Palmtop Computer Design Problems

Design points and problems in palmtops.

Given there is so much experience out there on designing decent palmtop computers, I can only ascribe most of the multiple design problems I seem to encounter to the grasping hand of cost accountants. My suggestion is to offer better as optional extras, where possible, or make it easier for third party vendors to provide upmarket additions. I would hope this would move more people from if only it had an X to if I add Y this will do what I need.

AC Adaptors

Summary - must be universal.

The AC adaptor for a pocket computer should be able to accept any common input voltage. Most use plugpacks that only work in a single country. Considering pocket computers are aimed at executive types who travel overseas, this is really idiotic. If there is too much of a cost barrier, at least have an optional universal voltage adaptor available.

Notebook computers got this right ages ago. So did cellular phones. If it is too sensitive a cost issue (and I accept it may be), then as an optional extra.

While on that point, why isn't a full bridge rectifier standard on pocket computer power input sockets? You could then use any AC or DC plugpack that provided the correct voltage, without having to worry about the polarity of the plug. I've even heard of pocket computers that are damaged by incorrect polarity or voltages. Texas Instruments had this one solved in their TI58 calculators back in 1976.

The DC power plugs in pocket computers are another pain. Everyone has their own idea of what plug to use. They all seem to be different. There are now at least 10 different type of DC plugs seen in pocket computers, and this is no help to the buyer.

Some of the power bricks supplied with PDAs are larger than the computer. The phone companies seem to be able to make very lightweight switch mode power supplies, so why not use the same sorts?

However the real solution is not to carry yet another brick with you. The computer should last long enough on batteries that you don't need to bother with a power pack, except maybe at home.

If there isn't an automatic suspend-resume option on a computer, don't buy it. However then you should be able to set the period before the suspend actuates to be different (longer) when you are running from an external power supply. Most do this, but some missed it.


Whatever you buy had better have applications that suit how you need to work. Otherwise, why carry it? Here is what I need.

Able to accept all of my working data files. This includes a couple of 200 to 500 person mailing and phone lists, some catalogs with a few thousand items in them, and a whole bunch of shorter lists. A flat file database will suffice. Should be able to turn out mailing labels, or make files suited to form letter generation. Leave a RDBS to the aftermarket. The Sharp PC3100 sucked big time due to running slow if it had any reasonable quantity of data.
A flexible PIM
In my case the Psion Agenda application. Most contain something, but you need to check how much it can handle before falling over. Your PIM should be reasonably competitive with a full scale PIM for a desktop machine. Either the PIM or the alarm should be able to handle stuff like alarms at 10 a.m. on the fourth Wednesday of each month, irregular working periods (45 minute appointments for example) etc.
Word Processor
Capable of handling letters, form letters, posters, rough layout for a magazine, plus web pages. Must have a spelling checker, thesaurus and the major parts of a modern word processor. You will probably have to do without equation editing, and similar esoteric functions. Most of the pen operated handheld systems (Newton, Palm Pilot, Windows CE) either totally lack a word processor, or can only handle a few thousand characters.
Scientific calculator
Plus a simple calculator. Simple one, so you can easily and quickly work the buttons. Scientific one, because sometimes you absolutely require fancy trigonometric or statistical functions.
I don't use it extensively, but often find a spreadsheet the easiest application for solving "what if" problems. Should at least be able to handle simple business needs, including simple graphs. Many of the handheld pen systems lack a spreadsheet. I don't understand why.
Clock with multiple alarms.
Everyone should have these, but not the Sharp PC3100, Lexicomp LC8620, etc., so check it. The alarm should be loud enough to hear. The alarm sound should be able to be switched on, or off, or suspended for a period (to avoid interrupting a meeting say). The period for which the alarm will sound should be variable. If the alarm is not responded to, it should repeat less frequently, and not drain the battery.
Programming language.
Not so much for you to write a program, but so someone out there is happily writing programs you can use. Virtually no Japanese organiser includes a programming language, and you don't seem able to get one. Neither do Windows CE or Palm Pilot systems (but at least you can buy languages for them).

Many very popular palmtops don't include even this minimal subset of functions.


Summary - AA or forget it.

If the battery is not standard, forget it. Every portable computer I've ever seen has eventually had battery problems. At which point you have to buy new batteries. If they are non-standard, you will find they are expensive. Worse, you may find they are no longer popular, and can no longer be obtained. In any case, laptop computers don't run on batteries, they just hold their breath for a few hours between power points and recharges.

Standard batteries for a pocket computer would typically be AA cylindrical. I'm not very keen on the smaller AAA size, or N size, as these have far less capacity, and I doubt they will keep a pocket computer working for long periods. But even smaller standard cells are better than non-standard. In this context, "standard" means you can buy them at a local newsagent, not a specialist shop.

Designers don't really like the cylindrical batteries, as it is hard to package them efficiently into small spaces. This is one reason so many portable computer makers go to a custom battery package, usually rectangular. My advice is to reject such custom solutions - force the makers to move to standard batteries. They could always use the wonderful Psion and Hewlett Packard OmniGo idea of putting the batteries in the hinge.

One hopeful sign is that battery maker Duracell is trying to sell a "new standard" set of rectangular batteries to computer makers. If this does become popular, that would be a nice resolution to the problem of packing efficiency. But for the moment, my advice is, if it doesn't run on AA cells, refuse to buy, and tell the retailer and manufacturer why.

Battery Life

Summary - you can't have everything.

Some pocket organisers can get a year out of a set of batteries. Most do this by using a very slow processor clock. In a Casio Boss, for example, you can type too fast for it to respond. I'd rather change the batteries more frequently, in exchange for better speed. On the other hand, running Windows isn't on the cards soon. If a pocket computer doesn't last at least a day, it isn't worth considering, and a couple of weeks isn't an unrealistic expectation.

Be warned that genuine Windows 95 pocket computers, like the IBM PC110 and the Toshiba Libretto, get only a few hours life from their batteries.

Add-on modems that lack their own batteries can often have a really severe effect on battery life. This appears a particular problem with fast PCMCIA modems in Windows CE pocket computers, with reports of battery life reduced to minutes.

Batteries, Rechargeable

Summary - both rechargeable and throw away.

The Hewlett Packard LX100 and LX200 series got this absolutely right. You can use either rechargeable AA batteries, or you can use regular AA alkaline batteries. Regular batteries have greater capacity, a much longer shelf life, and you can buy replacements almost anywhere. Rechargeables have a much lower lifetime cost. Being able to use either is the best of all worlds.

My Sharp PC3100 can not use rechargeables, and so after the first few sets of batteries you start looking for battery life saving strategies. My Lexicomp LC-8620 uses only rechargeables. So far that has not been a problem, but one could imagine being caught without a spare recharged set. If you can't get a pocket computer that can use either, go for the rechargeables if you are a heavy user, or the standard alkaline batteries if you rarely use the pocket computer.

Rechargeable alkalines are not really a solution to this situation. I hope to add details of a trial soon.


Summary - 9 pin male D RS232, 25 pin female D printer.

Sometimes it seems every maker of small computers comes up with their own variety of I/O connector. If you buy such a computer, you will find you need to buy an (expensive optional) cable or converter, before you can connect to standard peripherals.

Like it or not, the standard connector pattern these days is that provided on clones of IBM computers. Serial ports are 9 pin male D connectors, printer ports are 25 pin female D connectors. I grant that some computers are too small to permit these connectors, however a remarkable number of pocket computers use custom connectors despite having room for standard ones (Olivetti Quaderno, Sharp PC3100, Zeos Pocket PC are obvious offenders).

If you accept non-standard connectors, and want to use the peripheral ports, you end up carrying round a great lump of conversion cables to go with your pocket PC. This stunt just externalises the problems of making a small computer. Some pocket computers are really blatant about this. Take a look at the Psion 3a external cables, where conversion electronics are packed into a large lump in the cable.

I thought the Lexicomp LC8620 got this exactly right, with dead standard connectors for RS232 and parallel printer. Really handy.

If connectors are really that much of a problem for designers, then a totally standard IrDA port would be a help (the Apple Newton had infra red, but it wasn't IrDA). I've been using the Psion 5 infra red port with the Hewlett Packard 5MP laser printer, with the Canon BJC80 colour bubble jet printer, with the Ericsson SH888 modem equipped GSM mobile phone, and even with my notebook computer. It is a handy gadget. Perhaps the Bluetooth radio link will eventually be a very good supplement.

Connector Covers

Summary - I don't see a winner.

Covers for connectors are another problem. Some makers provide clip on plastic or metal covers, like the Sharp PC3100. This almost guarantees that the cover gets lost in some hotel room, and is never seen again.

I prefer covers that remain attached to the PC, and don't get lost. The Psion 5 covers remain attached. Lots of laptops got that right, so just what is the problem?

Having said that, one big complaint is that such covers are frequently so fragile that they break off. The flexible covers on the Apple Newton never last the life of the system. The plastic doors on many notebooks tend to break off.

An additional problem with attached covers is that some designs get in the way of cables and plugs when opened. I don't know if sliding covers would be a solution, although the Micron notebooks had a real nice solution along these lines. Probably not on pocket machines, given the restricted space available.

The HP range use a recessed male connector. The Psion 3a goes one better and has a shroud that retracts into the body of the system (but sometimes jams there).

Informative labels moulded into the covers or nearby on the body wouldn't be a bad move also, although experienced users probably don't care. Many makers do include such labels.


If a machine has a cradle, you still need a small cable connection. Cradles are large and awkward to carry with a portable machine. A cable is lots smaller. Cradles are for sitting on a desk, not for travel.

Data Compatibility

Summary - essential.

Unless you can manage without any desktop computer, your pocket computer data needs to be compatible with what is running on your desktop system. Some makers provide conversion utilities. Mostly you have problems. Even when a conversion method is available, it is sometimes excessively costly, or often only suits some programs. Typically it will only handle an MS Windows system, which isn't much use if you use a Mac or Unix.

There are efforts by hundreds of manufacturers to create a data interchange standard based on XML. This initiative is called SyncML. I certainly hope that it manages to take the market, but I suspect that Microsoft will decline to join.

Given this isn't available yet, you have to do it yourself. These days I look for ASCII, or DCA and RTF for text, WK1 or similar for spreadsheets, and CSV for database, with GIF and/or JPG for graphics, and Postscript for print ready material. Simple HTML can be very useful also. Damn few pocket computers supply even that range.

Be warned the Windows CE systems synchronise only with Microsoft Office products, not even with other Microsoft products. Many other palmtop systems handle a far wider range of products, but often have problems with new versions of Microsoft products, especially Outlook and Outlook Express.

Desktop Needed

Summary - do you need a desktop computer as well?

A lot of us don't really need a desktop computer, so finding that one is absolutely required before our pocket computer can be used can come as a nasty shock. Typical "two part" computers include all the Windows CE models (which require that you have a Windows computer as well), the Palm Pilot pen computer, and the Franklin Rex organiser.

Items to check include whether you can print direct from your pocket computer, whether you can make a back up copy of its contents without another computer, whether it includes a full enough range of software or only a small subset of what you might need, whether you can install additional programs without another computer.

I was staggered to discover that Window CE 1.0 computers had no way to print direct from the computer (except for the HP varieties, as HP added this function). Luckily this seems to be fixed on later models.

Desktop Integration

Summary - does it integrate with your desktop computer?

Can you easily transfer files to and from your desktop? Is conversion needed (it almost always is)? Is the conversion easy or hard (the best ones are so transparent many people don't realise it is being done)? Are formatted documents transferred correctly with all formatting retained? Can you transfer more than one pocket computer to a single desktop or vice versa? Can you use only one style of desktop computer (Windows compatibility is little use to a Macintosh user)?

Many conversion routines do a far better job from the pocket computer to a desktop than the other way. Don't believe me? Try moving a word processed file containing tables, drawings and equations to a pocket computer. I don't believe there is anything on the market that can handle this.


Summary - few choices.

There are few choices in a pocket computer. Battery life is a real problem, and only passive LCDs without a backlight last any decent time. You often can't even go for an optional backlight, as that reduces the visibility of the display when it isn't backlit.

Unless someone comes up with a new technology, I can't see these tradeoffs changing soon. Despite this, Apple and all post 1996 makers have provided optional backlights. My own experience is that adding a backlight (Psion 5 and 3c vs 3a) markedly reduces display quality in mid level light conditions. Using the backlight takes more power than the rest of the computer functions combined, so battery life is significantly reduced.

Touch sensitive displays are often markedly less viewable, and more likely to need a backlight. The original Casio Cassiopea and Compaq Windows CE machines had an absolutely terrible unreadable display, probably as a result of that combination of touch sensitive and backlight. I have a Psion 5 with a touchscreen, and the display is markedly inferior to the much older Psion 3a. The GeoFox 1, similar to the Psion 5 but without a touch screen, has a wonderful display by comparison.

Reflective displays are typically very hard to read in dim light, but have the advantage of eliminating the power consuming backlight. They can have good contrast in bright conditions. Transflective displays can optionally use a backlight, but are generally not otherwise inspiring, even in good light. Colour reflective displays are becoming more common, thanks to digital cameras and Windows CE systems, with Sharp, Sony, Philips, Kyocera and Matsushita all planning up to 8 inch models for 1999. Hitachi and Epson are looking at quarter and half VGA models at the same time. Different approaches are used. Sharp, Toshiba, Sony and Phiilips are using TFT, while Hitachi and Kyocera are using STN. Epson is using thin film diodes, and Matsushita seem undecided. Expect back electrode reflectance up to 30% from the current 10%, with thickness a third less, and power consumption around 15% of current models. We can hope for good news on the display scene around 2001, albeit at a high price both in dollars and in power consumption.

In 2001, we find the ubiquitous SuperTwist Nematic (STN) in miniature computers hasn't gone away. The backlight still eats power, and means you can't see backlit displays in sunlight. The whole thing is glass sealed, and far too fragile.

Organic light emitting diodes (OLED) and cholesteric LCD (CLCD) are promising. Lower power consumption (75% less), visible in bright sunlight, wide viewing angle, and can use flexible plastic materials. OLEDs are faster at their refresh (needed for video) and more advanced than CLCD. OLEDs are passive matrix and likely to be more cost effective. Being an LED, the brightness is current sensitive. In a multiplexed device, this means controlling the current magnitude in the columns to within 3% (the rows are just current sinks), so although a digital device, there are analog problems in the specialist drivers. Failure to do so will not provide uniform light intensities when different images are generated. (Check eMagin Corp for example).

CLCDs are multistable, and so you have a reflective, full colour, non-volatile display, with a reflectivity approaching that of newspaper. Should be a prime candidate for electronic paper when developed more, as it retains an image with no power use. (Check Kent Displays for example).

Entirely independent of the type of display is whether the type size controllable, so you can zoom in on things you can't quite read? Is the display a decent size (640x240 or better is good, provided speed isn't compromised)?

Display Clutter

Summary - optionally remove screen clutter.

Some makers fill the display with information. This is often very distracting to users. Give users the option of how much clutter they are willing to have on the display.


Summary - nothing (yet) beats a good keyboard for long notes.

If you are looking through existing data, or just taking short notes, then handwriting recognition or pen entry can be fine. Lots of people find this is all they need. If you are writing serious amounts of new material each day, a keyboard is still essential. To be blunt, for long entries a keyboard is about two to four times quicker than handwriting systems.

The best (fastest) pen entry system I've heard about is Fitaly Stamp. In the Dom Perignon II Speed contest in July 2000, a two year record of 65 wpm was beaten, with the winning speeds being 81.74 wpm. Best speed with Fitaly was 74.34 wpm. Best speed with Graffiti was 49.44 wpm. Best speed with Qwerty was 47.05 wpm. Average speeds of entrants to the speed competition was 57.3 wpm (Fitaly Stamp), 51.03 wpm (Fitaly), 28.19 wpm (Graffiti), and 36.14 wpm (Qwerty). See the Fitaly site for details.

Problems with keyboards include needing a lap or a desk equivalent, tiny keyboards that are impossible to type on, and poor feel from keyboards.

Keyboards are not an ideal solution; they just seem to be the best we have at the moment. Remember that a keyboard need not be qwerty. Some people claim that chorded keyboards are the way to go, but most people are unlikely to accept them.

Best small palmtop keyboard I've seen to date is on the Psion 5.

Voice recognition technology isn't a total solution, as it isn't suited to noisy areas outdoors, nor quiet areas like libraries or lectures.

Voice notes can be helpful in some situations, but make sure there is some easy way to start the recorder function (the Psion 5 has external record buttons).


Summary - no such thing as too much.

Most people I talk to have contact files of at least 500 people, and many use multiples. I have several data files of over 100k. It wasn't even worth looking for a pocket computer until they started to have in excess of 1 megabyte of storage space.

Be warned that a megabyte of memory is not the same as a megabyte of user storage space. In particular, MS-DOS based computers use up to 640k of your memory as an area in which to run programs, so their effective storage space is enormously reduced from that written on the box. A similar problem may be present in Windows CE systems.


Summary - don't.

Devices that have a large number of functions, and a small number of keys have a real problem. You can't provide a unique key for each action. One trick is to remap the entire keyboard, according to which mode you place the device in. New users tend to find this a right pain. Find some other solution.


Summary - can you open an application, pull up a menu, then move to another application, and then return to your original place in the first application, file open and cursor in the same spot?

Psion 3 and 5 models do this. Some other products do not return to the same spot within an application when you switch. Franklin Rex won't do it, and I'm told the Palm doesn't do it.

PC Cards

Summary - great idea, but check compatibility first.

Custom cards, as on the Psion 3 series, guarantee that you pay a fortune for your cards. Reject these in favour of PCMCIA or PC Card or Compact Flash compatible cards. However, also test that the card you intend to use actually works - as standards go, PCMCIA sucks, and some Compact Flash cards give problems in some readers.

Even if your pocket computer has PCMCIA, it doesn't mean anything else can read it. Apple Newton cards don't seem to be readable on PC desktop systems. HP OmniGo 100 Geos files can be read on a PC, but GeoWorks on a PC does not appear to understand the contents. Check before you buy (if you can). Windows does not have support for obsolete PCMCIA SRAM cards.

Compact flash is getting very popular with digital camera makers, and appearing in new pocket computers. It will probably end up the standard for add-on memory storage. A lot of current PDA and palmtop computers are using compact flash. So far I've had no problems with it in my Psion 5, and Windows 98 notebooks seem to read it. Linux seems to provide excellent support, and on my Eiger ISA to PCMCIA adaptor was able to handle SRAM and Compact Flash. There have been some reports of compatibility problems.

PC Compatibility

Summary - desirable but not essential.

If the internals of your pocket computer are not compatible with a standard PC, then you get to buy all your software from a restricted range of probably expensive vendors. You can't use any handy tools that you use on a PC.

However, you don't have any choice now, because all the MS-DOS pocket computers are now off the market. The best of the breed (apart from the too small keyboard) was the HP100LX and HP200LX.

If you can find, and afford, all the software you will ever need for a non compatible model then that is fine. The Apple Newton is a good example of a system that takes advantage of new technologies without being tied down by an ancient architecture. You can get really good results this way. However, you should never be the first to buy new technologies. Maybe they won't work. If they work, maybe the application you need won't appear. Finally, maybe the company will give up selling that technology (large Japanese companies are very likely to give up anything that doesn't sell exceedingly well, and Apple gave up on the Newton just when they finally got it working properly).

Please note carefully that despite the hype, early "Windows CE" pocket computers are not in any way, shape or form actually compatible with Microsoft Windows (desktop version). Easy proof, just copy any Windows or MS-Dos application or data file from your desktop onto a PCMCIA card, and put it into a Window CE system. They will not be able to run it. And vice versa. They do have a limited form of data compatibility, which is made available via the file transfer software. This compatibility is much better from the Windows CE system than it is to the CE system (for instance, a equation in Word does not move correctly, nor do most Excel macros).

See also Data Compatibility.


Summary - if it doesn't print, forget it!

Several otherwise fine pocket computers on the market (the USR Palm Pilot, every Windows CE 1 except those from HP) can not print at all. They either have no printer port, or no printer software support. This is utterly useless, because you then have to depend entirely upon getting back to your office to get a quick printout.

My own preference is that the palmtop include an IrDA port (and I try to note who around me has IrDA equipped printers ... HP LaserJet 5P and 6P do, as do a few ink jet printers).


Summary - if it crashes, forget it.

An unstable operating system is a disaster. Will the pocket computer operate for months on end without crashing, and without losing work? Ones based on MS-DOS can easily be wrecked by untried software additions. I don't want to have to keep rebooting to keep the thing working; I expect it to run for months without problems.

Can you open another application while a dialog box is open. Does it give you hourglass icons and refuse to let you start something else until it is finished? I find that unacceptable.

It is totally unbelievable that any computer would require you to reboot after adding some application software.

Size and Shape

Summary - does it fit your pocket

If it isn't small enough, and smoothly enough shaped, it won't fit your pocket or bag, and will get left behind at your desk. This makes it no use as a personal pocket computer.

Small enough includes Psion 3 series, HP LX200, Palm Pilot, Roladex Rex ... and after that, most of them are too large.

Software Provided

Summary - usually not sufficiently powerful

Some widely touted systems, like Windows CE 1, Palm Pilot, some PIM based organisers, simply lack powerful software in some areas. They may provide a note taking editor, but it typically lacks spelling checkers, fonts, style sheets and other standard features. Or their PIM may have problems with flexible repeated appointments. See if you can set up an alarm for, say, the third friday of each month. Or they may lack a spreadsheet. In short, you should have a lot of power available immediately.

You also need to check whether you can get access to a good range of additional software for more specialist tasks. My own prejudice is that the system must have a programming language available so you can write your own applications if need be (that ensures other people will also write software).


Summary - if you can perceive a delay, it is too slow.

No, don't tell me how fast the system clock is. The real thing is whether everything you try to do happens quickly. Rule of thumb remains, if you can perceive a delay, it is too slow. If you get hourglass icons, it is too slow. Lots of slow computers can "feel" fast, if the software is correctly designed. Lots of "fast" computers can feel slow, if the software is not designed right. Try firing up the word processor to take a quick note. If you can't start adding your note in under a second, it is too slow. Try adding a name to the database. If it takes more than a second, it is too slow. Try making an appointment, with an alarm. Many, many well publicised pocket computers fail these speed indicators.

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