its limited keyboard, yet there is this stupid extra space key.

Touch typing on the 99/4 is difficult.  The keys are spread apart the same distance as on the familiar 99/4A keyboard, so it is possible to get all your fingers at once onto the keys.  But the small vertical size of the keys and their lack of tactile feel makes touch typing difficult. The small size and minimal contour of the "4"s keys makes it difficult for a touch typist to find by feel and seat his or her fingers in the center of the desired keys as the fingers move blindly around the keyboard.  The fully contoured much larger keys of the 4A (larger because there is less space between keys) makes touch typing much easier.  A special problem to experienced touch typists is the lack of any key to the right of the "L".  This means there is no "home" key for the little finger of the right hand to touch, and this will drive most touch typists crazy.  Frequently, when I try to type on my "4" I end up accidently moving my fingers over one key to the left on the home key row so that all ten
fingers have something to touch.  My left hand pinky finger is then on the useless SPACE key instead of on the "A" where it should be.  Then I type rtow fevfw.  TI recognized this problem.  The only application software written for the 99/A that is likely to require touch typing, the Terminal Emulator II, has a keyboard overlay with a raised area creating a fake key for the right hand's little finger.

TI provided a series of overlays specifically for use with the 99/4 and not usable with the 4A.  Some overlays were packaged with the "4" and others were available with specific command modules.  Because of the narrow vertical size of each key there is enough room between rows of keys on the "4" to display a text prompt immediately above ANY key, not just above the numeric keys as is the case with the 4A.  The overlays have text prompts for special keypresses, and cover the entire "4" keyboard, with the keys sticking up through holes in the overlay.  Special keypress usually involve using the SHIFT key in combination with a letter key. One overlay packaged with the "4" shows the editing keys used in BASIC.  SHIFT/Q=quit.  SHIFT/W=begin. SHIFT/ESDX= arrows. SHIFT/R=redo.  SHIFT/T=erase. SHIFT/A=aid.  SHIFT/F=delete.  SHIFT/G=insert. SHIFT/Z=back.  SHIFT/C=clear.  SHIFT/V=proceed.  There is nothing intuitive about some of these keypresses (why not SHIFT/B instead of /Z for back), so the overlay is really needed.  Another overlay packaged with the "4" shows the split keyboard keys that can be used with some games to simulate the 8 positions of joysticks #1 and #2.  In addition to the overlays packaged with the computer, I have seen overlays designed for use with the following command modules: Terminal emulator I, Terminal emulator II, Video graphs (PHM3005), and Video Chess.  There may be other overlays I havn't seen.

One of the reasons I give the 99/4 my "real dog" rating is the uncontrollable multiple repeat of the keys on my "4"s keyboard.  This makes it almost impossible to do any useful typing, touch or hunt and peck, on my "4".  Autorepeat of all keys at rate of 12 characters per second after a 1 second delay is listed as a NEW feature of the 99/4A (99ER MAGAZINE, Vol 1 #2, July/August 1981, p.48).  Autorepeat is NOT described in TI literature as a feature of the "4".  On my "4" any of the keys are likely to repeat INSTANTLY.  When you depress a "4" key, the keypress registers in the memory of the computer at a point about 1/2 way down the travel of the key.  There is no tactile response that this has occured.  The only thing your finger feels during a keypress is the sudden stop when the key bottoms out.  If the key hovers in this "1/2 way down" region you get mmmultiiiplle displays of theee keeey on the scrrreennn.  Try as I might, I can't seem to avoid this.  My "4"s keyboard is very sensitive.  Other experienced 4A users who have tried my "4" all have the same problem.  Having to use backspace (SHIFT/S) and delete (SHIFT/F) after every 6-10 keystrokes gets old really fast.  It has been suggested to me that this problem may be related to the ageing of my "4".  The condition may not have existed when my "4" was built.  One collector of TI computer products told me, "I had a 99/4 that did that.  I got rid of it and replaced it with a 99/4 that still works fine."


ONLY UPPER CASE LETTERS
No keypress on the "4" keyboard will give ASCII codes 97-122, the lower case letters.  Everything you type is in upper case, and this means you only use the SHIFT key in routine typing to shift the numeric keys and display !@@#$%^&&*().   The 99/4 uses a 5x6 pixel grid to display upper case letters.  The 99/4A uses a 5x7 grid to display both upper case and lower case text.  If you load into the "4" BASIC software written on a 4A that includes lower case text, the program seems to work OK, but no lowercase letters are displayed on screen.


THE EQUATION CALCULATOR
When you PRESS ANY KEY TO CONTINUE from the color bar powerup screen of the "4", you get a menu with three choices.  Press 1 for TI BASIC, 2 for EQUATION CALCULATOR, 3 for TITLE OF COMMAND MODULE.

The EQUATION CALCULATOR is a way of using the "4" in mathematical calculations without having to write a BASIC program to do the calculations.  You can do simple arithmetic, and you can also use exponential numbers, PI, SQR, exponents, SIN, COS, TAN, and ATN in your calculations. Everything that can be done using EQUIATION CALCULATOR can also be done using a TI BASIC program, or directly from BASIC command mode.

The EQUATION CALCULATOR screen is divided into three sections.  The bottom section is where you do your calculating.  You can, for example, type in a simple calculation such as 1567+56.98-145+(12/98), press <enter>, and display the answer.  To do the same thing in BASIC command mode, you would have to type PRINT before you typed the numbers of the calculation.  A single calculation is limited to 28 characters (one line of text).

You can define variables such as LENGTH=60, press the up arrow, and have this variable stored in memory and permanently displayed in the upper third of the EQUATION CALCULATOR screen.  You can display up to 6 variable names and their current values on screen in this way and not have to worry about the display scrolling off the top of the screen.  You can do the same thing in BASIC command mode by pressing <enter> after typing LENGTH=60.  The value of LENGTH would be stored in the computer's memory, but it would only remain on screen until it scrolled off the top due to subsequent entrys.

You can also define an equation such as PERIMETER=2*LENGTH+2*WIDTH and store this equation in the middle part of the EQUATION CALCULATOR screen.  You can then define the values of the variables LENGTH and WIDTH, use the down arrow to bring the equation into the bottom work area of the EQUATION CALCULATOR screen, press <enter> and display the current value of PERIMETER.  You can then redefine LENGTH and/or WIDTH, and reuse the equation to calculate the new value of PERIMETER.  You can also store equations for repeated use in a BASIC program, although you cannot store such an equation in memory in BASIC command mode.  In command mode you would have to retype the equation each time.

 I don't think EQUATION CALCULATOR is very useful. Apparently TI didn't either, because they dropped it when the 4A was released.  From BASIC (a program or from command mode) you can do all the same things, and more.  The main limitation of EQUATION CALCULATOR is the 28 character size of a formula or chain calculation.  The most common routine calculating I do on my 99/4A is to balance my checkbook.  I enter BASIC command mode and type PRINT, followed by my initial bank balance, followed by all my subsequent withdrawals (as minus numbers) and deposits (as positive numbers).  Before I press <enter> to display my balance I can check the screen to see that all the numbers in the calculation are typed correctly and use INSERT or DELETE to correct mistakes.  Such a long chain calculation requires several lines on the screen to display all the digits before pressing <enter>.  TI BASIC command mode gives me 4 lines. EXTENDED BASIC command mode gives me 5 lines.  EQUATION CALCULATOR allows me only one line of digits.


CONCLUDING REMARKS
When it was released in 1979 the 99/4 was the only consumer device that could really be called a "Home Computer".  It was the first to utilize cartridge software. Its speech synthesis was, and still is, unequaled.  It was easy to use, easy to program in BASIC, and it was powerful. Its high price was probably the major reason for its initially limited sales.  Its rotten keyboard didn't help either.   I'm sure glad we now have the 99/4A.  The 4A is much superior to the "4".