TRS-80 Model 100 line

The TRS-80 Model 100 portable computer was introduced in 1983. It was made by Kyocera, and originally sold in Japan as the Kyotronic 85. Although a slow seller for Kyocera, the rights to the machine were purchased by Tandy Corporation, and the computer was sold through Radio Shack stores in the United States and Canada as well as affiliated dealers in other countries, becoming one of the company's most popular models, with over 6,000,000 units sold worldwide. The Olivetti M-10 and the NEC PC-8201 and PC-8300 were also built on the same Kyocera platform, with some design and hardware differences.

The TRS-80 Model 100 was one of the first-ever notebook computers. It was originally marketed as a Micro Executive Work Station (MEWS), although the term did not catch on and was eventually dropped.

Specifications

• Processor: Eight-bit Intel 80C85, CMOS, 2.4 MHz
• Memory: 32K ROM, 8, 16, 24, or 32K static RAM. Machines with less than 32K could be expanded in 8K increments of plug-in static RAM modules.
• Display: Eight lines, forty characters LCD with 240 by 64 pixel addressable graphics. The screen was not backlit.
• Peripherals: The basic package included: Built-in 300 baud modem (North American versions), parallel printer port, serial communication port (shared by internal modem), bar-code reader input, cassette audio tape, real-time clock.
• Dimensions: 300 by 215 mm by 50 mm, mass about with batteries

Power supply: Four penlight (AA) cells, or external power adapter 6V (>180 mA, tip negative configuration)

The 8K and 24K versions sold for USD$1099 and USD$1399 respectively.

The Model 100 was promoted as being able to run up to 20 hours and maintain memory up to 30 days on a set of four alkaline AA batteries.

The Tandy Portable Disk Drive (TPDD), a serial device capable of storing 100 KB of data on a 3.5 inch diskette was also available. A second version, the TPDD2, could store up to 200 KB, as it used double sided disks.

A disk-video interface expansion box was released in 1984, with 5-1/4 inch disk drives and a CRT video adapter. This allowed the Model 100 to display 40 or 80 column video on an external television set or video monitor.

A bar code reader wand was also offered.

ROM firmware

When first switched on, the Model 100 displays a menu of applications and files and the date and time. The ROM firmware based system boots instantly, which compares very favourably to disk-based computers. Not only is the machine ready to use immediately on power-up, but it will also continue running, from the same point, the program that was running when the unit was powered off. Cursor keys are used to navigate the menu and select one of the internal or added application programs, or any data file to be worked upon.

The 32 kilobyte read-only memory of the Model 100 contains the N82 version of the Microsoft BASIC 80 programming language. This is similar to other Microsoft BASICs of the time and includes good support for the hardware features of the machine: pixel addressing of the display, support for the internal modem and serial port, monophonic sound, access to tape files, and support for the real-time clock and the bar code reader. Unlike other Microsoft BASIC interpreters of the time, the default for floating point numbers is double-precision.

The ROM also contains a terminal program, TELCOM; an address/phone book organizer, ADDRSS; a to-do list organizer, SCHEDL; and a simple text editor, TEXT. The TELCOM program allows automation of a login sequence to a remote system under control of the BASIC interpreter.

Invisible files in the system RAM named "Hayashi" and "Suzuki" commemorate the names of designers Junji Hayashi and Jey Suzuki. Another invisible deleted file named "RickY" refers to Rick Yamashita. The Model 100 firmware was the last Microsoft product that Bill Gates developed personally, along with Suzuki. According to Gates, "part of my nostalgia about this machine is this was the last machine where I wrote a very high percentage of the code in the product".

Added applications and data files are stored in the internal battery-backed RAM; these can be loaded from and stored to an audio cassette tape recorder or external floppy disk drive. Optional ROMs can be installed in the Model 100, providing a range of customized application software.

Applications

When introduced, the portability and simplicity of the Model 100 made it attractive to journalists, who could type about 11 pages of text and then transmit it using the built-in modem and TELCOM program for electronic editing and production. Writers continue to use the Model 100 for first drafts. Other professionals use it to take notes when away from the office. The computer is silent when it operates. The keyboard is superior to most others currently on the market. It runs for 20 hours on 4 readily available and easily replaceable AA batteries. Data is protected by a built-in rechargeable battery. There is no boot up routine; the Model 100 operates as soon as you flip the on switch and select an application. There are several simple programs available on the Internet for transferring Model 100 files to a modern personal computer.

The Model 100 was also used in industrial applications as a programming terminal for configuration of control systems and instruments.

Third-party peripherals for the Model 100 extended its battery life and file storage capacity. Software was designed, and is still available, to extend the display capabilities and to provide more advanced word-processing or calculation software than the supplied programs. To this day, hobbyists continue to design games, applications, and hardware for this device.

With few exceptions, no modern portable computer has the appearance, or some would argue utility, of the Model 100 line. Modern portable computers (laptops) are larger, heavier, and have much shorter battery life than the Model 100. The closest modern successors include the Alphasmart Dana and the Quickpad Pro. These similar modern "slabtop" units typically are targeted at the education market, although they are often used by writers and mobile professionals.

Although much larger, the Model 100 actually bears a close resemblance to modern PDAs. Its TEXT program is similar to the Memo program found on PalmOne products, and ADDRSS and SCHEDL are essentially simplified versions of Contacts, Tasks and Calendar. The Model 100 has the additional advantage of a full size keyboard, a built-in modem and BASIC programming language. By including BASIC, the Model 100's designers made it possible for users to design additional applications.

Because of its adaptability and features as well as its current relative affordability, the Model 100 and its progeny (Model 102/200/600) enjoy a near cult status among its supporters. Club 100 and Bitchin100 are the center of the Model 100 universe. Model 100 enthusiasts continue to explore this early computer, trading information, participating in contests and designing new applications with existing and newly designed hardware and software.

Peers and successors

Kyocera sold essentially the same notebook computer as what it manufactured for Radio Shack. Other similar machines were sold by NEC (the PC-8201 with expanded memory) and Olivetti (M-10).

The Model 102 was a successor to the Model 100 but thinner. All Model 102 systems had at least 24 KB RAM. The Model 200 was introduced in 1985 as the successor to the 102. The Model 200 came with 24 KB RAM and can be expanded to 72 KB (3 banks of 24 KB), a flip-up 16 line by 40 column display, and a spreadsheet (Multiplan) included. The Model 200 also includes DTMF tone-dialing for the internal modem (older models only supported pulse dialing).

The EPSON HX-20 used a much smaller LCD display and had an internal cassette tape drive for program and file storage.

Systems of about the same size and form-factor as the Model 100, aimed at journalists, were sold by companies such as Teleram and Grid Systems; the latter was later acquired by Tandy.

The Cambridge Z88 was developed by Sir Clive Sinclair and was similar in form and functionality to the Model 100 but had greater expansion capacity.

The Bondwell 2 was a CP/M laptop in a similar form factor to the Model 200.

Data General developed the Data General-One (DG-1), a much more powerful (but more costly) MS-DOS portable computer with disk drives and a full-sized LCD screen. Radio Shack later introduced the LT1400, which was also a diskette-based MS-DOS system.

As of 2008, the system closest to a Model 100 still in production was the AlphaSmart Dana, a Palm OS device with a full-sized keyboard.

Trivia

As with other home computers of the era, a vast collection of PEEK and POKE locations were collected by avid hobbyists.

The Model 100 keyboard had 56 keys, eight programmable function keys, and four dedicated command keys, but neither a backslash () nor a pipe (|) key.

The Model 100 ROM has a Y2K bug; the century displayed on the main menu was hard-coded as "19XX". Workarounds exist for this problem.

Aftermarket products

• DLPilot - allows a PalmOS PDA with a serial port to emulate a Tandy TPDD drive, providing affordable, compact, and portable storage that is easily synced to a desktop computer
• ReMem - replaces all the memory in the laptop, allowing the use of 4MB of flash ROM and 2MB of SRAM
• REX - memory subsystem that fits in the option ROM socket
• Tandy 200 RAM Module - adds 2 banks of 24kb to a T200

References

• TRS-80 Model 100 Owner's Manual, (1983) Tandy Corporation, Fort Worth Texas
• BYTE Magazine April 1984, advertisement for Disk-Video Interface
• BYTE Magazine May 1985, advertisement for Model 200
• Rich Malloy, "Little Big Computer: The TRS 80 Model 100 Portable Computer", BYTE magazine, May 1983 pg. 14
• Stan Wszola, "NEC PC 8201 Portable Computer", BYTE magazine June 1983, pg. 282

External links

• Club 100
• a photograph of the TRS-80 Model 100 and closely related machines