The TI-99/4 and TI-99/4A are
home computers released by
Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
in 1979 and 1981, respectively. Based on the
Texas Instruments TMS9900
Introduced in June 1976, the TMS9900 was one of the first commercially available, single-chip 16-bit microprocessors. It implemented Texas Instruments' TI-990 minicomputer architecture in a single-chip format, and was initially used for low-end ...
microprocessor
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...
originally used in
minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
s, the TI-99/4 was the first
16-bit
16-bit microcomputers are microcomputers that use 16-bit microprocessors.
A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two mos ...
home computer.
The associated
video display controller
A video display controller or VDC (also called a display engine or display interface) is an integrated circuit which is the main component in a video-signal generator, a device responsible for the production of a TV video signal in a computing ...
provides color graphics and
sprite support which were only comparable with those of the
Atari 400 and 800 released a month after the TI-99/4.
The calculator-style keyboard of the TI-99/4 was cited as a weak point, and TI's reliance on
ROM cartridge
A ROM cartridge, usually referred to in context simply as a cartridge, cart, or card, is a replaceable part designed to be connected to a consumer electronics device such as a home computer, video game console or, to a lesser extent, electroni ...
s and their practice of limiting developer information to select third parties resulted in a lack of software for the system. The TI-99/4A was released in June 1981 to address some of these issues with a simplified internal design, full-travel keyboard, improved graphics, and a unique expansion system. At half the price of the original model, sales picked up significantly and TI supported the 4A with peripherals, including a speech synthesizer and a "Peripheral Expansion System" box to contain hardware add-ons. TI released developer information and tools, but the insistence on remaining sole publisher continued to starve the platform of software.
The 1981 US launch of the TI-99/4A followed Commodore's
VIC-20
The VIC-20 (known as the VC-20 in Germany and the VIC-1001 in Japan) is an 8-bit home computer that was sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the PE ...
by several months. Commodore CEO
Jack Tramiel
Jack Tramiel ( ; born Idek Trzmiel; December 13, 1928 – April 8, 2012) was an American businessman and Holocaust survivor, best known for founding Commodore International. The Commodore PET, VIC-20 and Commodore 64 are some home compute ...
did not like TI's
predatory pricing
Predatory pricing is a Pricing strategies, pricing strategy, using the method of undercutting on a larger scale, where a Article 102 of the Treaty on the Functioning of the European Union#Dominance, dominant firm in an industry will deliberately ...
in the mid-1970s and retaliated with a
price war
A price is the (usually not negative) quantity of payment or compensation given by one party to another in return for goods or services. In some situations, the price of production has a different name. If the product is a "good" in the c ...
by repeatedly lowering the price of the VIC-20 and forcing TI to do the same. By 1983, the 99/4A was selling at a loss for under . Even with the increased user base created by the heavy discounts, Texas Instruments lost US$330 million in the third quarter of 1983 and announced the discontinuation of the TI-99/4A in October 1983. Production ended in March 1984.
The TI-99/4 was intended to fit in the middle of a planned range of TI-99 computers, none of which were ultimately released but prototypes and documentation have been found after the TI-99/4A was discontinued.
Features
The TI-99/4A is a self-contained console with the
motherboard
A motherboard (also called mainboard, main circuit board, mb, mboard, backplane board, base board, system board, logic board (only in Apple computers) or mobo) is the main printed circuit board (PCB) in general-purpose computers and other expand ...
,
ROM cartridge
A ROM cartridge, usually referred to in context simply as a cartridge, cart, or card, is a replaceable part designed to be connected to a consumer electronics device such as a home computer, video game console or, to a lesser extent, electroni ...
slot, and full-travel keyboard in the same case. The power supply is external. An
RF modulator
An RF modulator (or radio frequency modulator) is an electronic device whose input is a baseband signal which is used to modulate a radio frequency source.
RF modulators are used to convert signals from devices such as media players, VCRs and ...
allows the use of a television as a monitor. Lowercase letters are displayed as
small caps
In typography, small caps (short for "small capitals") are characters typeset with glyphs that resemble uppercase letters (capitals) but reduced in height and weight close to the surrounding lowercase letters or text figures. This is technicall ...
, rather than separate glyphs.
TI BASIC, an
ANSI
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organi ...
-compliant
BASIC
BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College ...
interpreter based on
Dartmouth BASIC
Dartmouth BASIC is the original version of the BASIC programming language. It was designed by two professors at Dartmouth College, John G. Kemeny and Thomas E. Kurtz. With the underlying Dartmouth Time Sharing System (DTSS), it offered an inter ...
, is built-in and includes support for graphics, sound, and file system access. Later versions of the 99/4A, identified by
(C)1983 TEXAS INSTRUMENTS V2.2
on the title page, prevent the use of unlicensed
ROM
Rom, or ROM may refer to:
Biomechanics and medicine
* Risk of mortality, a medical classification to estimate the likelihood of death for a patient
* Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac
* R ...
cartridges from third-party manufacturers such as
Atarisoft
Atarisoft was a brand name used by Atari, Inc. in 1983 and 1984 to market video games the company published for home systems made by competitors. Each platform had a specific color attributed by Atarisoft for its game packages. For example, video ...
.
Peripherals include a 5¼"
floppy disk drive
A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...
and controller, an
RS-232
In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such a ...
card with two serial ports and one parallel port, a
P-code
Bytecode (also called portable code or p-code) is a form of instruction set designed for efficient execution by a software Interpreter (computing), interpreter. Unlike Human-readable code, human-readable source code, bytecodes are compact nume ...
card for
Pascal
Pascal, Pascal's or PASCAL may refer to:
People and fictional characters
* Pascal (given name), including a list of people with the name
* Pascal (surname), including a list of people and fictional characters with the name
** Blaise Pascal, Fren ...
support, a
thermal printer
Thermal printing (or direct thermal printing) is a digital printing process which produces a printed image by passing paper with a thermochromic coating, commonly known as thermal paper, over a print head consisting of tiny electrically heated ...
, a 300-baud
acoustic coupler
In telecommunications, an acoustic coupler is an interface device for coupling electrical signals by acoustical means—usually into and out of a telephone.
The link is achieved through converting electric signals from the phone line to sound a ...
, a
tape drive
A tape drive is a data storage device that reads and writes data on a magnetic tape. Magnetic tape data storage is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and a long archival stability.
...
using standard
audio cassettes
The Compact Cassette or Musicassette (MC), also commonly called the tape cassette, cassette tape, audio cassette, or simply tape or cassette, is an analog magnetic tape recording format for audio recording and playback. Invented by Lou Ottens ...
as media, and a 32
KB memory
expansion card
In computing, an expansion card (also called an expansion board, adapter card, peripheral card or accessory card) is a printed circuit board that can be inserted into an electrical connector, or expansion slot (also referred to as a bus slo ...
.
16-bit processor
Both TI-99/4 models use the
16-bit
16-bit microcomputers are microcomputers that use 16-bit microprocessors.
A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two mos ...
TMS9900
Introduced in June 1976, the TMS9900 was one of the first commercially available, single-chip 16-bit microprocessors. It implemented Texas Instruments' TI-990 minicomputer architecture in a single-chip format, and was initially used for low-end m ...
CPU
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...
running at 3
MHz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
. The TMS9900 is a single-chip implementation of a
TI-990 {{Short description, Series of 16-bit computers by Texas Instruments.
The TI-990 was a series of 16-bit minicomputers sold by Texas Instruments (TI) in the 1970s and 1980s. The TI-990 was a replacement for TI's earlier minicomputer systems, the T ...
minicomputer. Although a full 16-bit processor, only the system ROM and 256 bytes of scratchpad RAM are available on the 16-bit bus.
In order to build a complete 16-bit system, TI would have had to redesign many of their existing 8-bit support chips. Instead, TI decided to use existing devices for the majority of the system. The result was that only a small portion of the system was 16-bit, and used a second 8-bit
computer bus
In computer architecture, a bus (shortened form of the Latin '' omnibus'', and historically also called data highway or databus) is a communication system that transfers data between components inside a computer, or between computers. This ex ...
for the rest.
[
One of the key features of the TMS9900 from the minicomputer design that spawned it was the inclusion of several sets of ]processor register
A processor register is a quickly accessible location available to a computer's processor. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only. ...
s. Registers are used to store information that is being actively worked on by a particular program, as opposed to main memory
Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers.
The central processing unit (CPU) of a computer ...
which stores much more data but is slower to access. In a minicomputer setting, the system was typically running a time sharing
In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1
Its emergence a ...
or multitasking operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
, or being used for real-time computing
Real-time computing (RTC) is the computer science term for hardware and software systems subject to a "real-time constraint", for example from event to system response. Real-time programs must guarantee response within specified time constrai ...
, both of which benefit from being able to quickly switch among programs. To do this, the TMS9900 stored several sets of registers in main memory and could switch between the sets of sixteen 16-bit registers by changing the single workspace pointer register, thereby allowing very rapid context switch
In computing, a context switch is the process of storing the state of a process or thread, so that it can be restored and resume execution at a later point, and then restoring a different, previously saved, state. This allows multiple processes ...
ing.
The new design put 256 bytes of random access memory
Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A Random access, random-access memory device allows data items to b ...
(RAM) on the 16-bit bus to store up to eight sets of registers. This area of RAM is known as the "scratchpad memory". As the processor's instructions are all 16-bit as well, the 8 KB internal system read only memory
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing soft ...
(ROM) was also on the 16-bit side.[ Only the ]program counter
The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, is ...
, status register, and workspace pointer registers are actually implemented on the chip itself.[
Included on the 8-bit side of the system is the majority of the RAM and almost all of the support chips, especially the ]video display controller
A video display controller or VDC (also called a display engine or display interface) is an integrated circuit which is the main component in a video-signal generator, a device responsible for the production of a TV video signal in a computing ...
(VDP). All accesses to the VDP system are executed eight bits at a time. The system's RAM is managed by the VDP, which provides access to the CPU only when the CPU is not using the memory. This means that user programs and data has to be read over two machine cycles, essentially reducing speed by half. According to ''IEEE Spectrum'', this negates the performance advantage of a 16-bit processor.[
]
Video display processor
Graphics in the 99/4A are generated by a TMS9918A
VDP TMS9918A
VDP TMS9918A
VDP TMS9928A
The TMS9918 is a video display controller (VDC) manufactured by Texas Instruments, in manuals referenced as 'Video Display Processor' (VDP) and introduced in 1979. The TMS9918 and its variants were used i ...
Video Display Processor (VDP), with a variant for PAL territories. The VDP was developed by Texas Instruments and also sold independently, allowing it to be used in other systems. It serves as the video processor for the ColecoVision
ColecoVision is a second-generation home video-game console developed by Coleco and launched in North America in August 1982. It was released a year later in Europe by CBS Electronics as the CBS ColecoVision.
The console offered a closer expe ...
and SG-1000
The is a home video game console manufactured by Sega. It was Sega's first entry into the home video game hardware business. Developed in response to a downturn in arcades starting in 1982, the SG-1000 was created on the advice of Hayao Nakay ...
consoles, and an earlier model is part of the MSX
MSX is a standardized home computer architecture, announced by Microsoft and ASCII Corporation on June 16, 1983. It was initially conceived by Microsoft as a product for the Eastern sector, and jointly marketed by Kazuhiko Nishi, then vice-p ...
computer standard.
The TMS9918A supports character-based and bitmap display modes as well as hardware sprites. There are 32 single-color sprites total, but only a maximum of 4 can be displayed per scan line
A scan line (also scanline) is one line, or row, in a raster scanning pattern, such as a line of video on a cathode ray tube (CRT) display of a television set or computer monitor.
On CRT screens the horizontal scan lines are visually discernible ...
. Each sprite is either 8×8 or 16×16 pixels and can be scaled 2x to 16x16 or 32x32.
16 KB of RAM is provided for the Video Display Processor. VDP RAM is the largest block of writeable memory in the unexpanded TI-99/4A architecture, and is used for storing disk I/O buffers and
TI BASIC user programs. Access to this memory has to use the VDP as an intermediary.
Expansion
TI-99 peripherals contain device drivers in ROMs in the hardware. When a new peripheral is attached, it is immediately available for any software that wants to use it. All device access uses a generic file-based I/O mechanism, allowing new devices to be added without updating software. The Peripheral Expansion System can hold two RS-232 cards, for a total of four RS-232 ports and two parallel printer ports.
The computer supports two cassette drives through a dedicated port, using a custom data format. Composite video
Composite video is an analog video signal format that carries standard-definition video (typically at 525 lines or 625 lines) as a single channel. Video information is encoded on one channel, unlike the higher-quality S-Video (two channels) a ...
and audio are output through another port on NTSC
The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
-based machines, and combine through an external RF modulator for use with a television. PAL
Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...
-based machines output a more complex YUV signal which is also modulated to UHF externally.
Two digital joystick
A joystick, sometimes called a flight stick, is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal cont ...
s can be connected through a single DE-9
The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems.
Description, no ...
port. It is identical to the Atari joystick port
The Atari joystick port is a computer port used to connect various gaming controllers to game console and home computer systems in the 1970s to the 1990s. It was originally introduced on the Atari 2600 in 1977 and then used on the Atari 400 an ...
, but with incompatible pins. Aftermarket adapters allow the use of Atari compatible joysticks.
TI sold an official 32 KB RAM expansion. The memory is not available to all uses. For example, an Extended Basic program is restricted to using 24 KB with the remaining 8 KB available for machine code routines. The Mini Memory plug-in module contains 4 KB of battery-backed RAM that can be used as a persistent RAM disk or to load a machine-code program.
Peripheral Expansion Box
The TI-99/4A can be upgraded via expansion cards added to an eight-slot, external chassis containing its own linear power supply and a full-height 5¼" floppy bay. Encased in silver plastic, but made from sheet steel, this is labeled as the Peripheral Expansion System by TI, but usually called the Peripheral Expansion Box or PEB. Each card has an LED
A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
that blinks or flickers when being accessed by software. The section of the power supply that powers the card slots is unregulated. Each card has on-board regulators for its own requirements, which reduces power consumption on a partially-loaded PEB, allowing for cards with unusual voltage requirements.
The PEB carries an analog sound input on the expansion bus, allowing the Speech Synthesizer's audio to be carried through the console to the monitor. The audio is also carried through the ribbon cable
A ribbon cable (also known as multi-wire planar cable) is a cable with many conducting wires running parallel to each other on the same flat plane. As a result, the cable is wide and flat. Its name comes from its resemblance to a piece of ribb ...
to the PEB, both allowing the relocation of the Speech Synthesizer to the PEB and the possibility of audio cards offering more features than the console's built-in sound. No official cards from TI do this.
Official cards from TI that were released and could be placed inside the PEB include
* 32 kB RAM expansion card
* RS 232 and parallel port card
* P-code card, implementing the UCSD p-system IV.0 by acting as a ROM-disk
* Diskette drive control card. The design allowed controlling both drives internally in the PEB and external drives.
Peripherals designed to be used without the PEB existed too.
Speech synthesizer
In the late 1970s and early 1980s, TI was a pioneer in speech synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware products. A text-to-speech (TTS) system converts normal languag ...
because of its Texas Instruments LPC Speech Chips
The Texas Instruments LPC Speech Chips are a series of speech synthesizer digital signal processor integrated circuits created by Texas Instruments beginning in 1978. They continued to be developed and marketed for many years, though the speech dep ...
which were used in its Speak & Spell toys. A plug-in speech synthesizer module was available for the TI-99/4 and 4A. Speech synthesizers were offered free with the purchase of a number of cartridges and were used by video games such as '' Alpiner'' and ''Parsec''. ''Alpiner''s speech includes male and female voices and can be sarcastic when the player makes a bad move.
The synthesizer uses a variant of linear predictive coding
Linear predictive coding (LPC) is a method used mostly in audio signal processing and speech processing for representing the spectral envelope of a digital signal of speech in compressed form, using the information of a linear predictive model. ...
and has a small in-built vocabulary. The original intent was to release small cartridges that plugged directly into the synthesizer unit to increase the device's vocabulary. However, the success of software text-to-speech
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware products. A text-to-speech (TTS) system converts normal languag ...
in the Terminal Emulator II cartridge cancelled that plan.
History
In 1977, groups within Texas Instruments were designing a video game console
A video game console is an electronic device that Input/output, outputs a video signal or image to display a video game that can be played with a game controller. These may be home video game console, home consoles, which are generally placed i ...
, a home computer to compete against the TRS-80 and Apple II, and a high-end business personal computer with a hard drive
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnet ...
. The first two groups were both working at TI's consumer products division in Lubbock, Texas
Lubbock ( )
is the 10th-most populous city in the U.S. state of Texas and the seat of government of Lubbock County. With a population of 260,993 in 2021, the city is also the 85th-most populous in the United States. The city is in the northw ...
, and continually competed. According to Wally Rhines
Walden C. “Wally” Rhines (born November 11, 1946) is an American engineer and businessman. Rhines is President and CEO of Cornami, Inc., a fabless semiconductor company focused on fully homomorphic encryption. Previously, he was President and ...
, the 99/4's "ultracheap keyboard" (with calculator-style keys), RF modulator
An RF modulator (or radio frequency modulator) is an electronic device whose input is a baseband signal which is used to modulate a radio frequency source.
RF modulators are used to convert signals from devices such as media players, VCRs and ...
, and ROM cartridges came from the console design. Eventually, the two teams were merged and directed towards the home computer market. Meanwhile, the third team was merged into TI's Data Systems Division, which had a line of minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
products and various computer terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and ...
s; they viewed the all-in-one machine as a threat and the project was eventually killed.
Others within the company persuaded the Lubbock group to use TI's TMS9900 CPU. This was in keeping with TI's "one company, one computer architecture" concept, where a single processor model would scale from consoles to its high-end minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
s. The TMS9900 is a single-chip implementation of TI's 16-bit TI-990 {{Short description, Series of 16-bit computers by Texas Instruments.
The TI-990 was a series of 16-bit minicomputers sold by Texas Instruments (TI) in the 1970s and 1980s. The TI-990 was a replacement for TI's earlier minicomputer systems, the T ...
mini design, and is the CPU in low-end models of that platform. Feature-limited single-chip versions of popular minicomputer designs from the 1960s were popular in the mid-1970s and newly designed 16-bit and 32-bit CPUs like the Intel 8088
The Intel 8088 ("''eighty-eighty-eight''", also called iAPX 88) microprocessor is a variant of the Intel 8086. Introduced on June 1, 1979, the 8088 has an eight-bit external data bus instead of the 16-bit bus of the 8086. The 16-bit registers an ...
and Motorola 68000
The Motorola 68000 (sometimes shortened to Motorola 68k or m68k and usually pronounced "sixty-eight-thousand") is a 16/32-bit complex instruction set computer (CISC) microprocessor, introduced in 1979 by Motorola Semiconductor Products Sector ...
, respectively, quickly rendered these earlier designs obsolete. Many of the TMS9900's quirky features, like processor register
A processor register is a quickly accessible location available to a computer's processor. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only. ...
s in main memory
Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers.
The central processing unit (CPU) of a computer ...
, came from its minicomputer roots where such concepts were more common.
Meanwhile, another home computer product was emerging from TI's European headquarters, where a third party consulting firm was contracted to produce a prototype codenamed "Mojo". This was based on TI's version of the 8-bit
In computer architecture, 8-bit Integer (computer science), integers or other Data (computing), data units are those that are 8 bits wide (1 octet (computing), octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) arc ...
Intel 8080
The Intel 8080 (''"eighty-eighty"'') is the second 8-bit microprocessor designed and manufactured by Intel. It first appeared in April 1974 and is an extended and enhanced variant of the earlier 8008 design, although without binary compatibil ...
supported by an all-TI chip set. After a series of discussions, Mojo was abandoned and the Consumer Products concept moved forward.
99/4
In 1979, TI was a successful manufacturer of large computers and was the largest semiconductor manufacturer in the world. Its catalog included a huge variety of analog and digital integrated circuits already widely used in the microcomputers, giving it a single-source advantage no other company could meet. It used this position to take over markets, as it did in the mid-1970s introducing its first scientific calculator
A scientific calculator is an electronic calculator, either desktop or handheld, designed to perform mathematical operations. They have completely replaced slide rules and are used in both educational and professional settings.
In some areas ...
s. These underpriced its former customers like Commodore
Commodore may refer to:
Ranks
* Commodore (rank), a naval rank
** Commodore (Royal Navy), in the United Kingdom
** Commodore (United States)
** Commodore (Canada)
** Commodore (Finland)
** Commodore (Germany) or ''Kommodore''
* Air commodore, a ...
and drove them out of the calculator business. Observers expected TI would do the same to the microcomputer market if it released a competitive system. ''The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...
'' suggested that the entry of TI and Hewlett-Packard
The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company headquartered in Palo Alto, California. HP developed and provided a wide variety of hardware components ...
would reshape the entire industry.
Through the development period, several companies attempting to enter the home computer market were faced with significant pushback from the Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction ...
(FCC). The FCC had developed new rules for consumer devices that connected directly to television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
s in an effort to control ongoing complaints about interference by poorly shielded devices. Televisions of the era generally had only a single antenna input, and thus connecting to them required the internal video signal of the device to be converted to radio frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upp ...
using an RF modulator
An RF modulator (or radio frequency modulator) is an electronic device whose input is a baseband signal which is used to modulate a radio frequency source.
RF modulators are used to convert signals from devices such as media players, VCRs and ...
. The resulting signals were often poorly shielded and signal leakage could be picked up in the antennas of nearby televisions.
The new rules were extremely difficult to meet. TI continued battling the FCC both in the lab and in Congress, where it had considerable power due to its position within Texas's high-tech industry. It failed to meet the FCC requirements as the release date approached. The company eventually gave up and bundled a modified Zenith Electronics
Zenith Electronics, LLC, is an American research and development company that develops ATSC and digital rights management technologies. It is owned by the South Korean company LG Electronics. Zenith was previously an American brand of consumer el ...
television as a computer monitor
A computer monitor is an output device that displays information in pictorial or textual form. A discrete monitor comprises a visual display, support electronics, power supply, housing, electrical connectors, and external user controls.
The di ...
, eliminating the need for the RF modulator
An RF modulator (or radio frequency modulator) is an electronic device whose input is a baseband signal which is used to modulate a radio frequency source.
RF modulators are used to convert signals from devices such as media players, VCRs and ...
that generates the interference by connecting directly to the TV's circuitry using a composite video
Composite video is an analog video signal format that carries standard-definition video (typically at 525 lines or 625 lines) as a single channel. Video information is encoded on one channel, unlike the higher-quality S-Video (two channels) a ...
signal. This put the introductory price at .
The 99/4 sold poorly. Very little software was available, as few developers ported their products to its 16-bit CPU. The machine was met with almost universal disdain when it was released. Every review complained about the keyboard, the lack of lower case characters, any sort of expansion, and lack of software. In July 1980, Adam Osborne
Adam Osborne (March 6, 1939 – March 18, 2003) was a British author, book and software publisher, and computer designer who founded several companies in the United States and elsewhere. He introduced the Osborne 1, the first commercially su ...
reported that, despite poor sales, TI had raised the price of a complete system to , higher than the popular Apple II, which started at . Osborne said, "Some dealers, who have offered the complete system (including the monitor) for less than the price of the Apple, have still been unable to sell it". TI sold fewer than 20,000 computers by summer 1981, less than one tenth Apple or Radio Shack's volume; even Atari, Inc.
Atari, Inc. was an American video game developer and home computer company founded in 1972 by Nolan Bushnell and Ted Dabney. Atari was a key player in the formation of the video arcade and video game industry.
Based primarily around the Sunny ...
, which reportedly lost on sales of of computers, had an Atari 8-bit family
The Atari 8-bit family is a series of 8-bit home computers introduced by Atari, Inc. in 1979 as the Atari 400 and Atari 800. The series was successively upgraded to Atari 1200XL , Atari 600XL, Atari 800XL, Atari 65XE, Atari 130XE, Atari 800XE, ...
installed base more than twice as large. David H. Ahl
David H. Ahl (born May 17, 1939) is an American author who is the founder of ''Creative Computing (magazine), Creative Computing'' magazine. He is also the author of many how-to books, including ''BASIC Computer Games'', the first computer book t ...
described the 99/4 as "vastly overpriced, particularly considering its strange keyboard, non-standard Basic, and lack of software". The ''Times'' called it an "embarrassing failure".
99/4A
Two years after the 99/4's debut, TI released the 99/4A. It adds a typewriter-style keyboard—keeping the non-standard layout—and more expansion options. The expansion system extends from the right side of the chassis, with modules that can be daisy-chained. There is a practical limitation to this, because each module increases the width of the system. The price was initially , less than half that of the 99/4.
TI continued lowering the price through 1981, first to , and then to in early 1982, in competition with Commodore's VIC-20
The VIC-20 (known as the VC-20 in Germany and the VIC-1001 in Japan) is an 8-bit home computer that was sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the PE ...
. This turned into a price war
A price is the (usually not negative) quantity of payment or compensation given by one party to another in return for goods or services. In some situations, the price of production has a different name. If the product is a "good" in the c ...
with Commodore. TI responded by cutting the wholesale price of the 99 by , while also offering a rebate directly to consumers, lowering the street price to about . TI spokesman Bill Cosby
William Henry Cosby Jr. ( ; born July 12, 1937) is an American stand-up comedian, actor, and media personality. He made significant contributions to American and African-American culture, and is well known in the United States for his eccentric ...
joked how easy it was to sell a computer by paying people to buy one. By mid-1982, Jerry Pournelle
Jerry Eugene Pournelle (; August 7, 1933 – September 8, 2017) was an American scientist in the area of operations research and human factors research, a science fiction writer, essayist, journalist, and one of the first bloggers. In the 1960s ...
wrote that TI was "practically giving away the TI-99/4A". An industry joke stated that the company was losing money on each computer, but was making up for it in volume. Commodore matched the price in December 1982.
TI celebrated the 99/4A's market success at the January 1983 Consumer Electronics Show
CES (; formerly an initialism for Consumer Electronics Show) is an annual trade show organized by the Consumer Technology Association (CTA). Held in January at the Las Vegas Convention Center in Winchester, Nevada, United States, the event typi ...
in Las Vegas. Sales peaked at 30,000 a week that month, but on 10 January 1983 Commodore lowered the price of its computers. In February TI responded with a 99/4A retail price of . In April, the VIC-20's bundled retail price reached and the 99/4A followed suit. In the spring of 1983, TI attempted to reduce the parts count to maintain a competitive edge by combining multiple chips into a single custom chip, renaming the 4A PCB as a "QI" (Quality Improved) board and began production of plastic beige cases without the former aluminum trim of the black console. In May, it began offering the PEB for free with the purchase of three peripherals. In August the company reduced prices of peripherals by 50% and offered of free software; in September, it reduced software prices by up to 43%.
The president of Spectravideo
Spectravideo International (SVI) was an American computer manufacturer and software house. It was originally called SpectraVision, a company founded by Harry Fox in 1981. The company produced video games and other software for the VIC-20 home c ...
later said that "TI got suckered by" Jack Tramiel
Jack Tramiel ( ; born Idek Trzmiel; December 13, 1928 – April 8, 2012) was an American businessman and Holocaust survivor, best known for founding Commodore International. The Commodore PET, VIC-20 and Commodore 64 are some home compute ...
, head of Commodore. TI was forced to sell the 99/4A for about the same price as the VIC-20, even though it was much more expensive to manufacture.
Lack of third-party development
TI could not make a profit on the TI-99/4A at a price of $99, but hoped that selling many inexpensive computers would increase sales of more profitable software and peripherals. Because such a razor and blades business model
The razor and blades business model is a business model in which one item is sold at a low price (or given away for free) in order to increase sales of a complementary good, such as consumable supplies. It is different from loss leader marketing ...
requires that such products be its own, TI strictly controlled development for the computer, discouraging hobbyists and third-party developers. It wanted unsophisticated consumers to buy its computers like an appliance, and not technical users who might want to write their own software, despite the latter being what Pournelle described as "a large unpaid R&D department" for computer companies. The company advertised its calculators in almost every issue of ''BYTE'' starting in 1980, but deliberately excluded its home computer from the ads except briefly in late 1982. TI also used its preexisting calculator sales channel of mass-market retailers, and not specialized computer stores.
TI did not provide an editor, assembler, or hardware technical information when it released the computer. Pournelle stated that "TI's message is loud and clear: 'Drop dead, hobbyists!, and added that the company "worked very hard at keeping you outside the machine". Citing ''Money
Money is any item or verifiable record that is generally accepted as payment for goods and services and repayment of debts, such as taxes, in a particular country or socio-economic context. The primary functions which distinguish money are as ...
'', publisher of ''Kilobaud Microcomputing
''Kilobaud Microcomputing'' was a magazine dedicated to the computer homebrew hobbyists from 1977 to 1983.
How ''kilobaud'' started
Wayne Green, the editor and publisher of ''kilobaud'', had been the publisher of ''BYTE'' magazine, (another i ...
'' Wayne Green
Wayne Sanger Green II (September 3, 1922 – September 13, 2013) was an American publisher, writer, and consultant. Green was editor of '' CQ'' magazine before he went on to found '' 73'', ''80 Micro'', ''Byte'', ''CD Review'', ''Cold Fusion'', ...
reported in August 1980 that TI planned to have only 100 applications available by the end of 1981, stating that "This tiny figure has to put a chill on the whole industry". Green's company, Instant Software Instant Software was a company that produced game, utility, and education software in the late 1970s and early 1980s primarily for the TRS-80 line of home computers. Instant Software was a subsidiary of Kilobaud Microcomputing, headquartered in Pete ...
, was a prolific publisher of TRS-80
The TRS-80 Micro Computer System (TRS-80, later renamed the Model I to distinguish it from successors) is a desktop microcomputer launched in 1977 and sold by Tandy Corporation through their Radio Shack stores. The name is an abbreviation of '' ...
software, but could not find anyone to port software to the TI. He wrote, "We understand the problems with the system and the efforts Texas Instruments made to make translation difficult". A Spinnaker Software
Spinnaker Software was a software company founded in 1982John Case. ''Digital Future'', William Morrow : New York, N.Y. 1985. p. 122. known primarily for its line of non-curriculum based educational software, which was a major seller during the ...
executive said that the 99/4A had "the worst software in the business", and Ahl noted that unlike other computers, it did not have "Microsoft BASIC
Microsoft BASIC is the foundation software product of the Microsoft company and evolved into a line of BASIC interpreters and compiler(s) adapted for many different microcomputers. It first appeared in 1975 as Altair BASIC, which was the first ve ...
, VisiCalc
VisiCalc (for "visible calculator") is the first spreadsheet computer program for personal computers, originally released for Apple II by VisiCorp on 17 October 1979. It is often considered the application that turned the microcomputer from a hob ...
, WordStar
WordStar is a word processor application for microcomputers. It was published by MicroPro International and originally written for the CP/M-80 operating system, and later written also for MS-DOS and other 16-bit PC OSes. Rob Barnaby was the sol ...
, or any popular games". Peripherals cost about twice as much as for other computers. TI joysticks, for example, were of poor quality and difficult to find; one reseller reported that its best-selling product was the Atari CX40 joystick
The Atari CX40 joystick was the first widely used cross-platform game controller. The original CX10 was released with the Atari Video Computer System (later renamed the Atari 2600) in 1977 and became the primary input device for most games on the ...
adapter cable.
Pournelle added, "TI had rightly concluded that the hobbyists and hackers were a tiny part of the market and ''wrongly'' concluded that they were therefore unimportant". Rivals were more open with information. ''Kilobaud Microcomputing'' reported that a Commodore executive promised the VIC-20 would have "enough additional documentation to enable an experienced programmer/hobbyist to get inside and let his imagination work". Even when competitors did not disclose technical information, because their computers used commercial off-the-shelf
Commercial off-the-shelf or commercially available off-the-shelf (COTS) products are packaged or canned (ready-made) hardware or software, which are adapted aftermarket to the needs of the purchasing organization, rather than the commissioning of ...
parts like the MOS 6502
The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small te ...
and Zilog Z-80, much more information was public than for TI's proprietary components. IBM learned from TI's mistake, Pournelle said. The company released software and hardware technical information when the IBM PC
The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible de facto standard. Released on August 12, 1981, it was created by a team ...
was announced in 1981, stating that "the definition of a personal computer ''is'' third-party hardware and software".
TI had also learned from its mistake and no longer ignored hobbyists, Pournelle said in 1982. The company did advertise in ''BYTE'' its program for publishing others' software, and job openings for software developers. It insisted on being the sole publisher for the system, however, which many developers refused to agree to. After third-party developer
A video game developer is a broad term for a software developer specializing in video game development – the process and related disciplines of creating video games. A game developer can range from one person who undertakes all tasks to a large ...
s' games for the Atari 2600 became very successful, TI at the June 1983 Consumer Electronics Show
CES (; formerly an initialism for Consumer Electronics Show) is an annual trade show organized by the Consumer Technology Association (CTA). Held in January at the Las Vegas Convention Center in Winchester, Nevada, United States, the event typi ...
announced that only cartridges with a TI-licensed lockout chip
In a general sense, a lockout chip is a chip within an electronic device to prevent other manufacturers from using a company's device to perform certain functions.
A notable example is the lockout chip found in Nintendo's Nintendo Entertainment Sy ...
would work in the 99/4A. The ''Boston Phoenix
''The Phoenix'' (stylized as ''The Phœnix'') was the name of several alternative weekly periodicals published in the United States of America by Phoenix Media/Communications Group of Boston, Massachusetts, including the ''Portland Phoenix'' and ...
'' predicted that "most oftware developersjust won't bother making TI-compatible versions of their programs", and Pournelle wrote that "TI once again tells the hobbyists to drop dead".
No official technical documentation from TI was released until the "Editor/Assembler" development suite was released in 1981, and no system schematics were ever released to the public until after TI had discontinued the computer.
Discontinuation
After TI in mid-1983 unexpectedly announced a loss in the second calendar quarter—implying a pretax loss from home computers of —its stock dropped by one third in two days. The ''Times'' stated in June 1983 that Cosby's refund "joke is no longer funny", and that "future options are slim". The low price affected the 99/4A's reputation; "When they went to , people started asking 'What's wrong with it?'", one retail executive said. An L.F. Rothschild
L.F. Rothschild (later known as L.F. Rothschild, Unterberg, Towbin) was a merchant and investment banking firm based in the United States and founded in 1899. The firm collapsed following the 1987 stock market crash.
History
L.F. Rothschild ...
sell-side analyst
A sell-side analyst works for a brokerage firm and evaluates companies for future earnings growth and other investment criteria. They sometimes place recommendations on stocks or other securities, typically phrased as "buy", "sell", or "hold." T ...
estimated that TI had prepared to manufacture three million computers in 1983, but would only be able to sell two million.
Some observers predicted after the second quarter's loss that the 99/4A would not be able to recover; even if the company did not plan to discontinue the computer, the fear that it would become orphaned technology
Orphaned technology is a descriptive term for computer products, programs, and platforms that have been abandoned by their original developers. Orphaned technology refers to software, such as abandonware and antique software, but also to computer ...
might cause retailers to avoid ordering inventory. Others thought that TI could sell excess inventory and continue producing the computer. After losing after taxes in the third calendar quarter of 1983, TI announced plans to discontinue the 99/4A, while continuing to sell the TI Professional MS-DOS
MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few ope ...
-compatible computer. (TI stock rose by 25% after the announcement, because the company's other businesses were strong.) With another TI price cut, retailers sold remaining inventory of the former computer during Christmas for $49. The 90 Child World
Child World was an American toy retailer founded in 1962. It grew to 182 sites and revenues of $830 million before failing in 1992. It was known for the distinctive stylised castle store exterior adopted after its 1977 purchase of the Children's ...
stores quickly sold over 40,000 computers at a price referred to as "nearly a stocking stuffer" in a ''Times'' article.
A total of 2.8 million units were shipped before the TI-99/4A was discontinued in March 1984.[ The 99/4A became the first in a series of home computers to be orphaned by their manufacturer over the next few years, along with the ]Coleco Adam
The Coleco Adam is a home computer and expansion device for the ColecoVision released in 1983 by American toy and video game manufacturer Coleco. It was an attempt to follow on the success of the company's ColecoVision video game console. The Ad ...
, Mattel Aquarius
Aquarius is a home computer designed by Radofin and released by Mattel Electronics in 1983. Based on the Zilog Z80 microprocessor, the system has a rubber chiclet keyboard, 4K of RAM, and a subset of Microsoft BASIC in ROM. It connects to a tel ...
, Timex Sinclair 1000
The Timex Sinclair 1000 (or T/S 1000) was the first computer produced by Timex Sinclair, a joint venture between Timex Corporation and Sinclair Research. It was launched in July 1982, with a US sales price of US$99.95, making it the cheapest home ...
, and IBM PCjr
The IBM PCjr (pronounced "PC junior") was a home computer produced and marketed by IBM from March 1984 to May 1985, intended as a lower-cost variant of the IBM PC with hardware capabilities better suited for video games, in order to compete mor ...
.
Architecture
The TMS9900's machine language
In computer programming, machine code is any low-level programming language, consisting of machine language instructions, which are used to control a computer's central processing unit (CPU). Each instruction causes the CPU to perform a very ...
instructions must be word-aligned, so at least 16-bits are needed for every instruction. At the time, memory was expensive, so the size of this format was a concern. Additionally, programming the 8-bit side of the system from 16-bit code is somewhat complex. To address this, TI built a pseudo-assembly language
In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence be ...
known as "Graphic Programming Language", or GPL. This is a compact 8-bit language interpreted by the CPU which dynamically translates the GPL instructions into one or more TMS9900 instructions. GPL also includes utility routines that appear as single instructions in GPL code, allowing complex operations to be reduced to small sequences of code. For example, a block of memory can be cleared with a single instruction. All software originally distributed on ROM cartridge
A ROM cartridge, usually referred to in context simply as a cartridge, cart, or card, is a replaceable part designed to be connected to a consumer electronics device such as a home computer, video game console or, to a lesser extent, electroni ...
s were written using GPL, and are sometimes referred to as GROMs.
At the time of launch, the system included only a single user-accessible programming language
A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language.
The description of a programming ...
: TI's built-in BASIC interpreter, written in GPL. On the Creative Computing Benchmark
The Creative Computing Benchmark, also called Ahl's Simple Benchmark, is a computer benchmark that was used to compare the performance of the BASIC programming language on various machines. It was first introduced in the November 1983 issue of ''Cr ...
, it runs at roughly half the speed of the Apple II
The Apple II (stylized as ) is an 8-bit home computer and one of the world's first highly successful mass-produced microcomputer products. It was designed primarily by Steve Wozniak; Jerry Manock developed the design of Apple II's foam-m ...
.
Technical specifications
CPU
Texas Instruments TMS9900
Introduced in June 1976, the TMS9900 was one of the first commercially available, single-chip 16-bit microprocessors. It implemented Texas Instruments' TI-990 minicomputer architecture in a single-chip format, and was initially used for low-end ...
@ 3 MHz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
, 16-bit
16-bit microcomputers are microcomputers that use 16-bit microprocessors.
A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two mos ...
, 64-pin DIP
Memory
* 8 kB of monitor ROM and GPL interpreter
* 8 kB of RAM, if memory expansion is attached
* 8 kB allocated to expansion devices (e.g. disk drive controller)
* 8 kB allocated to ROM/RAM in expansion cartridges
*256 bytes scratchpad RAM for the CPU
* Memory ports for Video Display Processor, sound, speech etc.
* 24 kB RAM, if memory expansion is attached
*16 kB Video Display Processor RAM accessible via the VDP (not in CPU's memory map)
Video
TMS9918A
VDP TMS9918A
VDP TMS9918A
VDP TMS9928A
The TMS9918 is a video display controller (VDC) manufactured by Texas Instruments, in manuals referenced as 'Video Display Processor' (VDP) and introduced in 1979. The TMS9918 and its variants were used i ...
VDP, 40 pin DIP. The earlier 99/4 uses the TMS9918. PAL systems use the "9929" versions of each.
* 32 single-color sprites in defined layers allowing higher-numbered sprites to transparently flow over lower-numbered sprites. Sprites are available at 8×8 pixels or 16×16 pixels, with a "magnify" bit that doubled all sprites' size but not their resolution. A single bit is available in hardware for collision detection, and the console supports automatic movement via an interrupt routine in the ROM. There can only be 4 visible sprites per scan line
A scan line (also scanline) is one line, or row, in a raster scanning pattern, such as a line of video on a cathode ray tube (CRT) display of a television set or computer monitor.
On CRT screens the horizontal scan lines are visually discernible ...
.
* 16 fixed colors (15 visible, one color reserved for "transparent" which shows the background color). Transparent is intended for the 9918's genlock
Genlock (generator locking) is a common technique where the video output of one source (or a specific reference signal from a signal generator) is used to synchronize other picture sources together. The aim in video applications is to ensure the ...
which is disabled in the system.
* Text mode: 40×24 characters (256 6×8 user-definable characters, no sprites, foreground and background color only, not accessible in BASIC, standard in the p-system/Pascal, assembly editor and word processor)
* Graphics mode: 32×24 characters (256 8×8 user-definable characters, full 15 color palette + transparent (available in groups of 8 through the character table) and 32 sprites (The only mode available in BASIC. Extended BASIC is required for sprites, and can access only 28 of them.)
* Bitmap mode: 256×192 pixels (no more than two colors in an eight-pixel row, full 15 color palette + transparent, all 32 sprites available but interrupt-based motion through the ROM routine is not due to the memory layout, not available to BASIC or the original 9918).
* Multicolor mode: 64×48 pixels (each pixel may be any color, all 32 sprites are available)
* All of the above comprise 36 layers starting with the video overlay input, then the background color, then two graphics mode layers, then a layer for each of the 32 sprites. A higher layer obscures a lower layer in hardware, unless that higher layer is transparent.
Sound
TMS9919, later SN94624
The SN76489 Digital Complex Sound Generator (DCSG) is a TTL-compatible programmable sound generator chip from Texas Instruments. Its main application was the generation of music and sound effects in game consoles, arcade games and home comput ...
, identical to the SN76489
The SN76489 Digital Complex Sound Generator (DCSG) is a TTL-compatible programmable sound generator chip from Texas Instruments. Its main application was the generation of music and sound effects in game consoles, arcade games and home computer ...
used in many other systems
* 3 voices, 1 noise (white or periodic)
* Voices generate square waves from 110 Hz to approximately 115 kHz
* Console ROM includes interrupt-driven music playback
Games
Roughly 100 games were published for the TI-99/4A, with most published by Texas Instruments. Some of the games released only for the 99/4A are ''Parsec'', ''Alpiner'', '' Tombstone City: 21st Century'', ''Tunnels of Doom
''Tunnels of Doom'' is a role-playing video game programmed by Kevin Kenney for the TI-99/4A home computer and published by Texas Instruments on December 31, 1982. It was available in two formats: cartridge with accompanying disk and cartridge wi ...
'', and '' The Attack''. ''TI Invaders
''TI Invaders'' is a fixed shooter video game published by Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integr ...
'' and ''Car Wars'' are TI's renditions of ''Space Invaders
is a 1978 shoot 'em up arcade game developed by Tomohiro Nishikado. It was manufactured and sold by Taito in Japan, and licensed to the Midway division of Bally for overseas distribution. ''Space Invaders'' was the first fixed shooter and set ...
'' and '' Head On'' respectively. ''Munch Man
''Munch Man'' (inconsistently written in the manual as ''Munchman'') is a video game written by Jim Dramis for the TI-99/4A home computer and published as a cartridge by Texas Instruments in 1982. Based on Namco's ''Pac-Man'', it includes severa ...
'' is similar to ''Pac-Man
originally called ''Puck Man'' in Japan, is a 1980 maze action video game developed and released by Namco for arcades. In North America, the game was released by Midway Manufacturing as part of its licensing agreement with Namco America. Th ...
'', but the title character fills the maze with a pattern rather than emptying it of dots.
Tigervision
Tigervision was a subsidiary of Tiger Toys which produced video games for the Atari 2600, Atari 8-bit family, TI-99/4A, VIC-20 and Commodore 64. Most of their games were ports. '' Polaris'' and '' River Patrol'' were originally arcade games from ...
offered a solution to the memory limitation of the standard cartridge slot in the form of a 24kB memory expansion cartridge that attached to the side expansion interface, emulating an expansion device. This allowed the company to implement a larger game completely in machine code, which was used for ''Espial'' and ''Miner 2049er
''Miner 2049er'' is a platform game created by Bill Hogue that was released in 1982 by Big Five Software. It was developed for the Atari 8-bit family and widely converted to other systems. The title "Miner 2049er" evokes a 21st-century take on th ...
''. Exceltec also released two similar side cartridges: ''Arcturus'' and ''Killer Caterpillar''.
The media criticized the computer's game library as mediocre. TI not only discouraged third-party development, including games, but it also failed to license popular arcade games like ''Zaxxon
is an isometric shooter arcade game, developed and released by Sega in 1982, in which the player pilots a ship through heavily defended space fortresses. Japanese electronics company Ikegami Tsushinki is also credited for having worked on the d ...
'' and ''Frogger
is a 1981 arcade action game developed by Konami and manufactured by Sega. In North America, it was released by Sega/Gremlin. The object of the game is to direct a series of frogs to their homes by crossing a busy road and a hazardous rive ...
''.
Unreleased hardware
Hex-Bus
The Hex-Bus
The Texas Instruments Hex-Bus interface (sometimes used unhyphenated as Hex Bus and with varying capitalization) was designed in 1982 and intended for commercial release in late 1983. It connects the console to peripherals via a high-speed serial ...
interface was designed in 1982 and intended for commercial release in late 1983. It connects the console to peripherals via a high-speed serial link. Though it is similar to today's USB
Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad v ...
(plug and play, hot-swappable, etc.), it was never released, with only a small number of prototypes appearing in collector hands after TI pulled out of the market.
TI-99/4A successors
The TI-99/4 was intended to fit in the middle of a planned range of TI-99 computers, with prototypes and documentation created for other models. Initial plans were for a lower-end TI-99/2 and a more powerful TI-99/8. Later ideas for expanding the range included a bargain-priced TI-99/3, a terminal TI-99/7, and a direct follow-up to the TI-99/4A referred to as either TI-99/4B or TI-99/5.
At the time they left the home computer market, TI had been actively developing two successors to the TI-99/4A that went through several prototypes but never entered production. Some of these prototypes are now in the hands of TI-99/4A collectors. Both machines would have been substantially faster than the original TI-99/4A and used the Hex-Bus
The Texas Instruments Hex-Bus interface (sometimes used unhyphenated as Hex Bus and with varying capitalization) was designed in 1982 and intended for commercial release in late 1983. It connects the console to peripherals via a high-speed serial ...
serial interface.
* TI-99/2, a 4K RAM, 32K ROM computer with no color, sound, or joystick port and a Mylar
BoPET (biaxially-oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and aro ...
keyboard. TI designed the computer in four and a half months to sell for under $100 and compete with the Sinclair ZX81
The ZX81 is a home computer that was produced by Sinclair Research and manufactured in Dundee, Scotland, by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and designed to be a low-cost ...
and Timex Sinclair 1000
The Timex Sinclair 1000 (or T/S 1000) was the first computer produced by Timex Sinclair, a joint venture between Timex Corporation and Sinclair Research. It was launched in July 1982, with a US sales price of US$99.95, making it the cheapest home ...
. Based on the TMS9995 CPU running at 10.7 MHz and with a built-in RF modulator, performance greatly increased when the screen was blank. The University of Southwestern Louisiana
The University of Louisiana at Lafayette (UL Lafayette, University of Louisiana, ULL, or UL) is a public research university in Lafayette, Louisiana. It has the largest enrollment within the nine-campus University of Louisiana System and the s ...
developed system software. 99/2 software ran on the 99/4A, but not vice versa. Working prototypes appeared at the January 1983 Consumer Electronic Show (CES). Home-computer prices declined so quickly, however, that by mid-1983 the 99/4A sold for $99. The company canceled the 99/2 in April 1983, but planned to exhibit it at the June CES until other companies' press conferences there indicated that competition would increase.
* TI-99/8 and 99/6. The 99/8 reportedly had a $200 wholesale price. Privately shown to dealers but not announced at June CES, it was formally canceled in October 1983. It included 64 kB of RAM expandable to 15 megabyte
The megabyte is a multiple of the unit byte for digital information. Its recommended unit symbol is MB. The unit prefix ''mega'' is a multiplier of (106) in the International System of Units (SI). Therefore, one megabyte is one million bytes o ...
s, a larger keyboard, built-in speech synthesis, built-in UCSD Pascal
UCSD Pascal is a Pascal programming language system that runs on the UCSD p-System, a portable, highly machine-independent operating system. UCSD Pascal was first released in 1977. It was developed at the University of California, San Diego (UCS ...
operating environment, and the full 16-bit data bus available on the expansion port. It was abandoned in the prototype stage. The Multi Emulator Super System
Multi Emulator Super System (MESS) is an emulator for various consoles and computer systems, based on the MAME core. It used to be a standalone program (which has since been discontinued), but is now integrated into MAME (which is actively dev ...
is capable of running what are believed to be the system's ROMs.
Legacy
The Tomy Tutor
The Tomy Tutor, originally sold in Japan as the and in the UK as the Grandstand Tutor, is a home computer produced by the Japanese toymaker Tomy. It is architecturally similar, but not identical, to the TI-99/4A, and uses a similar Texas Instrum ...
and its sibling systems are Japanese computers similar in architecture and firmware to the 99/8. Unlike the 99/8, it was released commercially, but sold poorly outside Japan. Portions of the operating system and BASIC code are similar to the 99/8.
Until 2006, there was an annual Chicago TI Faire where people celebrated the TI-99 family of computers.
Post-TI development
The Myarc Geneve 9640
The Geneve 9640 is an enhanced TI-99/4A clone. It was sold by the company Myarc as a card to fit into the Texas Instruments TI Peripheral Expansion System. Released in 1987, it is in many ways similar to the earlier TI-99/8, which was in prototype ...
is an enhanced TI-99/4A clone built by Myarc as a card to fit into the TI Peripheral Expansion System. It uses an IBM PC/XT detached keyboard. Released in 1987, it is similar to the unreleased TI-99/8 system. It includes a 12 MHz TMS9995 processor, enhanced graphics with 80-column text mode, 16-bit wide RAM, MDOS, and is compatible with nearly all TI software and slot-mounted hardware. A toggle switch slows the computer to the speed of the original.
The Second Generation CPU card (SGCPU) was released by the System 99 User Group in 1996 as a card to be installed in the PEB.
In 2004, a Universal Serial Bus card and Advanced Technology Attachment
Parallel ATA (PATA), originally , also known as IDE, is a standard interface designed for IBM PC-compatible computers. It was first developed by Western Digital and Compaq in 1986 for compatible hard drives and CD or DVD drives. The connection ...
controller for IDE hard disk
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnet ...
s for the PEB were released.
A range of plug-in cartridge boards have been developed, allowing software projects to be distributed on cartridge.
The Phoenix G2, was designed in 2010 by Gary Smith, a member of TI-User Group UK. It uses two FPGAs to emulate the entire architecture of the Myarc Geneve 9640 and the TMS9995 microprocessor. It incorporates an SD card reader, Ethernet, VGA
Video Graphics Array (VGA) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in the PC industry within three years. The term can now ...
output, and 64 MB RAM.
An FPGA-based TMS9918 compatible graphics chip, called the F18A, is a drop-in replacement for the original 9918 VDP, but features VGA output, bypassing the TMS9918A's native composite output, and contains other enhancements such as removal of the restriction of 4 sprites per scan line.
See also
* Texas Instruments Compact Computer 40
The Compact Computer 40 or CC-40 is a portable computer developed by Texas Instruments. It started development in 1981, and was released in March 1983 for US$249. The CC-40 has a single-line 31 character LCD display, weighs 600 grams (22 ounce ...
, a small portable computer introduced in 1983
* Texas Instruments Professional Computer
The Texas Instruments Professional Computer (abbreviated TIPC or TI PC) and the Texas Instruments Professional Portable Computer (TIPPC) are personal computers produced by Texas Instruments that were both released on January 31, 1983, and discont ...
(TIPC or TI PC), a personal computer that used the DOS operating system but was not fully compatible with the IBM PC (1983 – 1985)
* Texas Instruments Professional Portable Computer, a contemporaneous portable version of the TI Professional Computer
References
External links
Ninerpedia
wiki devoted to the TI-99 series
1979 TI-99/4
The TI-99/4A Home Computer Page
{{DEFAULTSORT:Texas Instruments Ti-99 4a
Products introduced in 1981
Home computers
16-bit computers