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Tandy! Pocket! Mania! @ Floodgap Retrobits

[The Pocket Computer family. Click for an enlarged view.]

Welcome to Tandy! Pocket! Mania! @ Retrobits, my section devoted to the diminutive yet popular 1980s Tandy Pocket Computer line. Yes, there are quite a few Pocket Computer sites out there, but most of them cover the Casio and Sharp models that Tandy cloned and merely add the Tandy variants as a footnote or label variation. That's a shame, because in their Tandy and Radio Shack forms these models enjoyed far wider exposure and apparent commercial success based on their easy availability in the used and collector markets, and as a result took on a life of their own independent of the machines they were descended from. In TPM!, we'll look specifically at their ancestry, their options and their history, and even up the information gap for these 20th century ancestors of the PDA.

To help us on our story, we'll use the boy mascot from the PC-4 Programming Manual. He's getting caffeinated up and should be raring to go any minute, and yes, his quips and quotes are all directly scanned from the manual. Before we begin, click the picture on the far left for a 117K sampler of all that as available in the Pocket Computer line from my collection. All of the units you will see pictured are in the author's possession.

This site was last modified on 10 February 2024.

I appreciate receiving your comments, corrections, fan mail and offers of cash. Send it all to ckaiser@floodgap.com. I would also gratefully ask you to obtain my permission before posting or redisplaying photographs from this site on yours. Thank you! -- Cameron Kaiser

Are you getting rid of Pocket Computer equipment? Please don't throw it away! I am always interested in your extra or unwanted Pocket Computer systems, peripherals, paraphernalia and manuals. Please send me E-mail at ckaiser@floodgap.com with your desired arrangements and let's see if we can't work something out!

What Is A Pocket Computer?

The Pocket Computer line was any of a series of specific Sharp and Casio handheld computers (and other brands, but in particular these), all programmable in BASIC, designed to be calculator-sized and extremely portable but capable of more complex calculations and programs than a regular pocket calculator. Most had expansion options, most commonly cassette and printer interfaces, and many accepted RAM expansion as well. In our use here, we're specifically talking about the Tandy Radio Shack Pocket Computers, which are rebadged versions of specific members of the line. The Pocket Computers extended long after Tandy Radio Shack had exited the business -- some were produced as late as 1998 -- but their heyday was the mid 1980s and that's where the history of the line gets most interesting.

The Rise of the Pocket Computers

Naturally during the late 1970s with the rise of the microcomputers, there was no small amount of interest in a miniaturized version that could act as a microchipped companion. (Such things had lapsed into wild flights of fancy at the hands of futurists; Alan Kay's Dynabook still doesn't exist even with today's technology, despite being conceived of in the 1960s.) The state of computers and computerized applications being what it was at the time, the desire was to have something calculator-sized that could be flexibly programmed like the desktop computers of the day.

The first of the "true" Pocket Computers, excluding higher-end calculators and the like, was the Sharp PC-1210 (1980). (I don't count the 1977 Sharp PC-1201 as the first, despite the PC-1201 being labeled as a Pocket Computer, as it doesn't have a full character set.) Based on the form factor of the Sharp EL-5100 calculator series, the PC-1210 offered 896 bytes of memory and the BASIC programming language (in a simplified variant called S'-BASIC "S Prime BASIC," S being short for Sharp), using a 4-bit dual CPU system, for an MSRP of US$229. ['BASIC is flying around the world.'] The unusual RAM total came from a combination of its 1024-nybble RAM (1024 * 4 bits = 512 8-bit bytes), and an additional 128 bytes in each of the three display chips. Because of this odd memory layout, only an effective 400 bytes were available for user programs although the parsimonious nature of S'-BASIC did mitigate the limitation somewhat; even considering its size, however, the memory constraint of the PC-1210 was fairly dire for the price point and Sharp followed with the PC-1211 shortly after. The PC-1211 used the same architecture but had 1536 bytes of main RAM (3072 nybbles) along with the 384 bytes of display memory for 1920 bytes total RAM and 1424 bytes for user programs.

Choosing BASIC as the programming language for the new line was an extremely perspicacious decision. It transcended the sometimes opaque programming methods and "languages" used by other programmable calculators, and gave the impression of using a full desktop machine as virtually all desktop microcomputers of the day (such as the Apple II, Commodore PET and the Tandy Radio Shack TRS-80) used it as their primary programming language too. Sharp's BASIC also established the two-mode paradigm that virtually all Pocket Computers since used where the computer lives in a calculator-like RUN mode on start up, allowing "instant" arithmetic like a standard calculator as well as program execution, while a switch or key sequence will switch it to PROgramming (or WRiTe) mode where program lines can be entered or edited. This elegant division of modalities made it possible to have a Pocket Computer replace a calculator for quick one-offs, yet not have BASIC clashing with immediate expression evaluation.

To keep data sets small, the Sharp units also introduced the concept of "fixed memories" -- every unit had 26 variables available, either string or float, accessed as A-Z. A letter could only be one type or the other (no separate A and A$), and array indexing operated on the 26 "memories" directly (so that A$(3) was actually an alias to C$). For programs needing greater dataspace, "flexible memories" allowed allocating free memory as additional variable space accessed also by array indexing, and some later units could even do this dynamically under program control. These variable conventions and the "fixed" versus "flexible" memory allocation were another feature set also maintained in all of the succeeding units. (String support was limited to 8 character variables in the PC-1210/1 and thus would be generously described as deficient, something not addressed even partially until later models.)

Now that the memory capacity was no longer as crippling a limitation, the PC-1211 variant was considerably more popular and attracted Tandy's attention, who was looking for a small portable computer to complement their newly popular Color Computer and TRS-80 computer lines. Typically, Tandy's main interest was almost always to resell rather than develop internally if it could possibly avoid it. For this reason, the PC-1211 was simply rebadged as part of the TRS-80 line and was introduced as the Pocket Computer PC-1 with an MSRP of $249.95 in 1980. Dubbing S'-BASIC as "Pocket BASIC," Tandy heavily hyped its desktop-like qualities and expansion options throughout their entire sales network and their Radio Shack retail store chain. With this massive international exposure, the PC-1 was extremely popular and Tandy simultaneously imported most of the Sharp peripherals, in particular the printer and tape interfaces, to rebadge and sell as well as software custom for the unit. The PC-1 was obviously produced in some numbers as it is one of the easiest units to come by; Tandy followed it with heavy cassette software support and a collection of books, guides and manuals for the hobbyist. It was later reduced to $149.95.

The Triumvirate Golden Age

[The 'Pocket Computer Triumvirate' from an October 1983 ad. Click for a larger view.]

Encouraged by the positive response to the PC-1, Tandy raided the Sharp line for more systems at more pricepoints. For the "power user" slot, Tandy selected the 1981 Sharp PC-1500 and released it as the Pocket Computer PC-2 in 1982. A dramatically different architecture than the PC-1, the PC-1500/PC-2 was powered by the 8-bit LH-5801 CPU at 1.3MHz, on par with many desktop systems; had a "gapless" LCD with 156x7 pixel resolution, making bitmap graphics possible even on the small LCD; a greatly enhanced Sharp BASIC Tandy dubbed "Extended Pocket BASIC"; a real-time clock and a small bump in memory (3072 bytes of system RAM and 512 bytes of display RAM, with 1850 bytes free for user programs) with an expansion slot allowing up to an additional 16K (!). In fact, alone amongst all the Pocket Computers, the PC-2's hardware could be accessed directly, even through machine language! All this power came at a cost, however -- while still highly portable the PC-2 was definitely no longer pocket sized, except possibly by Andre the Giant's standards. Nevertheless, it became similarly very popular and Tandy shored it up by also offering the tape, printer, serial port and memory options of the PC-1500. (The later PC-1500A was not rebadged by Tandy.)

[The Ghostbusters, Egon's PC-4 in tow.] However, what Sharp lacked and what Tandy wanted was a ultra-value-priced unit. For their low-cost model, Tandy made the fateful decision to split the Pocket Computers into separate architectures and recruit instead from Casio's competing line in 1983. The first of the Casio derivatives was the ultra-low-end 1983 Pocket Computer PC-4, based on the Casio PB-100. Although hobbled by a 4-bit CPU, only 544 bytes of RAM (of a total of 1K [2048 nybbles]) and a 12-character LCD, it had a very attractive small form factor, low power requirements, and most important to Tandy, an enticingly low price tag. It is probably for this reason that the PC-4 sold in large numbers and became nearly iconic of the line, even making it to the movies -- Egon Spengler (Harold Ramis)'s computing device of choice in Ghostbusters was a PC-4 with a cassette attachment. The leads of the cassette attachment were wired in a most grotesque fashion into his coat so that the device could just dangle. (Unfortunately for enthusiasts of the paranormal, the PKE meter attachment was not sold in the United States.) In 1985, the PC-4 was re-released in an upgraded version with new ROMs, but alas no additional memory, in a chimaeric form partially based on the Casio PB-100F. Unique for the line, the PC-4 introduced the concept of independent segmented program spaces to the Pocket Computer family (its ancestors were all one-program units) and for the first time what could be considered to be a rudimentary internal filesystem. Naturally, its own selection of external peripherals was readily available, including a practically essential 1K RAM pack.

Despite its impressive specifications, the PC-2 was not very approachable to the casual enthusiast due to its size and cost, and furthermore neither the PC-2 nor the PC-4 were backwards-compatible with the PC-1 because of their dissimilar architectures. Fortunately, Sharp had already issued a faster and smaller follow-on to the PC-1211 in the form of the 1982 PC-1250, using a 8-bit CPU that was otherwise fully upwards compatible with the S'-BASIC of the PC-1211. This version became the first of the Pocket Computer PC-3 line released later in 1983 after the PC-4, placed in the midrange market slot, but the RAM capacity was not much better than the PC-1 it was intended to replace (despite having 2K of RAM, only 1438 bytes were free for user programs). Fortuitously, Sharp quickly followed the PC-1250 with the 4K PC-1251; Tandy followed suit and released the PC-1251 as a redesigned Pocket Computer PC-3 (the PC-3A, "now with 4K RAM") in 1984.

Together, the PC-2, PC-3 and PC-4 represented the "triumvirate" of the Tandy Pocket Computer lines, with a unit positioned in each of the three key markets. They enjoyed wide support from the Radio Shack retail stores and were easily the three most popular units by far; in fact, they are the three units I recommend in three different targets -- see the individual pages for why:

For the power-user who wants ultimate programmability, get a PC-2.
For the casual enthusiast who wants high portability and high usability with little additional hardware, get a PC-4.
For a good balance of size, expandability and performance, get a 4K PC-3.

It is noteworthy that Tandy stopped badging the Pocket Computers with the Radio Shack and TRS-80 brands in 1984 and used just plain Tandy thereafter, first with the 1984 refreshed PC-3 and 1985 PC-4 and then subsequently on all of the Pocket Computers that succeeded them. ['Bummer.']

After the Golden Age

Unfortunately, the "triumvirate" was clearly the peak of the Tandy Pocket Computers -- a fact thrown into sharp relief by their successors.

For the Casio users, Tandy chose three units from the Casio stable, calling them the Pocket Scientific Computers and emphasizing their additional specialized mathematic functions. In the flagship slot, Tandy chose the FX-780P and its expanded sibling FX-790P and released them as the Pocket Scientific Computer PC-5 and Pocket Scientific Computer PC-6, respectively, in 1985 and 1986. Sleek and impressive units on the outside with a generous 24-character LCD inside, they were nevertheless plagued by poor build quality, an impractical split keyboard design, dubious internal features and kludgy expansion options (using the PC-4 peripherals, but requiring an inelegant link cable to handle the physical case incompatibilities). The 4K PC-5 lasted less than a year before it was rapidly eclipsed by the 8K PC-6, which was expandable to 16K to boot, and thus the PC-5 is correspondingly much harder to find by collectors. (Nevertheless, despite their multiple iniquities, the beautiful exteriors of both units make them very popular items on the used market today and NOS PC-6s often command prices nearly as high as when they were sold new!)

In the value slot, Tandy selected the horrific Casio FX-5200P and released a slightly upgraded version of it as the Pocket Scientific Computer PC-7 simultaneously with the PC-6. Intended to replace the PC-4, the PC-7 was actually a gigantic step backwards, taking the worst elements of the PC-5/6 design and combining them with the worst elements of the PC-4 (especially the cramped RAM and screen). Certainly what was already considered a liability in 1983 would be considered even worse in 1986, but what was most damning of all was that that it had no expansion options of any kind.

However, Tandy wasn't finished insulting its loyal customer base and for an encore finished the line in 1987 with the disappointing Pocket Computer PC-8, based on the Sharp PC-1246 (to distinguish it from the Casio models, the Scientific moniker was dropped and the old designation restored). Compared with the PC-7, the PC-8 was a welcome improvement, but compared with the PC-3 it was designed to replace, it was an utter travesty. Retreating to a four-year-old design (the PC-1245 and the succeeding PC-1246 were originally released in 1983 as low-cost versions of the PC-1250!), the PC-8 had a smaller screen and even less memory than even the original 2K PC-3 (a pathetic 1278 bytes available for BASIC). Its only saving graces were that at least it could use the PC-3's peripherals directly, and its rugged hard case.

Although the PC-6 was a reasonably bright profit spot despite its compromises, the otherwise generally lackluster showing of the later members of the line had a predictable effect on sales, and the choice of models demonstrated a clear preference towards quick and cheap rather than powerful and useful which unfortunately matched Tandy's growing ambivalence towards its non-PC computer lines in general. With the success of the Tandy 1000 showing the way towards today's Wintel hegemony, even the venerable Color Computers' days were clearly numbered and the (intentionally?) ailing Pocket Computers thus had no executive chance for survival. The last model to be sold was actually the long-lived PC-6, which outlasted all the other members of the line until around 1991, when it too was laid to rest. ['Can that be done?']

The Modern Pocket Computer

For their part, Sharp and Casio continued to produce and develop their Pocket Computer lines into the 1990s. As BASIC programmability became less important, cross-pollination occurred with their respective classroom and scientific calculator designs and ironically spawned models closer to being "pocket scientific computers" than what Tandy foisted on the public in 1986. These true descendants are of course easily available today, and at mass-market pricepoints, putting them into the hands of millions of unsuspecting schoolchildren.

['Let's perform schedule management using a machine. It's kind of like science fiction, isn't it?'] However, the spiritual descendants of the Pocket Computers are obviously PDAs, and today, to a lesser extent, smartphones. While Windows Mobile may inspire fits of nausea in the susceptible user, it and other PDA operating systems such as Palm OS and Symbian were the operational evolution of the concept of the "peripheral brain." For years I couldn't live without my Palm Zire 72 in my pocket to hold various technical texts and act as my pocket organizer (a humourous thought about this is in the clip from the PC-4 Programming Manual at right), my address book and play a few games here and there. Self-hosted PDA programming languages like Plua give back the programmability of the Pocket Computer, something missing from many modern smartphones and tablets, but their expanded host connectivity nimbly supersedes most peripheral needs. The Pocket Computers offered a lot of computing power in a small space for the day; while no niche today best represents them, for years PDAs delivered on a similar promise.

Perhaps the Dynabook will one day be in reach. When it is, we will remember the Pocket Computers as part of the ancestry that brought it to us.

Getting One Today

[The PC-7 has a strong opinion about online auctions.]

Other than their collectors' value, Pocket Computers still retain a lot of use in specialized fields. In 1997, almost a decade and a half after its market introduction, I was still using a PC-4 to do biochemistry research simply because it was easy to program it for the particular concentration gradients I had to generate, and its low power requirement meant I had long battery life for doing lots of computation. Compared to the programming languages on some modern calculators like the Texas Instruments series, some mathematical operations are frankly more easily expressed in BASIC. Plus, a combination of a Pocket Computer and a printer can make a simple little terminal for hard copy that won't take up much room on the corner of a desk or lab. And isn't it fun to hack on one just to say you can?

For all these reasons, plus conversations at cocktail parties and maybe picking up a geek gadget girl/guy/etc., a Pocket Computer is still a fun addition to one's collection. Here are a few general tips to acquiring and maintaining them, with more specific notes on the specific model pages.

If you're looking for a computer or particular peripheral to buy, Tandy Pocket Computers and their accessories are easily found on sites such as eBay with a little bit of patience; they also turn up at computer fairs, swap meets/hamfests and the like for usually more favourable prices, although those units tend to be knocked around a little more (consider them well-loved). Pretty much any country that has Radio Shack stores will have a user base of some size, and some TRS-80 specialty stores and mail-order enterprises will still stock NOS or lightly used units for a bit more green. It is my policy not to post suggested prices, lest I be accused of manipulation, but in the numbers that are presently available it won't cost a great deal of money for most of the more common members of the series.
One of the "seemed like a good idea at the time" things about the line is the rechargeable battery packs used in most of the printer interfaces. Intended so that you could have your printer on the go, the NiCad batteries had a tendency to do what all NiCad batteries have a tendency to do, viz., go flat and eventually fail to hold a charge. Because the printer is typically powered by the batteries, not by the charging circuit, connecting an external power supply generally won't fix the problem and so many of the used printers you'll find will pretty much be doorstops. The only sure fix is to only buy NOS so you can ruin the battery yourself, or rewire it internally, or try to replace the NiCads if you can find equivalents (NiMH won't work without conversion) and have skillz with a soldering iron. You may also want to try any or all of the NiCad "voodoo" tricks out there too to see if you can coerce the batteries back into some sort of operation.
Fortunately, Sharp and Casio did release AA battery-powered printers which thus completely avoid this problem -- but unfortunately Tandy never imported them. Nevertheless, at least one of them can be found fairly easily on the used market; see the PC-1/3/8 page for more.
Speaking of printers, be sure to spec paper for your unit correctly. Many of the models are thermal, but not all, and some use slightly smaller paper sizes. An office supply store may be able to help you if you bring them the spent spool for comparison, or you might be able to fashion your own by unwinding a larger reel down to the printer's capacity and lopping off an end to fit.
Don't turn your nose up at non-Tandy equipment -- in fact, some of the best peripherals like the AA-battery-powered printers mentioned above were never imported by Tandy. Particularly for more obscure models, it may even be cheaper to go for the OEM part rather than the Radio Shack part unless you are an especially obsessive collector. For your reference, I have tried to collect the equivalent part numbers for imported Tandy parts, but the lists should not be considered exhaustive for all the other parts that are available.

"Where to, buddy?"

Now that you've had an introduction to the line and a "brief" discussion of their history, let's get down to the individual models. Each model page contains some photography; a discussion of the unit's merits, failings and special features; a brief collector's reference list; and links to additional resources.

Start with the PC-1, PC-3 and PC-8 Sharp models. These models are grouped due to their compatibility and strong evolutionary relationship.
Continue with the PC-2, placed on its own page due to its unique and powerful design.
Finish up with the PC-4, PC-5, PC-6 and PC-7 Casio models, again grouped together because of their close relationship.
Finally, see what else there is on Floodgap Retrobits.

I would love to hear your reminiscences and comments -- please send them to ckaiser@floodgap.com.