Tandy TRS-80 Model 1
The TRS-80 Model 1 from RadioShack was , along with the Apple II and the Commodore PET 2001, one of the first home computers to be produced in significant numbers as finished copies. He came in 1977 to the market and was a Z80 - CPU from Zilog equipped that ran with 1.77 MHz clock frequency. The TRS-80 had particularly good sales successes in the USA . The new price in Germany was 3,000 DM.
At first it was only delivered with 4 KiB RAM (which could be upgraded to 16 KiB within the keyboard). The operating system stored in ROM in the form of the BIOS and the integrated BASIC were typical of the time . With the help of an "Expansion Interface" it could be expanded by a further 32 KiB RAM, a floppy disk controller for up to four 5.25 "drives as well as a serial and a parallel interface .
Graphics and equipment
The TRS-80 Model 1 had a graphic resolution of 128 × 48 pixels . This resolution was generated by the character cells on the screen, which were divided into 6 small blocks. In reality, it was a block graphic made up of special characters from the 64 × 16 line text mode , which had to be cleverly used. Any commercially available television set could be used as a screen via an RF modulator that had to be purchased , provided that high image quality was not important; originally a monitor was supplied that was available with a black and white or black and green display.
There was a Level I of Model 1 with 4 KiB ROM and a simplified BASIC, which was written by the TRS designer Steven Leininger . This was based on the Palo Alto Tiny BASIC, which is under public domain , and a Level II with 12 KiB ROM and a BASIC that already corresponded to the Microsoft standard that was popular at the time (and was also licensed from there) and was based on disk commands using the expansion interface expanded.
One of the cult programs of that time, despite the block graphics, was the game Dancing Demon , in which a cute little devil danced on the screen and the mono sound of the cassette recorder interface was supposed to entertain the user.
In the original version, one bit per byte was saved on the screen memory for cost reasons . As a result, the TRS-80 was not able to display lowercase letters . If you wanted to achieve this, you had to add a memory module afterwards, which then made bit number 6 available in every byte of the screen memory.
Compact cassette and floppy disk
At first the data was still saved on compact cassette , but very soon various disk operating systems ( DOS ) were added. The best known were the TRSDOS from Tandy and the very advanced NewDos 80 from Apparat. TRSDOS and NewDos 80 initially supported 35 Track Single Sided Single Density 87.5 KiB disks in 5.25 "format, later with newer drives and controllers also 40 and 80 Track Double Sided / Double Density, so that 720 KiB could be stored.
Even back then, the NewDos 80 made unusual projects possible in the home computer sector, such as remote control of a Tandy using a modem or acoustic coupler via the public telephone network from another computer. The first mailboxes or BBS 'emerged in which users could post contributions on virtual bulletin boards. There were already catalogs with dozens of office programs from various manufacturers such as Text , Calculation , Fibu , Lager etc. for the TRS 80 at the beginning of the 1980s , but this changed from around 1982 after the introduction of the IBM PC with MS-DOS and thereafter various compatibles done quickly.
Compatible models and replicas
Based on the TRS-80 Model 1, there were also models III and 4 (in this notation; the first and fourth models were provided with an Arabic number in the catalog), as well as the Portable 4P. All of them were offered with 15/32/48 or 64 KiB RAM, an integrated b / w monitor and the option of installing up to two 5.25-inch floppy disk drives and, due to the price range and equipment, counted among the office computers.
The Video Genie was a replica of the Model 1 produced by EACA in Hong Kong and sold in Germany by Trommeschläger Computer Service . The computer was sold as System 80 in Australia , as PMC-80/81 in the USA , as HT-1080Z and in Hungary distributed in South Africa as TRZ-80 . The replica was practically 100% compatible and only had a few differences in hardware control and a different bus interface . In contrast to the TRS-80 Model 1, the Video Genie was never delivered with a monitor, but instead had an integrated video modulator and a cassette recorder. The video Genie II was marketed as a professional computer. The cassette drive was replaced by a numeric keypad. The Color Genie included an extension for color graphics, but, unlike the TRS Color Computer, was still compatible with the TRS-80 Model 1.
Another replica of the TRS-80 Model 1 was sold under the name KOMTEK in Germany, there are various private replicas based on modified Z80 single-board computers.
The Polish company Mera-Elzab built the Meritum computer series in the early 1980s (first Meritum I and since 1985 Meritum II), which was based on the TRS-80. The main difference to the TRS-80 was that only components made in the Eastern Bloc (including the U880D ) were used in production. This clone of a TRS-80 quickly became very popular in Poland and had a decisive influence on computerization in schools, but later lost to Western competitors Atari , Commodore and Sinclair .
Various replicas were also made in Brazil - e.g. B. the Dismac series D8000 / D8001 / D8002 (Model 1 compatible), the Digitus DGT-100 and DGT-1000 and the successful CP300 and CP500 (Model III) from Prológica .
TRS-80 family
Until the appearance of the first PC-compatible Tandy 2000, the brand TRS-80 was used for all computer products from Tandy. This included both other Z80-based computers with similarities to the TRS-80 Model 1, as well as completely different, mostly purchased series, such as the handheld computer Model 100 ( Kyocera ) or the pocket computers PC-1 to PC-8 ( Sharp / Casio ).
Model II was not compatible with Model 1, but allowed the use of CP / M instead of TRS-Dos without any changes to software or hardware and had the 8 "drives that were prevalent in the professional sector at the time. Model 12 was an extended version of the Model II. The Model 16 was a model 12 expanded with a 6 MHz 68000 processor. The Z80 served as an I / O processor . With TRS-Xenix, an OEM version of Microsoft Xenix , the Model 16B (8 MHz 68,000) and the successor Model 6000 was the best-selling Unix computer in the USA with 40,000 units in 1984. Model II was used, for example, by Bavarian savings banks for calculating loans.
Another computer not related to the Model 1 was the Tandy TRS-80 Color Computer (CoCo) and the TRS-80 M10, developed jointly with Motorola on the basis of the Motorola 6809 .
criticism
Radio Shack's marketing policy at the time was questionable, for example, when they placed these very expensive office computers (Model II over 10,000 DM) next to plush toys with built-in radios in their catalog. In this way, Tandy / Radio Shack disqualified itself from professional buyers. In Europe, the devices were sold in their own TANDY stores, similar to those at Media Markt today, alongside hi-fi and electronics. There were also various computer franchisers and pure Tandy computer stores.
The construction of the power supply units offered for the German market was also questionable. These were based on the power supplies for the US market and were poorly adapted, as a result of which they produced considerable amounts of waste heat. Some users operated their computers to reduce waste heat and protect the hardware - via regulating transformers - with a mains voltage of approx. 180 V (around 20% below the then mains voltage of 220 V) without any problems.
You have to give TANDY (Radio Shack) the fact that at the end of the 1970s they set up a functioning sales organization with their own branches in Europe, thus making it possible for people without access to the computer scene to make purchases. Unfortunately, for tax reasons, German sales were discontinued again from 1985, although most branches were still generating high profits.
Community
Already at that time, user groups came together intensively, even when no inexpensive modems or acoustic couplers were available (or those that were permitted in Germany) . There were larger well-known user magazines called 80 micro and 80-NW , which later became part of the national 80-US .
Emulators
There is also the option of emulating the TRS-80 on modern computers. Vavasour.ca is an example here. There emulators for almost all RadioShack computers are provided.
Web links
- www.trs-80.com English-language TRS-80 site with emulators for the PC
- New Zealand side to the TRS-80
- Information in the 8-bit museum about the TRS-80
- RadioShack emulators
Individual evidence
- ↑ TRS-80.org: [1] (accessed on April 26, 2010)
- ↑ Bartimo, Jim: Tandy Revamps Product Line . In: InfoWorld , March 11, 1985, pp. 28-29. Retrieved January 21, 2015.