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From its introduction in 1980, the TRS-80 Color Computer proved to be a remarkably expandable machine. While the original Color Computer 1 (1980) was initially offered with as little as 4K of RAM, enthusiasts and third-party manufacturers quickly developed upgrades that pushed its capabilities well beyond the original specifications.

The CoCo 1 and CoCo 2 (1983) shared the Motorola 6809E processor architecture, with memory upgrades progressing from 4K to 16K, 16K to 32K, and eventually 64K. More ambitious expansions explored 128K and 256K configurations, while bubble memory offered an entirely different approach to nonvolatile storage rather than conventional RAM expansion.

The introduction of the Color Computer 3 in 1986 marked a significant advancement. Equipped with 128K of RAM as standard and designed to support expansion to 512K, the CoCo 3 provided a more capable foundation for sophisticated software and operating systems. Later developments, including Cloud-9's DAT board, which helped to enable 2MB upgrades, and the Protector+, pushed the machine's capabilities even further.

Memory wasn't the only component receiving attention. Across the Color Computer family, enthusiasts also explored replacing the original Motorola 6809E processor with the enhanced Hitachi 63C09E, which offered additional instructions, native-mode operation, and improved performance in software designed to take advantage of its capabilities.

This section follows the evolution of memory and processor upgrades across all three Color Computer generations, from the earliest CoCo 1 RAM expansions and CoCo 2 enhancements to the advanced memory-management and CPU upgrades developed for the CoCo 3. Together, these products demonstrate how a computer family introduced in 1980 continues to evolve decades after its commercial life ended.

For the entry point into this section, we'll get the Color Computer's only widely adopted CPU replacement out of the way — the Hitachi HD6309, most commonly the externally clocked HD63C09EP.

Unlike a conventional speed upgrade, the 6309 offered something more interesting: an expanded instruction set and additional registers that gave programmers new ways to push the CoCo beyond its original capabilities.

Which RAM Upgrade?

From it's release configuration of a 4k machine, the CoCo (and it's users) were clamoring for an upgrade. Two things stood in the way of that: the skills and memory price/availability. That could be contrused as three things, but oh well.

The first upgrade paths were thru knowledgable usergroup members, and info shared in the early days of computer magazines. It wasn't long before Radio Shack started offering memory upgrades thru their computer centers

Do We Really Need More Memory?

In an article published in the January 1982 issue of The Rainbow, Al Morgan questioned the Color Computer community's seemingly endless appetite for additional RAM, arguing that programmers could accomplish considerably more through efficient, carefully structured code. His argument certainly had merit. Good programming practices were especially important on machines with limited resources.

However, the suggestion that better programming could eliminate the need for additional memory was shortsighted. More RAM wasn't simply an excuse for inefficient programming; it made larger programs, more sophisticated applications, improved graphics, and entirely new capabilities possible.

Consider games such as Donkey King and Time Bandit. Neither could have delivered its gameplay and graphical complexity within the original 4K memory configuration. Nor could more sophisticated operating systems such as OS-9 or FLEX have operated within those constraints. These weren't examples of programmers being wasteful with memory; they were examples of software whose capabilities demanded resources beyond those available in the original machine.

In retrospect, the argument seems remarkably similar to those who once believed nobody would ever need more than 10 megabytes of hard-disk storage. Such predictions tend to overlook a fundamental characteristic of computing: as hardware capabilities expand, software developers discover entirely new things to accomplish with them.

Perhaps the greatest irony is the article's unusual placement in The Rainbow: it began on page 19 and concluded on page 16. An article about making better use of limited memory that apparently traveled backward through the magazine to finish its argument.

Almost a lesson in recursion (yes, I was reading an issue of Rainbow recently, duh!).

Efficient programming is always desirable. But no amount of clever coding can make four kilobytes accommodate software that fundamentally requires substantially more memory.

The Early Days: User Groups, Magazines, and a Soldering Iron

In the Color Computer's earliest days, expanding its memory wasn't necessarily as simple as purchasing an upgrade kit and following the instructions. For many owners, the first source of information wasn't Radio Shack at all. It was the growing community of enthusiasts exchanging discoveries through local computer clubs, user groups, newsletters, and magazines.

These early publications became an invaluable resource. Readers shared circuit modifications, memory-chip substitutions, wiring diagrams, and programming techniques that pushed the Color Computer beyond its original specifications. Some modifications were relatively straightforward; others required considerable electronics knowledge, steady hands, and a willingness to take a soldering iron to a perfectly good computer.

One of the earlier guides for a TRS-80 Color Computer memory upgrades came from the January 1981 issue of '68 Micro Journal, and then updated with 32k info in the May 1981 issue:

"Now for some good points. The TRS80c• can be easily upgraded to 16K by the changing of two Jumpers from the 4K to 16K positions, on the circuit board, end the swapping of the 4K RAM chips for 4116 dynamic RAM chips. That's all there is to It!

Going to 32K Memory. As mentioned In Byte . March Issue, page 124, RAM chips may be piggybacked to get 32K of RAM capacity.

1. Use the 'Diagnostic' pack to do the "Long RAM test on 16K of memory. Note: The "Q"uick and "L"ong diagnostic tests are "dumb" and will only test a maximum of 16K.

2. Then repeat the "L"ong RAM test on a second set of eight 4116 type RAM chips.

3. Now piggyback one set of eight chips on top of the other. Push them together only far enough for one chip pin to contact the other. Observe pin #1 orientation on both chips. With a small soldering Iron quickly tack solder each of the pins together (EXCEPT for pin #4
of the top chip which gets carefully bent out to the side.)

4. Install the eight chip pairs back Into the sockets. Observe orientation.

5. Use some small solid wire (#30 wire wrap) to connect together all of the ^4 pins of the top chips. Use a minute amount of solder or wire wrap.

6. Then use another longer piece of the same type wire to connect this series of #4 pins to pin #35 of the SAM chip (6883). Just push the (uninsulated) end of the wire Into the SAM chip socket. No soldering necessary on the main board Itself.

That's It - you now have a 32K TRS-80C!!"

Another particularly early example appeared in the July 1981 issue of Color Computer News. In an article titled 32K RAM for the Color Computer, Bob Lentz described expanding a 16K machine to 32K by piggybacking eight additional 4116 dynamic RAM chips onto the existing memory devices.

The procedure involved connecting the additional chips through the Color Computer's 6883 Synchronous Address Multiplexer (SAM). Lentz also described optional modifications to the video circuitry that would allow the display to occupy the newly available upper memory bank.

This was more than a simple parts list. The article provided instructions and circuit diagrams, giving technically inclined owners enough information to attempt the modification themselves.

By February 1982, the possibilities had become even more interesting.

In Color Computer News, Frank Hogg published an article titled 32K RAM for FREE!!!, describing how certain 32K Color Computers already contained 64K memory chips, even though the computer could access only half their capacity.

Hogg explained how modifications to the computer's memory-selection circuitry could make the additional RAM available. His article included circuit diagrams, testing procedures, and a discussion of what owners might actually do with the extra memory.

Among the possibilities was running the FLEX operating system, with OS-9 support also under development. These were compelling reasons to expand memory that had little to do with inefficient programming.

The importance of these early articles shouldn't be underestimated. They demonstrated that the Color Computer's limitations weren't necessarily permanent and that knowledgeable enthusiasts could sometimes overcome them without waiting for an official manufacturer-supported solution.

Of course, not everyone possessed the necessary technical skills, equipment, or confidence to perform such modifications. As demand for additional memory grew, an opportunity emerged for companies willing to package these discoveries into installation kits, plug-in expansion boards, and professional upgrade services.

What began as information shared among enthusiasts would soon become a substantial aftermarket industry.

Radio Shack's Official Memory Upgrades

When Radio Shack first introduced the TRS-80 Color Computer, its catalog offered two configurations:

• 4K Color Computer (26-3001) — $399.00

• 16K Color Computer with Extended BASIC (26-3002) — $599.00

The $200 difference was substantial, particularly for a home computer marketed toward families and first-time computer owners. For many buyers, the less expensive 4K model offered an affordable entry into computing, with the possibility of expanding its capabilities later.

Owners who initially purchased a 4K Color Computer could upgrade to 16K using Radio Shack's 16K Memory Conversion Add-on (26-3015), priced at $119.00. Extended Color BASIC, which required at least 16K of RAM, was available separately for $99.00.

Together, these upgrades represented an additional $218.00 investment. A customer purchasing the original $399 machine and upgrading it later would have spent $617.00, compared with $599.00 for the factory-equipped 16K Extended BASIC model, excluding any installation charges or other expenses.

Radio Shack expanded its offerings in the 1982 catalog, introducing the 32K Extended BASIC Color Computer (26-3003) for $749.00. The company also offered a 32K RAM Kit (26-3017) for $149.00, providing an upgrade path for existing owners.

By the 1983 catalog, the 16K Color Computer had become the standard entry-level configuration, priced at $399.95. In just a few years, what had originally been a significant memory upgrade was now the starting point for new buyers.

Radio Shack also marketed the Color Computer in several complete system packages. These ranged from the Home Entertainment and Control System, priced at $702.80, to the considerably more ambitious 32K 2-Disk Professional Color System, costing $2,550.95.

These configurations demonstrated how far the Color Computer could be expanded beyond its original home-computing role. They also illustrated the considerable financial investment required to build a fully equipped system using Radio Shack's own hardware.

For many owners, those prices provided another incentive to investigate alternatives. Independent manufacturers began offering less expensive memory upgrades, while others developed installation methods that avoided the soldering and circuit modifications associated with early do-it-yourself projects.

What began as a technical challenge shared among enthusiasts was rapidly becoming a competitive aftermarket industry.

This ad appeared in the January 1982 issue of Rainbow and Color Computer News magazines, and continued for several months A full page ad in April and subsequent of 1982 in Rainbow, and later Hot CoCo, with the memory upgrade section RAM SLAM offered the following:

In a January 1985 Rainbow ad, DSL offered a 128k upgrade for 64k CoCo for $99, including the RAM. In the June 1985 issue of Hot CoCo, this expansion kit was reviewed along side a competitive kit by  Dynamic Electronics.

JARB Software & Hardware's 16K-to-32K kit, appears repeatedly, starting in January 1983, in several different magazines; this one was in Rain of that month and year.. The advertisement describes a kit containing eight 200 ns 4116 chips, piggyback sockets, a SAM socket, bus wire, and a 32K RAM button. That makes it more than a simple chip replacement.

JARB's January advertisement also specifies a $49.95 price and says minimal soldering is required, with an estimated 30-minute installation.

Spectral Associates – Supercharger (1982)

Spectral Associates of Tacoma, Washington, offered the Supercharger, advertised as early as August 1982 for $39.95, as a way to access the TRS-80 Color Computer's full 64K RAM capacity without modifying the motherboard.

The Supercharger was specifically designed for 32K Color Computers equipped with Revision E motherboards. Unlike earlier motherboard revisions, Revision E machines used 64K memory chips configured to operate as 32K. If all 64K of the installed memory was functional, the Supercharger could enable access to the otherwise unused upper 32K. It could not repair defective memory or provide additional RAM.

The device plugged into the cartridge port and included a pass-through connector for ROM cartridges and disk controllers. Although it eliminated the need for permanent hardware modifications, a September 1983 review in Color Computer News documented compatibility problems with certain 64K programs, including Telewriter 64.

The Supercharger represented an innovative early approach to memory expansion, allowing owners of compatible Revision E machines to unlock memory already present in their computers.

References:

• The Rainbow, August 1982 — Spectral Associates Supercharger advertisement.

• William F. Estep, “Supercharger,” Color Computer News, September 1983, pp. 70–72. View PDF

Dynamic Electronics first appeared (advertising RAM upgrades, anyway) in the April 1983 issue of Rainbow:

Dynamic offered a complete range of solderless RAM upgrades, through 64k rather than just IC chips. Their RAM upgrades even received a new product announcement in Color Computer New in the December 1983 issue, on page 139.

Green Mountain Micro, operated by Dennis Bathory Kitsz in Roxbury, Vermont, offered a variety of hardware upgrades and expansion products for the TRS-80 Color Computer during the early 1980s.

Among its offerings was a 64K memory upgrade kit priced at $49.95, allowing owners to expand their existing Color Computers. The company also marketed a RAM/ROM Pack, available assembled for $29.95 or as a kit for $19.95, providing additional memory capabilities through the cartridge interface.

Green Mountain Micro continued advertising its 64K upgrade kits into 1985. By October of that year, the price had dropped to $25, or $30 with an optional memory tester.

The company's products provided Color Computer owners with affordable alternatives to factory memory upgrades, while its selection of assembled hardware and do-it-yourself kits appealed to users with different levels of technical experience.

(The bubble memory will not be covered here, as the original CCN article is above.)

RGS Micro Inc. – 128K RAM Card (1984)

RGS Micro Inc. offered a 128K RAM Card for the TRS-80 Color Computer and Color Computer 2, advertised in the October 1984 issue of The Rainbow for $149.95.

Designed for existing 64K machines, the internally mounted expansion board added another 64K of memory using eight 4164 RAM chips. A programmable array logic (PAL) chip controlled memory banking, allowing the additional memory to be accessed as two 32K banks or as an alternate 64K bank. The card was promoted particularly for OS-9 users.

Although advertised as easy to install, a December 1984 discussion in The Rainbow documented installation difficulties involving soldered motherboard components and physical clearance in certain CoCo 2 models.

The RGS card was an early commercial attempt to expand the Color Computer beyond its standard 64K memory limit, providing additional bank-switched RAM for applications that could take advantage of it.

References:

• The Rainbow, October 1984 — RGS Micro 128K RAM Card advertisement.

• The Rainbow, December 1984, p. 288 — Contemporary discussion of the RGS expansion board and installation considerations.

• The Rainbow, March 1985 — Later advertisement mentioning bundled Kdos software.

Spectrum Projects – Super RAM (1986)

Introduced in 1986, Super RAM was Spectrum Projects' answer to the memory-expansion limitations of the TRS-80 Color Computer 2. Unlike the company's earlier Thunder RAM, which required internal installation and was incompatible with the CoCo 2, Super RAM housed its additional memory and supporting circuitry in an external, shielded metal enclosure.

Super RAM was manufactured by Disto and distributed by Spectrum Projects, as confirmed by the June 1986 review in The Rainbow.

Designed to operate through a Radio Shack Multi-Pak Interface, Super RAM was offered in 256K and 512K versions, priced at $129.95 and $169.95, respectively. Its primary purpose was to provide a high-speed RAM disk, allowing programs and data to be accessed without the delays associated with floppy drives. An optional OS-9 driver was available for $24.95, with the 512K version particularly recommended for OS-9 users.

Spectrum Projects advertised compatibility with all CoCo 2 models, including the later 26-3127B and 26-3134A/B revisions. The company promoted Super RAM at the 1986 Palo Alto Rainbowfest and referenced an independent review in the June 1986 issue of The Rainbow.

Super RAM offered CoCo 2 owners a practical way to add substantial working storage without modifying the computer's motherboard, distinguishing it from conventional internal RAM upgrades.

References:

• The Rainbow, May 1986 — Spectrum Projects advertisement introducing Super RAM.

• The Rainbow, June 1986 — Super RAM review, identifying Disto as manufacturer.

• The Rainbow, July 1986 — Spectrum Projects advertisement detailing pricing, compatibility, and OS-9 support.

• The Rainbow, September 1986 — Spectrum Projects advertisement confirming specifications.

J&R Electronics – Banker II (1986)

Introduced in 1986, Banker II was J&R Electronics' follow-up to its original Banker memory expansion for the TRS-80 Color Computer 1 and 2. Developed by Jesse Jackson and Raymond Rowe of Columbia, Maryland, the system combined a revised memory-management board with a separate RAM expansion board, providing either 256K or 512K of bank-switched memory.

Banker II was designed for internal installation, with the memory-management board occupying the computer's SAM socket and the expansion board fitting beneath the keyboard. Installation was generally solderless, although certain CoCo 2 motherboard revisions required additional modifications. Both kit and fully assembled versions were offered.

Like its predecessor, Banker II included software to make practical use of memory beyond the CoCo's normal 64K address space. Applications included high-speed RAM disks, floppy-disk copying, printer spooling, memory testing, and expanded graphics storage. Programmable memory banking also allowed users to develop applications that accessed multiple 32K or 64K memory segments.

Banker II was reviewed by Jeffrey S. Parker in the April 1988 issue of The Rainbow. Parker tested the assembled 512K version, praising its flexibility, documentation, and software support, although he reported occasional operating problems that could not be consistently reproduced. The review listed prices of $39.95 for the kit and $169.95 for the fully assembled system.

Arriving during the transition to the CoCo 3, Banker II offered owners of earlier Color Computers a way to obtain substantial additional memory without replacing their existing machines.

References:

• The Rainbow, August 1986 — J&R Electronics advertisement.

• The Rainbow, October 1986 — J&R Electronics advertisement.

• The Rainbow, April 1988, pp. 133–134 — Jeffrey S. Parker, “Banker II — Expand and Manage CoCo 2 Memory.”

PBJ Inc. — 512K Memory Upgrade / 512CE (1987)

By early 1987, PBJ Inc. was manufacturing a 512K memory expansion for the Tandy Color Computer 3, offering an alternative to Radio Shack's official upgrade. The board expanded the computer's standard 128K of RAM to 512K and was marketed through several companies, including Spectrum Projects and Speech Systems, in addition to PBJ's own involvement with the product.

The expansion used sixteen socketed 41256 dynamic RAM chips, rated at 120 nanoseconds, mounted on an L-shaped, double-sided glass-epoxy circuit board. Measuring approximately 4½ by 2⅞ inches, the board connected to the CoCo 3's existing memory expansion sockets and used the computer's built-in GIME memory-management hardware.

The PBJ upgrade was reviewed by Jerry Semones in the March 1987 issue of The Rainbow, under the title “CoCo III 512K Upgrade: Money-Saving Modification.” The review identified PBJ as the manufacturer and Spectrum Projects of Howard Beach, New York, as the distributor. Spectrum offered the board for $139.95 with memory chips or $99.95 without chips, plus $3 shipping and handling.

During the same period, Speech Systems of Batavia, Illinois, marketed a 512K expansion under the name 512K Turbo RAM. Its accompanying installation documentation specifically identified the hardware as the PBJ 512CE Memory Upgrade Board, establishing the connection between Speech Systems' product and PBJ's design.

Speech Systems advertised Turbo RAM in March 1987 at an introductory price of $119.95, reduced from $149.95, while an unpopulated board was available for $69.95. Its package included a memory-test program, GIME technical information, and MUSICA RAM Disk software. Speech Systems also advertised a two-year warranty.

References:

• Jerry Semones — “CoCo III 512K Upgrade: Money-Saving Modification,” The Rainbow, March 1987, p. 145.

• Speech Systems — “Turbo Charge Your CoCo 3,” advertisement, The Rainbow, March 1987.

• Speech Systems — 512K Turbo RAM documentation, incorporating PBJ 512CE installation instructions.

• PBJ Inc. — 512CE Memory Upgrade Board installation documentation.

Performance Peripherals — CoCo 3 512K Turbo RAM Board (1987)

By late 1987, Performance Peripherals of Mira Loma, California, was offering its own 512K memory expansion for the TRS-80 Color Computer 3. Marketed as the CoCo 3 Turbo RAM Board, the upgrade expanded the computer's original 128K of RAM to 512K, providing an economical alternative to Radio Shack's factory expansion kit.

The board appeared in the November 1987 issue of The Rainbow, where it was listed at $79.95, including a memory-test program. A February 1988 advertisement offered the fully populated board for the same price, while an unpopulated version was available for $29.95. This allowed owners to purchase the circuit board separately and install their own memory chips.

The Performance Peripherals expansion used sixteen socketed 256K × 1-bit dynamic RAM chips, with the company specifying 120-nanosecond memory. Installation involved removing the CoCo 3's four original RAM chips and connecting the expansion board to the motherboard's existing memory connections. The supplied instructions also required modifying two motherboard capacitors, C65 and C66, by disconnecting one lead or removing them entirely. Although advertised as a solderless installation, this capacitor modification made the procedure somewhat more involved than simply plugging in a replacement board.

Performance Peripherals emphasized the quality of its construction, using double-wipe IC sockets and individual decoupling capacitors for the memory chips. The company advertised its boards as individually tested and burned in before shipment, and backed them with a one-year warranty and a 30-day money-back guarantee.

Additional software was available to take advantage of the expanded memory, including RAM-disk and print-spooler utilities. A dedicated 512K memory-test program could exercise the expanded RAM and help identify defective memory chips.

The Performance Peripherals board received favorable attention in Martin H. Goodman's article “Upgrading CoCo's Memory,” published in the March 1989 issue of The Rainbow. Goodman examined the board's construction, including its sixteen 0.33 µF decoupling capacitors and double-wipe sockets, and reported successfully using one in his own development system. The complete article is available in our Magazine Upgrade Articles section.

With its competitive pricing, socketed memory, and supporting utilities, the Performance Peripherals Turbo RAM Board represented another practical route to the CoCo 3's supported 512K configuration.

References:

• The Rainbow, November 1987 — “Received and Certified,” Performance Peripherals CoCo 3 Turbo RAM Board listing.

• The Rainbow, February 1988, p. 95 — Performance Peripherals advertisement.

• Performance Peripherals — RAM Board Installation, two-page installation guide.

• Martin H. Goodman — “Upgrading CoCo's Memory,” The Rainbow, March 1989.

• Performance Peripherals — 512K CoCo 3 Memory Test and 512K utility software.

Microcom Software — 512K and 1MB Memory Upgrades (1987–1988)

Microcom Software, located in Fairport, New York, was among the companies advertising memory expansion products for the Tandy Color Computer 3 during the late 1980s. By November 1987, the company was offering a 512K memory upgrade, and advertisements appearing in the February 1988 issue of The Rainbow promoted both a 512K expansion board and a more ambitious upgrade capable of increasing the CoCo 3's memory to 1MB.

The 512K Memory & 1MB Upgrades

Microcom's 512K upgrade was advertised as a fully assembled and tested expansion board using 120-nanosecond DRAM chips. The company emphasized its solderless installation and claimed that the board's design provided firm electrical contact while positioning the memory chips on top to minimize potential heat-related problems.

The February 1988 advertising described installation as taking approximately two minutes, with illustrated instructions supplied. One advertisement listed the complete upgrade at $79.95, with an unpopulated board available for $44.95. Another advertised a complete, tested upgrade for $99, with a bare board priced at $39.95..

The February 1988 Microcom included a 1MB memory expansion for the CoCo 3, offering twice the capacity of the more conventional 512K upgrades. Unlike the solderless 512K board, the 1MB expansion required an existing 512K CoCo 3 and some soldering experience. The advertisement stated that the kit included the additional 512K of memory and the necessary hardware, along with OS-9 drivers written by Kevin Darling.

Two configurations were offered:

• Zero-K kit — $119: Hardware kit without the additional memory chips.
• Complete 1MB kit — $159: Hardware and memory required for the expansion.

Sources and references:

• The Rainbow, November 1987 — Microcom Software 512K upgrade advertisement.
• The Rainbow, February 1988 — Microcom Software 512K upgrade and 1MB expansion advertisements.
• Microcom Software, P.O. Box 214, Fairport, New York 14450.

DISTO 1MB Memory Upgrade — 1989–1990

By the late 1980s, the Tandy Color Computer 3's 512K memory ceiling was becoming increasingly restrictive, particularly for users running OS-9 Level II and other memory-intensive applications. Although numerous manufacturers had introduced upgrades to expand the CoCo 3 from its original 128K to 512K, moving beyond that limit presented a considerably more difficult engineering challenge.

DISTO Super Products, developed by Tony DiStefano and distributed through CRC Computers in Quebec, Canada, was among the companies tackling this limitation. Its 1MB Memory Upgrade extended the CoCo 3's memory capacity to a full megabyte while allowing owners to retain their existing 512K expansion boards.

A prototype was reportedly demonstrated at the Somerset RainbowFest in October 1989, and the upgrade was described as a new product in early 1990. The original DISTO installation manual provides additional chronological evidence, with schematics dated September 29, 1989.

A Different Approach to Memory Expansion

Unlike conventional 512K upgrades, which simply replaced or supplemented the CoCo 3's original RAM, the DISTO 1MB system required additional circuitry to extend the computer's memory-addressing capabilities.

The upgrade consisted of two principal components: a special 512K memory expansion board and a separate Data Address Translation (DAT) control board.

The memory board installed into the CoCo 3's existing RAM expansion connectors after the original memory chips had been removed. Female headers on its upper surface allowed the owner's existing 512K expansion board to be installed directly above it, creating a stacked arrangement providing a total of 1MB of RAM.

This design offered an important advantage: owners who had already invested in a 512K upgrade did not have to discard their existing hardware. DISTO's installation manual specifically described compatibility with existing 512K memory cards.

The additional memory board contained sixteen 256K × 1 DRAM chips, providing another 512K of physical memory. It also incorporated supporting circuitry, including memory-decoding logic and voltage regulation.

The DAT Control Board

The second component was a separate DAT board, responsible for extending the CoCo 3's memory-addressing capabilities beyond the GIME chip's normal 512K limit.

The CoCo 3's memory-management hardware normally provided sixteen DAT registers, each selecting an 8K physical memory block from a total of 64 blocks. This arrangement allowed access to 512K of physical RAM.

DISTO extended this arrangement to 128 physical blocks, permitting the processor to access 1MB of memory through the existing 64K address space.

The DAT board employed additional digital logic, including four 74LS670 register chips, to provide the expanded address selection. The original manual also describes a mechanism associated with address $FF9B that allowed the system to select which 512K region supplied video memory.

This additional circuitry was essential. Simply installing more RAM would not have allowed the original GIME to address memory beyond its intended range.

Installation and Hardware Modifications

Installing the DISTO 1MB upgrade was considerably more involved than fitting a conventional 512K memory board.

The special memory board was installed first, followed by the owner's existing 512K expansion board. Additional wiring connected the memory expansion hardware to the DAT circuitry and the GIME.

The DAT board interfaced directly with the CoCo 3's 6809 processor through a specially formed 40-pin adapter. Rather than using a conventional replacement CPU socket, the adapter's pins were soldered directly to the processor's legs.

The installation instructions called for soldering all 40 connections and checking continuity before proceeding. This made the installation a more demanding undertaking, requiring careful workmanship to avoid shorts or damaged components.

The resulting assembly was distinctive: two memory boards stacked above the motherboard, a separate CPU-connected DAT board, and additional interconnecting wiring.

Although complex by later standards, the arrangement allowed the CoCo 3 to retain much of its original architecture while accessing twice the memory previously available through conventional 512K upgrades.

Software Support and Practical Benefits

Expanded hardware addressing was only part of the challenge. Operating systems and applications also needed software capable of recognizing and using the additional memory.

The DISTO installation manual credits Kevin Darling with developing OS-9 drivers and patches for the 1MB expansion.

OS-9 Level II was particularly well suited to taking advantage of additional physical memory because its memory-management architecture could allocate and manage multiple processes within the expanded address space.

For BASIC and other software designed around the original CoCo 3 memory configuration, the benefits depended on whether the software had been written or modified to recognize the additional memory.

The upgrade therefore represented more than a simple increase in RAM capacity. It combined hardware address expansion with operating-system support to make memory beyond 512K practically usable.

Surviving Hardware and Documentation

Original DISTO 1MB hardware survives, including examples of both the memory expansion board and the separate DAT control board.

The photographed memory board carries the marking COCO3 1M MEM, while the reverse identifies the PCB as PRESTIGE-2-0. The accompanying control board is marked DISTO, COCO 1 MEG, V 1.0, Made in Canada, and PRESTIGE-2-0.

The significance of the PRESTIGE-2-0 marking has not been independently established. It may represent a board designation or production revision, but the available evidence does not justify identifying it as a separate manufacturer.

The surviving installation manual provides unusually detailed documentation, including installation procedures, a theory of operation, and schematics dated September 29, 1989.

Together, the original documentation and surviving hardware provide a valuable record of one of the more ambitious commercial memory expansions developed for the Color Computer 3.

Historical Significance

The DISTO 1MB Memory Upgrade represented an important step beyond the CoCo 3's original memory architecture.

Tony DiStefano's design demonstrated how additional memory-addressing circuitry could extend the machine beyond the GIME's conventional 512K limit, while preserving compatibility with existing 512K memory expansion hardware.

Its installation was undeniably complicated, involving stacked memory boards, additional control logic, soldered CPU connections, and interconnecting wiring. Nevertheless, the design helped demonstrate that the CoCo 3's memory capacity was not necessarily limited to what Radio Shack had originally provided.

Later memory expansions would offer larger capacities and more compact hardware arrangements, but DISTO's 1MB upgrade remains a notable example of the ingenuity employed by third-party developers to extend the useful life and capabilities of the Color Computer.

Sources and references

• DISTO 1 Meg Memory Upgrade Kit, original installation and technical manual, DISTO Super Products / CRC Computers Inc.; schematics dated September 29, 1989.

• Tandy's Little Wonder, historical references to the October 1989 prototype demonstration and early 1990 product introduction.

• Surviving DISTO 1MB memory expansion and DAT boards, photographed front and rear, including installation hardware.

DISTO 2MB Memory Upgrade — 1993

Following the development of its 1MB memory expansion in 1989–1990, DISTO Super Products introduced an even more ambitious upgrade for the Tandy Color Computer 3. Announced in 1993, the DISTO 2MB Memory Upgrade quadrupled the capacity of a conventionally expanded 512K CoCo 3 and represented a substantial redesign of Tony DiStefano's earlier memory-expansion hardware.

The new design abandoned the stacked memory boards used by the original 1MB upgrade in favor of two 1MB SIMM modules and a redesigned Data Address Translation (DAT) interface. Although the new hardware was considerably more compact, extending the CoCo 3's memory capacity to 2MB still required sophisticated additional circuitry to overcome the limitations of the machine's GIME chip.

The exact commercial introduction date has not been established. Contemporary historical references place DISTO's announcement in 1993, the same year The Rainbow ceased publication in May. Whether the upgrade became available before or after the magazine's final issue remains uncertain.

A New SIMM-Based Design

The DISTO 2MB upgrade consisted of two internal circuit boards: a memory expansion board and a separate DAT control board.

Unlike the earlier DISTO 1MB system, which accommodated an existing 512K expansion board, the 2MB upgrade replaced the computer's previous memory expansion hardware entirely.

The new memory board plugged into the CoCo 3's standard memory expansion connectors and carried two sockets for 1MB SIMMs. These modules provided the full 2MB of system memory without requiring an existing 512K upgrade.

The original installation manual specified 1MB × 8-bit DRAM SIMMs using 100-nanosecond or faster memory, and also supported compatible 1MB × 9-bit modules. In his technical paper, Inside DISTO's 2-Meg Kit, Tony DiStefano described testing several SIMM configurations, including two-, three-, eight-, and nine-chip modules.

Using readily available SIMM memory represented a significant improvement over the earlier arrangement of individual DRAM chips and stacked expansion boards. The new design also fit entirely inside the original CoCo 3 enclosure.

Extending the GIME's Memory Addressing

The CoCo 3's GIME chip normally provided sixteen DAT registers, allowing the processor to select 8K memory blocks from a maximum of 512K of physical RAM.

DISTO's 2MB upgrade extended this arrangement by adding two additional address-selection bits to each DAT entry. Instead of selecting among 64 physical memory blocks, the expanded circuitry permitted selection among 256 blocks of 8K, providing access to the full 2MB.

The additional address bits were maintained by circuitry on the DAT board, which interfaced with the CoCo 3's processor and memory-management signals.

Because the GIME itself could not read back these additional bits, software using the expanded memory had to maintain its own record of their settings. The original installation manual specifically cautioned programmers about this limitation.

Video memory required separate handling. DISTO provided an additional register at address $FF9B that allowed software to select one of four 512K regions for video display.

Although this permitted graphics and text screens to be placed within any of the four memory regions, the GIME could not automatically cross a 512K boundary during video access. Software therefore had to ensure that a display buffer remained within the selected region.

Solving the DRAM Refresh Problem

Memory addressing was only one of the challenges involved in expanding the CoCo 3 to 2MB.

The larger DRAM devices used by the SIMMs required different addressing and refresh behavior from the 256K DRAM chips originally supported by the GIME.

In Inside DISTO's 2-Meg Kit, Tony DiStefano explained that the design required additional circuitry to supply the higher memory-address bits and accommodate the SIMMs' refresh requirements.

The memory board therefore performed more than a simple electrical connection between the SIMMs and the motherboard. It incorporated logic to multiplex the additional address signals, generate the necessary timing, and provide suitable refresh cycles.

DiStefano's technical discussion describes the use of CAS-before-RAS refresh and additional circuitry to distinguish processor memory accesses from video accesses.

Much of the engineering effort involved reconstructing the timing relationships required by the GIME, particularly because several useful internal signals were not available directly from the chip's external pins.

This work illustrates why expanding the CoCo 3 beyond 512K was considerably more complicated than installing larger memory devices.

Installation and Hardware Requirements

Although the DISTO 2MB upgrade was physically neater than the earlier 1MB design, installation still required opening the computer and making electrical modifications.

The DAT board interfaced directly with the CoCo 3's 6809 processor.

For computers with a socketed CPU, the processor could be removed and installed in the socket on the DAT board. The DAT assembly was then connected to the original CPU socket using the supplied adapter.

For machines with a soldered CPU, the installation instructions described fitting a 40-pin socket over the existing processor and soldering each socket connection to the corresponding CPU leg.

Additional connections were required on the motherboard, including a jumper across resistor R22 and two signal wires connected to specified circuit points.

The memory board was installed in the original expansion connectors and linked to the DAT board through a six-pin cable.

Once installed, the supplied memory-test software could be used to verify operation and confirm that the full 2MB was accessible.

DISTO described the installation as an evening's work, although the original manual emphasized that good soldering experience was necessary.

OS-9 Support and Software Compatibility

As with DISTO's earlier 1MB expansion, OS-9 Level II was a principal beneficiary of the additional memory.

The upgrade included OS-9 drivers and patches that allowed the operating system to recognize and manage the full 2MB. The installation manual credited Kevin Darling with writing the supplied OS-9 software unless otherwise noted.

For users running multiple processes, RAMdisks, or memory-intensive applications, the additional capacity offered possibilities far beyond the CoCo 3's original configuration.

Software written for the standard 128K or 512K memory arrangement could continue operating, but it would not automatically take advantage of the additional memory. Applications required appropriate support to access physical memory beyond the original GIME addressing range.

The upgrade was therefore particularly attractive to OS-9 users and programmers interested in extending the CoCo 3's capabilities.

Documentation and Historical Significance

The DISTO 2MB upgrade is unusually well documented compared with many late-period Color Computer expansion products.

Its surviving installation manual provides hardware installation instructions, memory requirements, software considerations, and an explanation of the extended addressing arrangement.

Even more valuable is Tony DiStefano's technical paper, Inside DISTO's 2-Meg Kit, which documents the design's internal operation in considerable detail. The paper includes schematics, programmable logic information, and explanations of the memory-addressing and refresh circuitry.

These documents establish that the 2MB upgrade was not merely a larger version of DISTO's earlier 1MB product. It represented a substantial redesign, combining SIMM-based memory with new circuitry for addressing, timing, and refresh control.

The upgrade also demonstrated how far the CoCo 3 could be extended beyond Radio Shack's original specifications. A computer introduced with 128K of RAM could now accommodate sixteen times that amount, while retaining its original processor and GIME chip.

Although later memory expansions would provide still greater capacities and more compact implementations, the DISTO 2MB upgrade remains an important example of the technical ingenuity of the Color Computer's independent hardware developers.

It also stands as a fitting continuation of Tony DiStefano's work on memory and bus-addressing circuitry, extending the practical capabilities of the CoCo 3 well beyond its original design.

Sources and references

• DISTO Super Products, 2-Meg Memory Upgrade Kit, original installation and technical manual.

• Tony DiStefano, Inside DISTO's 2-Meg Kit, technical description, schematics, and programmable logic documentation.

• Tandy's Little Wonder, historical reference to DISTO's 1993 announcement of the 2MB upgrade.

Cloud-9 512K SIMM Memory Upgrade — Available by 2002

As the Color Computer entered the twenty-first century, owners continued to seek reliable ways to maintain and expand their aging machines. Although 512K memory upgrades had been available for the CoCo 3 since the late 1980s, many of the earlier expansion boards relied on individual 41256 DRAM chips that were becoming increasingly difficult to obtain.

Cloud-9, a company established in 1994 and associated with CoCo developers Mark Marlette and Boisy Pitre, offered a practical alternative with its 512K SIMM Memory Upgrade. Rather than using a collection of individual DRAM chips, the board employed two removable SIMM memory modules, making it easier to source replacement memory and maintain the upgrade.

The product was advertised on Cloud-9's website by 2002, although its original introduction date has not been established. Surviving examples include a board marked Rev. D 6/2003, while the original installation manual, Revision 1.2, is dated April 30, 2004.

Design and Features

The Cloud-9 upgrade expanded a standard 128K Color Computer 3 to 512K using two 256K SIMM modules.

Its distinctive stepped circuit board carried two SIMM sockets arranged side by side, along with the necessary connections to the CoCo 3 motherboard. The board installed directly into the computer's existing memory expansion connectors, eliminating the need for a separate external interface or extensive additional wiring.

Cloud-9 specified 120-nanosecond or faster SIMMs using eight or nine memory chips per module. Three-chip SIMMs were explicitly unsupported because their refresh requirements exceeded those provided by the original CoCo 3 hardware.

The use of removable SIMMs offered a practical advantage over conventional expansion boards populated with individual DRAM chips. Compatible memory modules could be replaced without desoldering individual devices, and the upgrade could be maintained using memory components that remained relatively common in the personal computer surplus market.

Cloud-9 promoted the board as a quality, cool-running memory upgrade, although the surviving documentation does not provide comparative power-consumption or temperature measurements.

Installation

Installation followed the general procedure used by many conventional CoCo 3 memory upgrades.

The computer's four original DRAM chips, identified as IC16 through IC19, were removed from the motherboard. Two small capacitors, C65 and C66, were also removed as specified in Cloud-9's instructions.

The new memory board was then installed into the existing expansion connectors, with J4, J5, and J6 aligning with CN4, CN5, and CN6 on the motherboard.

Because of the board's position above the keyboard connector, Cloud-9 recommended temporarily moving the keyboard forward while leaving its cable attached. This provided additional cable clearance during installation.

Once the board was seated and the keyboard reinstalled, the computer could be reassembled and tested.

The upgrade did not require additional CPU-mounted address-translation hardware, since its 512K capacity remained within the standard addressing capabilities of the CoCo 3's GIME chip.

Testing and Software Compatibility

Cloud-9 supplied a BASIC memory-testing utility named MTEST512, distributed on a 5¼-inch disk.

The utility could be launched with the command RUN "MTEST512" and performed repeated tests of the expanded memory until interrupted by the user.

Because the upgrade retained the CoCo 3's standard 512K memory organization, it was compatible with software designed to use conventional 512K expansion hardware.

This included applications and operating systems such as OS-9 Level II and NitrOS-9, which could benefit from the additional memory without requiring the specialized address-translation hardware associated with larger 1MB and 2MB expansions.

Pricing and Availability

Cloud-9 offered the upgrade both as an assembled product and as a kit for users comfortable assembling their own hardware.

A surviving 2002 website listing advertised the completed 512K SIMM upgrade for $35 plus shipping, while the kit version, supplied without memory, was priced at $20 plus shipping.

The kit included the printed circuit board and components needed to assemble the upgrade, with the purchaser providing the SIMM modules and assembly labor.

By 2007, an advertisement listed the assembled and tested version at $40, with the kit without memory priced at $25.

These prices made the Cloud-9 board an affordable option for enthusiasts maintaining or restoring Color Computer 3 systems many years after Radio Shack had discontinued the computer.

Surviving Hardware and Documentation

Original examples of the Cloud-9 SIMM upgrade can be identified by their distinctive stepped circuit board and two SIMM sockets.

One surviving board carries the silkscreen markings Cloud-9, 512K SIMM Memory, and Rev. D 6/2003, establishing a documented hardware revision from June 2003.

The original user manual, Revision 1.2, dated April 30, 2004, provides installation instructions, SIMM compatibility requirements, and information about the supplied memory-testing utility.

Together with Cloud-9's surviving website material and later advertising, these sources provide a useful record of the upgrade's design, pricing, and continued availability during the 2000s.

Historical Significance

Cloud-9's 512K SIMM upgrade was not intended to exceed the CoCo 3's established 512K memory limit. Instead, it addressed a different problem: keeping conventional memory expansion practical and affordable as the original hardware aged.

By replacing increasingly scarce individual DRAM chips with removable SIMM modules, Cloud-9 offered owners a convenient way to maintain and expand their machines without adopting the more complicated circuitry required by larger memory upgrades.

The product also reflected the changing nature of the Color Computer aftermarket. By the early 2000s, expansion hardware was no longer primarily about competing with new commercial computers. It was increasingly about preserving existing systems, improving reliability, and making replacement components easier to obtain.

Cloud-9 would later introduce its TRIAD 512K SRAM upgrade, which took a different approach by replacing conventional DRAM with lower-power static memory.

The earlier SIMM-based board remains a noteworthy example of how independent developers continued supporting and improving the Color Computer long after its commercial production had ended.

Sources and references

• Cloud-9, 512K SIMM Upgrade product webpage, 2002 archival capture.

• Cloud-9, 512K SIMM Upgrade User Manual, Revision 1.2, April 30, 2004.

• Cloud-9, 512K SIMM Upgrade product webpage, 2007 archival capture.

• Surviving Cloud-9 512K SIMM Memory circuit board, Revision D, June 2003.

• Tandy's Little Wonder, second edition, historical discussion of Cloud-9 hardware and CoCo expansion products.

Cloud-9 TRIAD 512K SRAM Memory Upgrade — 2013

In 2013, Cloud-9 introduced the TRIAD 512K SRAM Memory Upgrade for the Tandy Color Computer 3, offering a modern alternative to the conventional DRAM-based expansion boards that had been available since the late 1980s.

Unlike traditional 512K upgrades, including Cloud-9's own SIMM-based expansion introduced in 1997, TRIAD employed static RAM (SRAM) rather than dynamic RAM (DRAM). This eliminated the need for memory-refresh circuitry and substantially reduced the electrical power consumed by the expansion hardware.

Cloud-9 promoted TRIAD as a cooler-running, lower-power replacement for its earlier memory boards, emphasizing its compact dimensions and reduced demands on the CoCo 3's aging power supply.

The original TRIAD was designed to provide a conventional 512K memory configuration. It did not require additional memory-management hardware or modifications to the GIME's standard addressing capabilities.

A New Approach to Memory Expansion

The TRIAD's most recognizable feature was its distinctive triangular blue printed circuit board, substantially smaller than conventional CoCo 3 memory expansion cards.

Rather than employing sixteen individual DRAM chips or removable SIMM modules, the board incorporated two surface-mounted SRAM devices. Its unusual shape allowed the necessary circuitry to occupy considerably less space inside the computer.

Because SRAM retains its contents without periodic refresh cycles while power is applied, TRIAD avoided the refresh requirements associated with the original DRAM-based designs.

The board also reduced the electrical load placed on the CoCo 3's internal power supply, an increasingly attractive feature as the computers approached three decades of age.

The surviving Revision B board carries the markings CLOUD-9, TRIAD 512K SRAM MEMORY, and REV. B 03/2013, establishing a documented hardware revision from March 2013.

Cloud-9's installation manual, Revision 1.2, was dated April 5, 2013, and an archived advertisement from June 1, 2013, offered the upgrade for $50 plus shipping and handling.

Power Consumption and Heat Reduction

One of TRIAD's principal selling points was its substantially reduced power consumption compared with conventional DRAM memory expansions.

Cloud-9 published comparative measurements in the original installation manual, testing TRIAD against its earlier 512K SIMM upgrade.

Both boards were evaluated in a standard CoCo 3 equipped with a 6809 processor, running the MTEST512 memory-testing program for approximately two hours. Ambient temperature was recorded at 78°F.

The TRIAD memory devices reached 87.4°F, compared with 166.8°F for the earlier SIMM expansion. The voltage regulator heatsink measured 150.8°F with TRIAD installed, versus 171.6°F with the SIMM board.

The difference in current consumption was particularly substantial. Cloud-9 measured an average of 21.82 milliamperes at CN6 pin 2 for TRIAD, compared with 543 milliamperes for the SIMM upgrade.

According to Cloud-9's published calculations, these results represented approximately a 96% reduction in current consumption, while the new board occupied roughly half the circuit-board area of its predecessor.

Cloud-9 advertised TRIAD as producing approximately 90% less heat and using one-twentieth of the power of conventional 512K upgrades. These figures were based on the manufacturer's own testing, rather than independent laboratory measurements.

Nevertheless, the documented difference in current draw and operating temperature demonstrated the practical advantages of replacing older DRAM technology with modern SRAM.

Installation and Compatibility

Despite its substantially different memory technology, TRIAD retained the straightforward installation procedure used by conventional CoCo 3 memory expansions.

The original four DRAM chips, identified as IC16 through IC19, were removed from the motherboard. Two capacitors, C65 and C66, were also removed according to Cloud-9's instructions.

The TRIAD board then plugged directly into the existing memory expansion connectors, with J4, J5, and J6 aligned with CN4, CN5, and CN6 on the motherbo

Cloud-9 TRIAD+ 2MB SRAM Upgrade and Pro-Tector+/MMU — 2018–2019

In April 2018, Cloud-9 announced the next generation of its Color Computer 3 memory expansion hardware: the TRIAD+ SRAM Memory Upgrade and its companion Pro-Tector+/MMU. Together, the two products provided a modern, compact solution for expanding the CoCo 3 to 2MB of memory while retaining the low power consumption and reduced heat output that had distinguished Cloud-9's original TRIAD design.

The new hardware represented the culmination of more than two decades of Cloud-9 memory expansion development. The company had introduced its original 512K SIMM upgrade in 1997, followed by the Pro-Tector CPU protection interface in 1999 and the TRIAD 512K SRAM upgrade in 2013.

Unlike the original TRIAD, which provided a conventional 512K memory configuration, TRIAD+ incorporated a full 2MB of static RAM. However, the CoCo 3's original GIME memory-management hardware could access only 512K of that capacity. To utilize the remaining memory, Cloud-9 developed the Pro-Tector+/MMU, combining processor protection circuitry with expanded memory-addressing capabilities.

The resulting system offered CoCo 3 owners a substantial increase in memory without the complicated stacked expansion boards, extensive wiring, or older DRAM technology associated with some earlier 1MB and 2MB upgrades.

Development and Introduction

The TRIAD+ development history is unusually well documented through contemporary announcements by Cloud-9 developer Mark Marlette.

On April 22, 2018, Marlette announced that TRIAD+ and Pro-Tector+/MMU would replace the company's existing TRIAD and Pro-Tector products. The announcement included photographs of a TRIAD+ circuit board marked Revision A, March 2018, establishing that working hardware existed by that time.

Marlette explained that TRIAD+ could operate as a conventional 512K memory upgrade when installed alone, while the addition of Pro-Tector+/MMU would make the full 2MB of SRAM available.

The initial announcement listed target prices of $45 for TRIAD+ and $30 for Pro-Tector+/MMU. These were projected prices rather than confirmed retail prices.

Development continued through subsequent hardware revisions. A later TRIAD+ board was marked Revision C, May 2018, while a surviving Pro-Tector+/MMU board carried a Revision A, January 2019 designation.

By April 27, 2019, Cloud-9 was publicly advertising the complete combination, describing it as a new generation of memory expansion hardware for the CoCo 3.

The precise date of the first customer shipment has not been established, but the contemporary announcements document the product's development and promotion well before its appearance in later archived website captures.

TRIAD+ — 2MB of Static RAM

The TRIAD+ retained the distinctive triangular circuit-board arrangement introduced with the original 2013 TRIAD.

The new design incorporated 2MB of SRAM, replacing the older DRAM-based memory expansion technology with static memory that did not require periodic refresh cycles.

This approach reduced electrical power consumption and heat generation while eliminating the need for conventional DRAM refresh circuitry.

The compact board installed inside the CoCo 3 using the computer's existing memory expansion connections. Its relatively small footprint helped preserve internal space and reduced the amount of additional hardware required.

Unlike conventional 512K memory upgrades, TRIAD+ contained substantially more physical memory than the original GIME could address.

When installed by itself, the board operated as a standard 512K expansion, providing compatibility with the CoCo 3's existing memory-management system.

The remaining 1.5MB was physically present but could not be accessed through the original GIME addressing arrangement.

To unlock the full capacity, the system required Cloud-9's companion Pro-Tector+/MMU.

Pro-Tector+/MMU — Expanded Memory Addressing

The Pro-Tector+/MMU combined two functions in a single interface: protection of the CoCo 3's processor and additional memory-management circuitry.

Cloud-9's original Pro-Tector, introduced in 1999, was designed to buffer critical processor signals and help protect the CPU from electrical conditions associated with external hardware and expansion devices.

The newer Pro-Tector+/MMU extended that concept by incorporating the additional address-management functionality required for the TRIAD+ memory board.

The CoCo 3's GIME normally provides access to 512K of physical memory through sixteen Data Address Translation (DAT) registers. Each register selects an 8K memory block, allowing the processor's 64K address space to be mapped into different regions of the installed RAM.

Accessing 2MB requires additional physical address-selection capability beyond the GIME's original configuration.

The Pro-Tector+/MMU supplied the necessary expanded memory-management functionality, allowing software designed to support the extended configuration to access the full 2MB installed on TRIAD+.

The combination therefore provided a substantial increase in available memory while preserving the CoCo 3's original processor and GIME.

Two Operating Configurations

Cloud-9 offered TRIAD+ in two configurations, allowing owners to select the memory capacity appropriate for their systems.

TRIAD+ alone — 512K accessible

With only the TRIAD+ board installed, the CoCo 3 operated as a conventional 512K machine. Although the board contained 2MB of SRAM, the original GIME could address only the first 512K.

This configuration provided the advantages of modern SRAM technology without requiring the companion memory-management hardware.

TRIAD+ with Pro-Tector+/MMU — 2MB accessible

Adding the Pro-Tector+/MMU enabled the full 2MB of physical SRAM to be addressed.

Owners could therefore begin with the TRIAD+ memory board and later expand their systems to 2MB by adding the companion interface, rather than replacing the memory expansion board.

This modular approach distinguished TRIAD+ from earlier memory upgrades that required separate, dedicated hardware configurations for different capacities.

Power Consumption and Reliability

Like its predecessor, TRIAD+ was promoted as a cooler-running, lower-power alternative to conventional DRAM memory expansion boards.

Cloud-9's advertising described the SRAM design as operating approximately 90% cooler and consuming one-twentieth of the power of older 512K upgrades, while occupying roughly half the circuit-board area.

These claims reflected the advantages Cloud-9 had previously documented for its original TRIAD design. They should be understood as manufacturer-reported comparisons rather than independently verified measurements specific to every TRIAD+ configuration.

The reduced electrical load was particularly significant for aging CoCo 3 systems, whose original power supplies and internal components had already accumulated decades of service.

The Pro-Tector+/MMU added another element of hardware protection by buffering critical processor signals, extending the protective concept introduced with Cloud-9's earlier Pro-Tector interface.

Software Compatibility and Applications

Expanding the CoCo 3 beyond 512K provided additional opportunities for operating systems and applications capable of using the larger physical memory configuration.

NitrOS-9 was particularly well suited to systems with expanded memory, allowing additional RAM to support multitasking, larger applications, and memory-intensive operations.

Cloud-9 also promoted the TRIAD+ and Pro-Tector+/MMU combination as providing improved compatibility with certain software titles that had previously required special patches or workarounds.

In its April 2019 advertisement, the company specifically mentioned Donkey Kong Remix and Sierra adventure games as examples of software that could benefit from the new hardware configuration.

These compatibility improvements were presented as features of the complete TRIAD+ and Pro-Tector+/MMU combination, rather than the standalone 512K memory board.

Pricing and Availability

Cloud-9's April 2018 development announcement proposed target prices of $45 for TRIAD+ and $30 for Pro-Tector+/MMU.

A later Cloud-9 product listing advertised two configurations:

• TRIAD+ 512K: $55 plus shipping and handling, including a Tandy 512K case badge.

• TRIAD+ 2048K: $115 plus shipping and handling, including the Pro-Tector+/MMU and a Tandy 2048K case badge.

The product listing also advertised an installation manual and an RS-DOS memory-testing program supplied or available with the upgrade.

The exact date of this later pricing has not been established. However, the April 2018 development announcement and April 2019 advertisement confirm that the product was being publicly promoted several years before the surviving mid-2024 website capture.

Surviving Hardware and Documentation

Several documented hardware revisions help establish the development history of the TRIAD+ system.

The earliest identified TRIAD+ board is Revision A, dated March 2018, photographed in Mark Marlette's April 22, 2018 development announcement.

A subsequent TRIAD+ Revision C board is dated May 2018 and appears in Cloud-9's April 2019 advertising.

The companion Pro-Tector+/MMU board pictured in that advertisement carries a Revision A date of January 2019.

These photographs establish a progression from the original 2018 TRIAD+ development hardware to the complete two-board combination advertised in 2019.

They also provide useful identifying details for collectors attempting to distinguish the later TRIAD+ from Cloud-9's original 2013 TRIAD 512K SRAM upgrade.

Historical Significance

The TRIAD+ and Pro-Tector+/MMU combination represented a significant refinement of the large-memory upgrades developed for the Color Computer 3.

Earlier designs, including DISTO's 1MB and 2MB expansions, had demonstrated that the CoCo 3 could operate with substantially more memory than Radio Shack originally intended. However, these systems often required complicated additional circuitry, multiple interconnected boards, or extensive installation modifications.

Cloud-9 approached the same challenge using modern SRAM technology and a compact, modular hardware arrangement.

The TRIAD+ board provided the complete 2MB of physical memory, while the Pro-Tector+/MMU supplied the additional addressing capability needed to utilize it. This separation allowed the memory board to function independently as a conventional 512K upgrade or as part of a fully expanded 2MB system.

The design also combined increased memory capacity with lower power consumption, reduced heat generation, and processor signal protection.

Introduced more than thirty years after the CoCo 3 first appeared in 1986, the TRIAD+ demonstrated the continued technical development of the Color Computer platform by independent hardware designers.

Together with the original TRIAD, it stands as an important example of Cloud-9's efforts to modernize, preserve, and extend the capabilities of Tandy's final Color Computer.

Sources and references

• Mark Marlette, Facebook announcement of TRIAD+ and Pro-Tector+/MMU development, April 22, 2018.

• Cloud-9, We Know Memory, TRIAD+ and Pro-Tector+/MMU advertisement, Facebook publication dated April 27, 2019.

• Cloud-9, TRIAD+ 512K–2048K SRAM Upgrade, archived product webpage and pricing.

• Cloud-9 TRIAD+ Revision A circuit board, March 2018.

• Cloud-9 TRIAD+ Revision C circuit board, May 2018.

• Cloud-9 Pro-Tector+/MMU Revision A circuit board, January 2019.

• Cloud-9, TRIAD 512K SRAM Upgrade User's Manual, Revision 1.2, April 5, 2013, for background on the preceding TRIAD design.