Welcome back to part 2 of my SepTandy Spectacular. In the last post I went over the history of Radio Shack with how they started and met their demise. In this post I'm going to jump back to 1977 and talk about their first computer, The TRS-80.
The Radio Shack TRS80 Model 1 (1977).
When it comes to the history of personal computers, Tandy Radio Shack is one of those companies that doesn't get much credit for the role they played. So in this post we'll be diving in to this humble machine and see what made it different as well as what it contributed to in in the history of computers.
It all began in 1975 when Micro Instrumentation and Telemetry Systems (or MITS), introduced what is considered by many to be the world's first personal computer the Altair 8800.
The Altair 8800 (1975).
The Altair was a very simple machine; There was no display or keyboard, programs had to be entered in binary with the toggle switches on the front. It came with no memory and extra memory was expensive. It was also mostly sold in a kit that the user would have to assemble themselves.
Despite these setbacks, it became very popular with hobbyists. From Microsoft founders Bill Gates and Paul Allen, to Apple Founders Steve Jobs and Steve Wozniak. One of the buyers of the Altair 8800 was Don French.
Don French.
French had joined Tandy in 1973 as a product buyer and already had various kit computers in his office for managing product lines. Seeing the potential for selling a computer of their own, he pitched the idea to John Roach, The vice president of manufacturing, Who was intrigued with the idea. After a visit to National Semiconductor in 1976, The two men learned about Homebrew Computer Club member Steve Leininger and his expertise on the SC/MP microprocessor.
Steve Leininger.
The two met Leininger working part-time at Byte Shop and hired him for his technical and retail experience, in June 1976. Originally, the company wanted it in a kit, but Leininger persuaded the others that a preassembled computer would be better since it could be approachable to everyone.
While French, Roach, and Leininger saw the potential, the other employees in the company did not. By that point, Radio Shack had 11 million customers at over 3,000 stores, it had a large base of potential customers who would consider buying a computer. However, Any computer would have to be priced in the hundreds of dollars compared to the $29.95 median price of an item sold at Radio Shack. Not only that, but Radio Shack was very conservative when it came to selecting products. They rarely took big risks that resulted big losses. Taking the chance to sell a computer would definitely qualify as a risk.
But Charles Tandy, the head of Tandy Corporation, thought that Radio Shack needed to develop some new products. After hearing about French’s idea, he gave his approval for it to be further developed in In December, 1976.
The first design had several cost saving measures; such as only uppercase character generation, a membrane keyboard, and no video monitor which would sell for $199, But Leininger persuaded Roach and French to include a better keyboard; it, a monitor, data cassette storage, and other features.
After another couple months of development, The TRS-80 (an abbreviation for Tandy Radio Shack, Z80), was released on August 3, 1977 at a price of US$399 for just the base computer itself, or US$599 with a 12" monitor and a Radio Shack tape recorder.
Initially Tandy weren't expecting sharp sales and only made 3500 machines enough so the computer could be used in the stores for inventory if none were sold. However customers proved Tandy wrong as over 10,000 units were sold in the first month and a half on sale and by 1980, Tandy had beat the sales of the Apple II and the Commodore PET combined.
Along with the Apple II and the Commodore PET, The TRS-80 became part of the so-called 1977 Trinity of computers.
The machine itself is very simple. Its an all in one unit where the mainboard and keyboard are combined into one, which became a design trend in the 8-bit microcomputer era, although the TRS-80 does have a separate power supply.
The TRS-80 base computer itself.
The early units where referred to as Level I units, which refers to the type of BAISC built into the machine. These only came with 4K of RAM and a 4K ROM containing the OS and the BASIC programing language itself. Later on, there was a Level II basic sold both as an upgrade and as pre installed units with a numeric keypad and 16K of RAM.
On the back there are sockets for a tape recorder, monochrome video out, the power plug, the power button and on the very end the expansion interface.
The latter did cause grief for some users as the pins on the expansion interface card edge could oxidize and cause a spontaneous reboot. As a result later on there were gold plated contacts that you could solder on to fix this issue. This was one of many hardware flaws with the TRS-80, We'll get into some more of them later.
As for video output, The TRS-80 had the optional 12 inch monitor, Which was really a rebadged RCA KCS 172 tv set. It displayed text in Black and white, with the standard P4 phosphor used in black-and white televisions, which gave the white a faint blue color. Many people complained about the video quality, so Third Party green and amber filters and replacement tubes to reduce eye fatigue were popular aftermarket items, and later monitors came with a green-on-black display.
The original TRS-80 Monitor.
Powering up the machine, you get dropped into Level 1 basic where you're greeted with a READY prompt. here you can type in various BASIC programs of various complexity levels. In this example i'll type in the obligatory HELLO WORLD! program.
As previously mentioned The original TRS-80 came with Level 1 BASIC which is pretty...well...basic. The dialect was based on “Palo Alto Tiny BASIC”, a 2K version of Tiny BASIC written by Dr. Li-Chen Wang in the May 1976 issue of Dr. Dobb’s Journal.
The first page for the listing of Palo Alto Tiny BASIC in the May 1976 issue of Dr. Dobb’s Journal.
Because Dr. Li Chen-Wang placed his BASIC in the public domain, Steve Leininger, was able to use it as a starting point. He added floating point math, cassette, keyboard, and video routines, doubling the size of the original code to 4K.
A funny story during development of the TRS-80, When French, Roach, and Leininger showed their prototype, running a simple tax-accounting program, to Charles Tandy in February, 1977, Tandy typed in a $150,000 figure as his salary but the computer's implementation of Tiny BASIC could not handle the number and it crashed! This resulted in the support for floating-point math.
Level I BASIC allowed for three types of variables: 26 numeric variables, labeled A through Z, 2 string variables, labeled A$ and B$, and 1 array variable, labeled A(x) (with x used as the index). The error messages are somewhat unusual, there are three error messages: HOW?, WHAT?, and SORRY. HOW?, is for arithmetic errors such as division by zero, WHAT? is for syntax errors, and "SORRY" for out of memory errors.
The later Level II BASIC was written by Microsoft and was essentually a stripped down version of extended BASIC. It included new commands such as the IF, THEN, and ELSE statements as well as unique commands such as, such as SET, RESET, POINT, and INKEY$.
This did lead to a problem with compatibility between BASICs on other computers because the commands and syntax was different that made typing in programs from books and magazines, (The only place you could find software for your computer.), somewhat difficult unless you knew what to change to get it to work (However with Level II this wasn't much of an issue).
Speaking of software, for storage the TRS-80 had cassette port that would allow you to load and save programs on cassette tape. Yes, Cassette tape storage was a thing at the time!
%20(1).png)
This was mostly due to the low price and you could use any tape recorder or tapes at home. It worked by sending the data as a series of pulses and noise, kind of like a dial up modem, but its on a cassette instead of a modem. The downsides to using cassettes was that they were slow and often unreliable.
Radio Shack added a cassette interface as well, and unlike the Apple II, The TRS-80 had a plug for the remote socket that would allow the computer to control the tone levels for you which made cassette storage much more reliable. As previously mentioned, Radio Shack did provide a cassette recorder as an optional extra. That tape recorder was the CTR-41, which is your typical "shoebox" style tape recorder of the time.
.png)
The CTR-41 Tape recorder.
To load programs you type in CLOAD, press play on the tape (or just hit return if you have the remote jack connected), wait for the program to finish loading, then type RUN. Later with Level II BASIC, you could also load in Machine Language programs by typing SYSTEM, typing the first letter of the program on the tape to search for it, wait for the program to finish loading, then type a / and hit return.
Cassettes were really the only storage medium the TRS-80 had at launch. However, it wouldn't be long until floppy disk capability became available. Starting in 1978, with the introduction of the Expansion Interface.
Unlike other 8080 and Z80-based computers, The TRS-80 didn't use the S-100 bus. Instead, it used the proprietary Expansion Interface box, which fits under the video monitor and served as its base. It offered features such as a slot to install an optional daughterboard for an RS-232 serial interface, an expansion port extension, Centronics parallel port for a printer, a floppy disk controller, an added cassette connector, and a spot to install an extra 16 or 32 KB of RAM. Other peripherals included modems (Which allowed for the access of the MicroNET service (Which eventually became the consumer version of Compuserve), and eventually ARCNET, (The first widely available networking system for microcomputers, from Datapoint Corporation.), speech synthesizers, joystick interfaces, Lightpens, hard drives, and even a device called the VOXBOX which allowed for voice recognition, Probably making the TRS-80 the first personal computer capable of voice recognition!
As for the hardware of the computer itself, It uses a Zilog Z80 processor clocked at 1.78 MHz (later models shipped with a Z80A clocked at 4 MHz), 4K of RAM initially and later 16K of RAM as previously said, 1K of video RAM, 4K of ROM (Later 12K with Level II BASIC).
.png)
Due to the limited video memory, the graphics are displayed at a text resolution of 64 columns by 16 rows. This was somewhat of an unusual choice of text resolution at the time as most machines had 40x25 or 80x25. There is no lowercase characters, (though there are modifications that you could do to get lower case), and no graphics modes, however there are some predefined block characters in the character set that could be used to make pseudo graphics.
This did give the TRS-80 an advantage over its competitors. Because unlike the Apple II and the Commodore PET, which initially had 40 columns of text, The TRS-80's 64 columns of text made working with text based programs much easier and could be used for business applications like spreadsheets or word processing. In fact later models were marketed as business computers and with some modification, the TRS-80 could even run the #1 operating system of its day, Digital Researches CP/M, which was incredibly popular with businesses.
There was no sound for the computer, initially but there were various ways to get sound. one way was that since the machine produced so much radio interference, sound effects could be generated by placing an AM radio near the computer. Another way was to output data to the cassette port and hook up a speaker to the microphone port on the cassette recorder to produce square wave tones. There were even sound cards made such as Orchestra 85.
As for the software you can run on it, Well, The TRS-80 proved to be popular with and had plenty of software to use in schools and some businesses, But when it came to things like games, it was somewhat of a downer. Compared to the Apple II, the TRS-80's blocky graphics and crude sound were widely considered limited. However, that didn't stop programmers from making games for the system, mostly making unlicensed versions of arcade games like Namco's Galaxian, Atari's Asteroids, and Namco/Midway's Pac-Man. The only company to have officially licensed ports for the TRS-80 was Sega, who made ports of Frogger and Zaxxon through Cornsoft. Broderbund software, (known for hit Apple II games like Choplifter, Lode Runner, Karateka, and Prince of Persia), originally began by publishing TRS-80 software. But by 1983, they pulled out of the market because cofounder Doug Carlston realized that the TRS-80 had a terrible market due to the closed distribution networks. One of the most popular types of games for the TRS-80 were text adventures. Adventure International's Scott Adams text adventures began on the TRS-80, and Infocom released games such as Zork and The Hitchhiker's Guide to the Galaxy for the system.
While the TRS-80 was a massive success, It did have a lot of criticisms, mostly stemming from the build quality and its various hardware flaws. Along with the previously mentioned expansion interface and rebadged tv monitor, and RF interference, The TRS-80's keyboard originally used Hi-Tek High Profile mechanical switches. Due to the Unsealed nature of the switches; dirt, cigarette smoke, and other types of debris could enter the key switches, causing electrical noise that caused "keyboard bounce", resulting in multiple letters being typed per keystroke.
The keyboard bounce only occurs with the Level II BASIC firmware; Level I BASIC had a "debounce" delay in the keyboard driver to avoid the noisy switch contacts. Tandy's KBFIX utility, later models, the last Model I firmware, and most third-party operating systems also implement the software fix. Tandy eventually changed the keyboards to an Alps Electric design with sealed SKCC Cream switches. The Alps keyboard was also available as an upgrade for the Model I for $79.
All of these criticisms toward the machines poor quality hardware and software eventually led to the system being nicknamed the Trash-80, which TRS-80 fans hate to this day.
The TRS-80 was discontinued in 1981, due to stricter FCC regulations on radio-frequency interference to nearby electronic devices. However the story of the TRS-80 didn't end there, The TRS-80 Model II was launched just 2 years after the first machine in October 1979, and targeted at the small-business market. It was an all-in-one unit with enhanced features such as a Z80a running at 4 MHz, a double-density 8" drive (expandable to up to four drives), 32K of RAM, upgradable to 64K (and later upgradable to 256K), a detachable 76 key keyboard, with HOLD, ESC, BREAK, CTRL, CAPS, REPEAT, F1, and F2 keys, a built in parallel port, two RS-232 ports, a built-in 12" screen, capable of displaying 80 columns by 24 lines, with uppercase, lowercase, and 32 “business graphics” characters and, four plug-in card slots. However, aside from simple BASIC programs, the Model II was incompatible the older model (Retroactively named the Model I). it also lacked cassette interface.
The TRS80 Model 2 (1979).
The Model II was succeeded by the compatible TRS-80 Model 12, Model 16, Model 16B, and the Tandy 6000.
.png)
Left to right: The TRS-80 Model 16 (1982), The TRS-80 Model 12 (1983), The TRS-80 Model 16B (1984), and The Tandy 6000 (1985).
The Model III was introduced in 1980, that was not only backwards compatible with the Model I, but also had a number of improvements such as: an enhanced character set with built-in lowercase characters, a better keyboard with repeating keys, a real-time clock, 1500-baud cassette interface, a faster Z80 processor (clocked at 2.03 MHz), and an all-in-one enclosure requiring fewer cables.
The TRS-80 Model III (1980).
The Model III was succeeded by the Model IIII in 1983 and was the last TRS-80 computer produced, being discontinued in 1991. It had a faster Z80A CPU (At 4Mhz), a larger video display 80 columns x 24 rows with reverse video, a larger keyboard, an internal speaker, 64K of RAM that could be upgraded to 128K of bank-switched RAM, and the option for a high resolution graphics card yielding 640 × 240 pixels. The Model 4 is fully compatible with Model III and finally was able to run CP/M software out of the box.
The TRS-80 Model IIII (1983).
There was also a portable version called the Model 4P. It has all the features of the desktop Model 4 except for the ability to add two outboard floppy disk drives and the interface for cassette tape storage (audio sent to the cassette port in Model III mode goes to the internal speaker).
The TRS-80 Model 4P (1983).
The TRS-80 models can be seen in many movies and tv shows such as The A-Team, Airplane 2, and Miami Vice. In fact the TRS-80 Model 1 happens to be the very first personal computer to be shown in a film! In the sports movie North Dallas Forty (1979) B.A. uses team statistics stored on a Tandy TRS-80 to remind himself of Phil's performance tendencies.
The TRS-80 Model 1 in North Dallas Forty (1979).
Also The TRS-80 Model II was the computer General Computer Corporation used to develop their first arcade conversion kits starting with Super Missile Attack and eventually Ms. Pac-Man.
So in conclusion I hope I gave you a good look at The TRS-80 line. An innovative beginner which was not only the the beginning of personal computers for Radio Shack, but for a lot of people who still hold it dear to their hearts to this day. In the next entry we go forward in time to the 80s, where we met Radio Shack's first color computer.
No comments:
Post a Comment