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The DAI personal computer is an early
home computer from the
Belgian
Belgian may refer to:
* Something of, or related to, Belgium
* Belgians, people from Belgium or of Belgian descent
* Languages of Belgium, languages spoken in Belgium, such as Dutch, French, and German
*Ancient Belgian language, an extinct languag ...
company ''
Data Applications International''. The DAI came to market in 1980. It provided many pioneering features such as high resolution color graphics, a maths co-processor, and a pre-compiling BASIC interpreter. However, it never became a commercial success.
History
The computer was initially designed by DAI for the
UK subsidiary of
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 globa ...
for use with the
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 ...
televisions used in Britain. TI
US did not want to build a PAL version of their
TI-99/4A
The TI-99/4 and TI-99/4A are home computers released by Texas Instruments in 1979 and 1981, respectively. Based on the Texas Instruments TMS9900 microprocessor originally used in minicomputers, the TI-99/4 was the first 16-bit home computer. ...
home computer, although they subsequently authorized one after they saw the DAI.
[Yet another computer museum](_blank)
/ref>
The Dutch educational TV broadcast company Teleac wanted to use the DAI to teach computing, some years before the BBC #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
's similar initiative using the
BBC Micro
The British Broadcasting Corporation Microcomputer System, or BBC Micro, is a series of microcomputers and associated peripherals designed and built by Acorn Computers in the 1980s for the BBC Computer Literacy Project. Designed with an emphas ...
. However, they chose the
Exidy Sorcerer
The Sorcerer is a home computer system released in 1978 by the video game company Exidy. Based on the Zilog Z80 and the general layout of the emerging S-100 standard, the Sorcerer was comparatively advanced when released, especially when compar ...
instead, because the DAI was not completely ready.
Main technical specifications
The DAI was based on a very early 8-bit
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 circ ...
, the
Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...
8080 A, a CPU that was more advanced than the prior
8008
The Intel 8008 ("''eight-thousand-eight''" or "''eighty-oh-eight''") is an early byte-oriented microprocessor designed by Computer Terminal Corporation (CTC), implemented and manufactured by Intel, and introduced in April 1972. It is an 8-bit ...
. It contained on a
single printed circuit board all the needed circuitry, some 120 individual ICs. The futuristic-looking white enclosure also held a high quality keyboard, which was uncommon for the time. As a
computer display
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 ...
, any
TV could be used. The DAI could display text and high resolution color pictures and contained a memory controller that enabled it to use up to of
DRAM. This memory was divided in three regions (memory banks) that could contain either 4K or 16K memory chips. By using memory map switching, a total of 72kB of memory was addressable. The DAI also had five programmable interval 64µ - 16ms interval timers that could generate interrupts. The built-in interrupt handler chip could also handle two external interrupt inputs and the interrupts of two serial RS232 UARTS. The DAI featured a DAI/Indata
DCE parallel I/O bus for parallel high speed I/O. The DAI also had 3 sound generators and 1 noise generator, and was capable of generating stereo sound.
Graphics capabilities with 48k RAM installed allowed up to 528 x 240 pixels in 4 out of 16 color palette in 4 successive blobs, leaving 16k programming space. The graphics modes were controlled by a device called Programmable Graphics Generator, implementing several techniques:
* decoupling physical scan lines from the 'logical' lines. The repeat count of physical scan lines could be 0 to 15 per line (Due to interlacing a physical scan was two pixels high),
* configurable horizontal resolution per line,
* using indexed colors,
* limit modifying the color palette to one color per line.
In 4 color mode, per logical line one foreground and one background color could be selected, so each line element or logical pixel could be represented by one bit.
In 16 color mode, the color palette was inherited from the previous line. only one of the four usable colors could be changed.
These graphical limitations were handled by
BASIC "so the user didn't notice his feet were tied together".
BASIC allowed only the whole screen in one mode, but
poking directly in memory allowed mixed resolution lines. The whole PGG was implemented with two
PROMs
The BBC Proms or Proms, formally named the Henry Wood Promenade Concerts Presented by the BBC, is an eight-week summer season of daily orchestral classical music concerts and other events held annually, predominantly in the Royal Albert Hal ...
and standard
TTL
TTL may refer to:
Photography
* Through-the-lens metering, a camera feature
* Zenit TTL, an SLR film camera named for its TTL metering capability
Technology
* Time to live, a computer data lifespan-limiting mechanism
* Transistor–transistor lo ...
logic. The scheme predated the
Amiga HAM mode by half a decade.
The
BASIC interpreter was remarkably fast for the time because it pre-compiled to an internal byte-code, unlike the
Microsoft
Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washin ...
BASIC interpreter which most other systems of the time used. DAI variables could be up to 14 characters long. The internal byte code used pointers to a variable look up table at the bottom of the code, which made the code extremely compact, despite long variable names.
This technique was rare (only other known examples are the
ABC 80
The ABC 80 (Advanced BASIC Computer 80) was a personal computer engineered by the Swedish corporation Dataindustrier AB (DIAB) and manufactured by Luxor in Motala, Sweden in the late 1970s and early 1980s. It was introduced on the market in August ...
and
BK-0010), and is remarkably similar to that now used for Java.
To enhance the mathematical abilities of BASIC, (and assembler programs) an
AMD
Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...
AM9511 floating point co-processor (compatible with the Intel 8231) could be added.
The first working example was produced in less than 3 months, by 3 people, one of whom was taping up the circuit board layout. All 64K of assembler was the work of one man David Collier, and all the hardware design the work of another David,
David Lockey. The original decision to use the 8080A 1 MHz processor (already in use by DAI on other products) was forced by the timescale, which itself was dictated by a desire to show the machine to a TI USA board meeting. In the end, only a flight on a Concorde got the machine there on time. However, the slow CPU dictated a huge amount of work on the pre-compiling BASIC and the option for hardware-assisted floating point which might not have been required if the newer Z80 had been chosen.
The decision to design the PC to use any old off-the shelf cassette tape recorder made the load and save speeds slow. The need to keep the end-user cost down dictated the need for extra complexity to output a TV signal capable of working with a domestic TV. When TI finally did put the 99/4 onto the European market a few months later, it was initially sold only in a pair with an American NTSC TV because it could not drive European PAL and SECAM sets.
Further technical details
*
CPU:
Intel 8080A at 2 MHz
* Memory: a maximum of 48 kB dynamic RAM, 24 kB
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
* ...
and 256 Bytes of static RAM (stack RAM)
* Keyboard: 56 Keys
* Video interface:
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 ...
compatible UHF CH 36 color-TV (antenna) output signal with audio
** Text mode: 60 characters × 24 lines (66 characters per line supported)
** Graphics modes: Low - 88 x 65 pixels; Medium - 176 x 130 pixels; High - pixels; Very high -
pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device.
In most digital display devices, pixels are the ...
s (non-square)
** available colors: 4 or 16 colors (16 color mode was actually 4 color palette)
* Sound generation: 3 frequency generators + 1 noise generator (General Instrument AY-3-8910?)
* Game controllers: 2 input interfaces for paddles or joysticks (DIY). Each can control three 0-5V inputs and a switch.
* Storage: 2 separate audio-cassette interfaces, using a cable for data INPUT/OUTPUT and START/STOP switch, (600
Baud)
* Alternative main storage systems:
**Memocom MDCR-D, Mini Digital Cassette Recorder (which used Philips
minicassettes)
**Two 5.25 inch floppy disk drives, 2 x 180K (which enabled the use of
CP/M).
* Compatible with optional
card rack, the ("
DAI Real World Card System"), control system.
* I/O Connectors:
** Serial port RS-232, DB-25 female.
** 2 audio-cassette ports, 2 x 6 pin DIN female.
** Parallel port DCE-Bus, DAI proprietary 3 x 8 bit parallel port, 36 pin DIL male.
** 2
Paddle
A paddle is a handheld tool with an elongated handle and a flat, widened distal end (i.e. the ''blade''), used as a lever to apply force onto the bladed end. It most commonly describes a completely handheld tool used to propel a human-powered w ...
interfaces, 2 x 6 pin DIN female.
** Stereo audio output, 6 pin DIN female.
** UHF video and audio output, RCA (cinch) female.
** AC power input, with voltage selector 220-110 volt, figure 8 shape AC power 2 pins male.
* System software:
**a
machine code monitor
A machine code monitor ( machine language monitor) is software that allows a user to enter commands to view and change memory locations on a computer, with options to load and save memory contents from/to secondary storage. Some full-featured m ...
with the following commands:
***LOOK
***DISPLAY
***GO
***FILL
***SUBSTITUTE
***MOVE
***EXAMINE
***EXAMINE REGISTERS
***VECTOR EXAMINE
***VECTOR EXAMINE BYTES
***READ
***WRITE
** a built in
DAI BASIC interpreter.
* the system was also supported with an 8080-
Assembler
Assembler may refer to:
Arts and media
* Nobukazu Takemura, avant-garde electronic musician, stage name Assembler
* Assemblers, a fictional race in the ''Star Wars'' universe
* Assemblers, an alternative name of the superhero group Champions of ...
.
* miscellaneous: a true
random number generator
Random number generation is a process by which, often by means of a random number generator (RNG), a sequence of numbers or symbols that cannot be reasonably predicted better than by random chance is generated. This means that the particular outc ...
implemented in hardware.
DAI the company
Data Applications International (DAI) was a company from the end of the 70s to the early 80s based at Dreve de Renards 6, Brussels that was specialized in creating "Real World Cards", computer peripheral cards based on their own proprietary
DCEbus, which in essence consists of three groups of eight I/O lines (coming from an
Intel 8255
The Intel 8255 (or i8255) Programmable Peripheral Interface (PPI) chip was developed and manufactured by Intel in the first half of the 1970s for the Intel 8080 microprocessor. The 8255 provides 24 parallel input/output lines with a variety of pr ...
) . These were
Eurocard compatible cards in a
19-inch rack
A 19-inch rack is a standardized frame or enclosure for mounting multiple electronic equipment modules. Each module has a front panel that is wide. The 19 inch dimension includes the edges or "ears" that protrude from each side of the equ ...
. Most cards were also based on a single Intel 8255 chip.
Around 1977 they designed the DAI Personal Computer. On May 6, 1982 the company went bankrupt.
DAI info
/ref>
The Indata company continued manufacturing DAI computer until 1984.
References
{{reflist
Home computers
Z80-based home computers
TI-99/4A