THE TI 99/8 COMPUTER  
              notes by  Charles Good 
               Lima Ohio User Group   
   We have all heard of the legendary never released 99/8
computer.  Probably the best published description of this
computer to date are found in the December 1984 issue of
MICROPENDIUM, where it is stated that the suggested retail
price of the 99/8 would have been about $600.  Photos of
this computer in the article show the nameplate "Texas
Instruments Computer 99/8" just above the left side of the
keyboard.  Several working 99/8s are known by me to be in
private hands, and I have seen some on display, but not
operating, at a couple of TI shows.  I have, however, until
recently never really been clear what this machine could do.
Certainly the best way to judge the capabilities of a
computer is to use it.  I have never had the opportunity
play with a 99/8, but I have done the next best thing. 

    I have obtained a copy of the "Final Draft" of the 99/8
user documentation "GETTING STARTED" (dated 8/30/83 with the
code number "0811P") and "PROGRAMMER'S GUIDE" (the p-System
part dated 8/22/83 and the rest dated 9/15/83; with the code
numbers "1511P, formally 2183L", "2117L", and "1248P").
These books give an excellent description of the
capabilities of the 99/8 computer and interesting insights
about the very very rare Hexbus Disk Drive/Controller
peripheral.  I know of no working examples of the Hexbus
Disk Drive/Controller peripheral.  Sources tell me that it
was made for TI in Germany by Mechatronics.  In my opinion,
after reading these books, the greatest shortcomings of the
99/8 are the lack of an 80 column display and the inability
to generate unlimited speech using its internal speech
capabilities coupled with the TEII module. 

    In order to inform the TI community about "what might
have been if TI had only....." I am publishing the following
selected material all quoted from my 99/8 user
documentation.  Text below in brackets {} are my own words
interjected among these quotes. 
    "Features of the Texas Instruments Computer 99/8: 
     "KEYBOARD--The 99/8 computer has a full size, easy to
use 54 key keyboard. 
    "DISPLAY--The 99/8 displays program lines in a 24 row,
40 column format (text mode) using a handsome character set
with true lower case letters. 
    "SOUND AND SPEECH--The 99/8 can generate sound from 110
cycles per second to beyond the highest range of human
hearing.  Built-in SOLID STATE SPEECH synthesis reproduces
human speech electronically, accurately, and realistically. 
    "MEMORY--The 99/8 has 220 kilobytes of built in ROM.  In
addition, the computer has 80 kilobytes of RAM (64K of CPU
RAM, 16K of VDP RAM), which eliminates the need for memory
expansion for most applications.  If you need more memory,
the 99/8 can access up to 15 megabytes (approximately 15
million bytes) of total random access memory. {CG note: One
99/8 owner I talked to has working TI 128K and 512K PE box
RAM cards specifically designed for use with the 99/8.} TI
Extended BASIc II, a versatile and powerful version of the
BASIC programming language, is resident in the computer
p-System, the Universal Operating System (both these names
are trademarks of SofTech Microsystems, Inc.), allows other
programming languages, such as UCSD Pascal and TI PILOT
(both on diskette, sold separately), to be used. 
    "JOYSTICKS--An outlet is provided for Wired Remote
    "EXPANDABILITY--The built in HEXBUS Interface enables
you to use the low cost HEX-BUS peripherals; outlets for
connecting a cassette recorder and future peripheral devices
are also included. {CG note: Apparently the Hexbus port was
to be the main expansion port, at least initially.  There is
a 50 pin expansion for "future devices" on the side of the
computer.  This 50 pin 99/8 port is NOT the same as the side
expansion port on 99/4A consoles.  Some current 99/8 owners
have a TI cable that connects between this 50 pin port and
the "fire hose" cable of the PE box.  This is the only
existing device I know of for the 50 pin expansion port.} 
     "TECHNOLOGY--The Computer 99/8 uses the 16 bit TMS9995
microprocessor for fast program execution. {This is the same
10+ MHz CPU used today in the Geneve.  The 9995 is also
found in TIs 99/2 computer.} 

    "When you turn the computer on, the master title screen
^^^^^^^^| | | | | | | | | | | | | | 
^^^^^^^^^^^^^^^^^^(TI BUG) 
^^^^^^^^^^^^^^TEXAS INSTRUMENTS 

^^^^^^^^| | | | | | | | | | | | | |  
^^^^^^^^(c)1983 TEXAS INSTRUMENTS 3.0 

"Press any key to proceed to the next screen.  This is the
main selection list or the main "menu". 
If you have a Solid State Cartridge plugged into the slot at
the top of the computer console, the name of that program
usually appears as selection D on this screen. 

    "TI Extended BASIC II--This option enables you to access
the programming language built into the Computer 99/8.  When
you select TI Extended BASIC II, the computer automatically
executes at full speed. 
    "SET SPEED--This option enables you to change the speed
at which the computer "runs" programs contained in certain
preprogrammed software packages.  When the computer is
turned on, it is automatically set to run at 99/4A speed.
If this option is selected, this screen will appear: 

    "To proceed to the next section, "A tour of the
keyboard," select TI Extended BASIC II by pressing the A
^62720 Bytes free 

    "[Illustration of stacked HEX-BUS peripherals] 
    "DISK DRIVE/CONTROLLER 5102-A HexBus peripheral that
uses 5 1/4 inch diskettes, finds files quickly, and allows
either sequential or random file access.  With its
double-sided, double density capabilities, the Disk
Drive/Controller can store up to 320K of information on one
    "Disk Drive 5202--Up to three additional disk drives can
be used with the Disk Drive/Controller {CG note: up to a
total of 4 DSDD drives.  Since the Hexbus has only 4 data
lines data transfer is in nibbles rather than bytes.  I
suspect that the data transfer rate between Hexbus Disk
Drive/Controller and the 99/8 or other computer would be
significantly SLOWER than that obtained with the TI disk
controller and a 99/4A.} 

    "DATA TYPES--TI Extended BASIC II allows both integer
and real data types for numeric variables.  Because the
integer data type uses less storage space and requires less
processing time, using this data type when applicable (for
example, with FOR NEXT loops) facilitates faster program
execution.  To be stored as an integer a number must be a
whole number within the range -32768 to 32767. 

    "SIX DIFFERENT GRAPHIC MODES--These are accessed using
CALL GRAPHICS(x).  A wide variety of display techniques and
applications, including dividing graphics and text, are
available with the six graphics modes: 
    "PATTERN MODE--The default mode when using TI Extended
BASIC II is selected.  Characters are in 24 rows and 32
columns with each character defined by an 8x8 pixel
    "TEXT MODE--Characters are in 24 rows and 40 columns,
with each character defined by an 8x6 pixel configuration. 
    "SPLIT SCREEN MODE: TEXT HIGH--The screen is split into
two portions: the text portion (the top one third of the
screen) and a graphics portion.  Text is 8 rows by 32
columns; the graphics portion is 128 pixels by 256 pixels. 
    "SPLIT SCREEN MODE: TEXT LOW-- The same as Split Screen:
Text High except that the text is at the bottom one third of
the screen, with graphics at the top. 
    "HIGH RESOLUTION MODE--A full screen graphics mode with
192x256 pixels. 
    "MULTICOLOR MODE--Rather than in characters or pixels,
the screen displays in blocks, with 48 x 64 blocks. 

    "Screen Margins--CALL MARGINS enables you to redefine
the screen margins and thus define a text "window" on the

   "FREESPACE(0) returns the amount of unused memory space. 
   "VALHEX returns the decimal (base 10) value of a
hexadecimal (base 16) number. 
   "TERMCHAR returns the key code of the key combination
(such as ENTER, PROC'D, BACK, BEGIN) that terminated the
last INPUT, LINPUT, or ACCEPT statement. 

code is a subset) assembly language subprograms may be
loaded and run.  The subprograms INIT, LOAD, LINK, PEEK,
PEEKV, and POKEV are used to access assembly language
subprograms.  Relocatable assembly language programs created
for TI BASIC will execute correctly, although NUMREF may
return an integer value instead of a floating point value.
In addition, a string reference error may occur with STRREF
because STRREF {in TI BASIC} only allows strings up to 255
characters.  All POKEs and PEEKs as used in previous BASICs
fail in TI Extended BASIC II.  The INIT subprogram with no
parameter allocates 8K bytes of memory for assembly language
subprograms.  If a parameter is specified, more or less (up
to 24366 bytes) may be allocated.  Examples: 
     CALL INIT allocates 8K bytes of memory space. 
     CALL INIT(200) allocates 200 bytes of memory space. 
     CALL INIT(0) releases all memory previously allocated. 

    "DISPLAY VARIABLE 80 FORMAT--Files in DV80 format,
created by the LIST command or a text editing or word
processing program, may be loaded with the OLD command.
{CG Note: Does this mean that you can just display DV80 on
screen, or can you OLD and RUN BASIC code created with a
word processor? I don't know.} 

    "KEY CHIRP--TI Extended BASIC II enables you to turn on
an audible "chirp" that sounds whenever a key is pressed.
Enter the following command to turn on the key chirp: CALL
LOAD(VALHEX("84BD"),1).  Enter the following command to turn
the key chirp off: CALL LOAD(VALHEX("84BD"),0). 

    "STRING LENGTH--BASIC II permits strings up to 4090
characters in length.  TI BASIC and TI Extended BASIC permit
stings of up to {only} 255 characters in length. 

    "RECORD LENGTH--TI Extended BASIC II allows diskette
data files created on the Drive/Controller to have VARIABLE
records with lengths up to 4090 bytes.  TI BASIC and TI
Extended BASIC allow VARIABLE records to be only 254 bytes
long.  Diskette data files with FIXED length records are
limited to 255 bytes {same as TI BASIC}.  TI Extended BASIC
II allows cassette data files to have FIXED length records
up to 4032 bytes.  TI BASIC and TI Extended BASIC limit
cassette data files to 192 bytes or less.    
     "SOFTWARE CARTRIDGES--CALL to routines contained in a
plug in cartridge are not accessible in TI Extended BASIC
II.  Thus, programs that use the Personal Record Keeping
cartridge will not execute properly.  Text to Speech cannot
be accessed from TI Extended BASIC II with the Terminal
Emulator II cartridge.  Otherwise the Terminal Emulator II
cartridge functions normally. 
     "RESERVED WORDS--The following reserved words are
additions to the TI Extended BASIC reserved word list:
DCOLOR--These are graphics subprograms which enable you to
plot graphics and add color to them on the screen {in
graphics mode and in the graphics portion of a split
screen}.  CALL DRAW and CALL DRAWTO draw or erase lines
between specified pixels, thus making elaborate figures or
drawings possible. (The screen is comprised of a grid of
256x192 individual pixels.) CALL FILL colors the area
surrounding a specified pixel.  CALL DCOLOR sets the
graphics colors that are used by CALL DRAW, CALL DRAWTO,
     "Some HexBus peripherals can be accessed by using the
general format for file specification described earlier.
{This is the method we are all familiar with in BASIC file
access with the 99/4A.) Hexbus peripherals that may be
accessed with this alternate method of addressing are the
Disk Drive/Controller, the RS232, and the HexBus Modem. 
Alternate Device name| Hexbus Number 
DSK1.................| 101 
DSK2.................| 102 
DSK3.................| 103 
DSK4.................| 104 
RS232................|  20 
     "HEXBUS SUBCOMMANDS--The CA (catalog) command cannot be
used with the Hexbus Disk Drive/Controller peripheral. {CG
note: CA is supposed to generate a catalog of programs
stored by the 99/8 on a wafertape.  On my 99/2 computer CA
does generate a catalog of files on a Wafertape or
Mechatronic Quickdisk, and is supposed to work similarly
with TI's never released Hexbus Interface for the 99/4A.} 
     "The available characters {ASCII 0-255} and character
sets {32 character sets numbered 0-31} in Pattern Mode are
     "The p-System: 
    "The P-code interpreter, which is built into your
computer, enables you to execute existing p-System programs.
To develop your own programs you must have a TI disk system
(sold separately).  Also necessary are some or all of the
following TI products (sold separately): 
     1. p-System Editor/Filer/Utilities. 
     2. UCSD Pascal Compiler. 
     3. p-System Assembler/Linker. 
     "Note: These products are designed specifically for use
with the 99/8.  Software designed for use with the TI 99/4A
Home Computer may not work when used with the 99/8. 
     "With the p-System you can execute high-level language
programs such as UCSD Pascal and TI PILOT.  UCSD Pascal is
compiled and TI PILOT is interpreted to an intermediate
language called "P-code" or "pseudo-code."  The p-system
interprets the P-code and instructs the computer to execute
the appropriate machine language instructions. 
     "The built in MINI FILER program in the Operating
System (unit #14) file named SYSTEM.TI.FILER provides many
of the file management capabilities of the p-System Filer
program. {MINI FILER is in ROM. The p-System Filer program
is  extra cost disk software.}  Use the "G"o command from
the system command level to access the MINI FILER. 
     "When you enter the MINI FILER, a menu of "Special
p-System Commands" is displayed.  To select a menu option,
press the letter that precedes it. 
     A. Run a program 
     B. Copy a disk 
     C. Copy a file 
     D. Delete a file. 
     E. List files on a disk. 
     F. Format a new disk. 
     G. Clear a disk directory. 
     H. Combine free disk space. 
     I. Change name. 
     Q. Return to standard p-System menu. 
     ?. Help 
     S. Set single disk system.{Toggles to "multiple" disk} 

    "The TI Computer 99/8 provides several utilities that
enable you to access special capabilities of the computer
through TMS9900 assembly language.  With these utilities,
you can change the values of the VDP chip, access the DSR
for peripheral devices, scan the keyboard, kink a program to
GPL routines, and link to the Editor/Assembler loader.
Remember that these can only be used in TI assembly language
     "The following list gives each of the utilities
predefined in the REF/DEF table: VSBW VMBW VSBR VWBR KSCAN
     "The TI Computer 99/8 has more utilities available
through the Editor/Assembler than did the TI 99/4A Home
Computer.  As a result, the XMLLINK tables have been
changed, so old assembly language programs may need to
be updated 

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