CompactFlash, SmartMedia, Memory Sticks, MultiMediaCards, Secure Digital. It seems there are almost as many different types of Storage cards as there are handheld computers. For the first time PDA buyer, or even the experienced user looking to upgrade, this just adds to the complexity of deciding which Pocket PC or Palm Powered handheld to share the intimate details of your life with.
Well, maybe we can help, my friend.
In this Brighthand Buyer’s Guide to Storage Cards, we’ll take a look at several of the popular storage card options on the market. We’ll cover their basic pros and cons, along with what you should know about them when you buy your next PDA.
But first let’s summon up the spirits of storage past for a bit of a history lesson.
A brief history of data storage
Here’s a basic question: Does a computer really need a way to store data?
The answer is no, not really. After all, the three basics of computing are input, processing and output. There’s nothing in there about storage. But from a purely practical view, a method for storing information can be critical. Otherwise, each time you decide to run an application you’d have to enter the data you wish to process AND the program code that processes it. Imagine having to enter the hundreds of lines of code for Microsoft Excel every time you wanted to create a spreadsheet.
Not very efficient, is it?
Charles Babbage faced that problem in the 1830’s while working on an invention he called the Analytical Engine. He turned to a method invented by Frenchman Joseph-Marie Jacquard for his automated weaving loom. Jacquard used perforated cards to convey the weaving pattern to the loom. Babbage figured that the same punched card method could be used in his early computer.
MIT’s Herman Hollerith went on to perfect its use in 1890 for storing census data for the U.S. Census department and we had our first true storage media. But enough about the past.
Since then we’ve moved from purely mechanical forms of storage, such as the punched card and its cousin punched tape, to electromagnetic and other forms of storage. Today we have magnetic disk, magnetic tape, solid state disks, optical disks, and holographic storage.
Plus, we’ve now got storage inside our computers, on computer chips, as well as on separate storage devices and media, such as disk drives and CDs. This internal storage, or memory, comes in two flavors: ROM and RAM.
So let’s start there.
What’s all this about "flash" ROM?
ROM is short for Read-Only Memory. It refers to a memory chip that is used to permanently store instructions and data, without requiring power. Its contents are written to the chip at the time of manufacture, but cannot be changed thereafter (well, that’s almost true)–that’s why they’re called read-only.
In most cases, the only way you can change the contents of a standard ROM chip is by replacing it, a very important issue when it comes to PDAs. For instance, most handheld computers store the operating system in ROM, quite different from desktop and laptop computers which store it on their hard drives and load it into memory each time you boot up. In other words, for PDAs, the operating system is embedded in the device.
So, rather that allowing a consumer to upgrade his device to a new release by purchasing some software and installing it (as is the case with most PCs), a PDA buyer must replace the ROM chip in order to upgrade the OS to a new release. That is, if the device manufacturer provides a ROM upgrade, which often is not the case.
This is true of the original Palm Pilots (1000, 5000, Personal, and Pro) and the Handspring Visors, which have their OS and built-in applications in ROM. In order to upgrade the version of Palm OS in these devices, a consumer must replace the memory card, which contains the ROM chip.
An alternative for PDA manufacturers (remember I said "almost true" above) is to use "flash memory" ROM chips, which can be upgraded programmatically rather than requiring replacement. In fact, its name was coined by Toshiba because it could be erased "in a flash." Still, like standard ROM, flash ROM is non-volatile, meaning it does not lose its contents when power is removed.
Palm switched to flash ROM starting with the Palm III and Compaq was the first Pocket PC to offer it. But despite its obvious advantage many device manufacturers still do not use flash ROM for one simple reason: cost. Standard ROM is less expensive than flash ROM.
However, there’s a basic practical truth about flash ROM. It’s important only if you are fairly certain that you’ll be upgrading the operating system on your device at some time, otherwise it doesn’t really matter.
The more RAM the better, but it’ll cost you
RAM, meanwhile, is short for Random Access Memory. It is a group of memory chips which function as the computer’s primary workspace. It is used to hold programs and data files. In many operating systems, RAM is also called "main memory."
RAM is different from ROM in that it is volatile. In other words, it requires power to maintain its contents. Just pull the batteries out of your device for a while and you’ll see the practical implications of this. Still, RAM has something over ROM: its contents are easily modifiable.
Bottom line on RAM is, the more RAM the less you’ll have to rely on storage cards, and the better and faster you’re device will often perform. Still, storage is storage, and a storage card is as good as RAM for storing data.
Cards, cards, and more cards
Now that we’ve spoken to the spirits, and gotten the meaning of ROM and RAM out of the way, let’s look at your options.
It all starts with PC Cards, commonly referred to as PCMCIA cards, which came about in the late 1980’s as laptop computers and mobile computing became popular.
PC Cards are credit card-sized integrated circuit devices that are rugged and relatively low-power (as compared to typical PC storage and I/O peripherals). This makes them perfect for, among other things, storing data that you’d like to take with you.
PC Cards are manufactured by hundreds of manufacturers around standards developed by the Personal Computer Memory Card International Association (PCMCIA) and they come in three official (Type I, II, and III) and one unofficial (Toshiba’s Type IV card) types. PC Cards are 16-bit plug-and-play devices measuring 3.37" long by 2.126" wide. They use a 68-pin connector, with cards being the female end of this pin-and-plug interface.
Several models of Pocket PCs can use PC Cards, although only the UR There @migo can do it without the use of an expensive add-on accessory, such as an expansion pack or sleeve.
Palm III users may one day be able to use PC Cards using The Parachute (pictured above). The Parachute is a slim, clip-on PC Card slot for Palm III devices that uses the RS-232 serial port, so it is likely to be slow and therefore suited more for low-speed I/O devices than memory. However, I wouldn’t hold my breath. We’ve been waiting for this for more than two years now and it doesn’t appear any closer to reality than it did back then.
CompactFlash storage cards
CompactFlash (CF) storage cards, first introduced in 1994 by SanDisk, are the most widespread removable storage devices found in PDAs. They are fast, lightweight, matchbook-sized removable mass storage devices that use flash technology, a non-volatile storage solution that can retain data indefinitely, even without power.
They can be used in a variety of consumer devices, including digital cameras and handheld computers. In fact, CompactFlash is supported in most platforms and operation systems that support the PCMCIA ATA standard.
CompactFlash storage cards for handheld computers are available from more than 40 companies, in capacities up to one gigabyte, and costing on average between US$0.70-US$1.40 per megabyte.
While CompactFlash storage cards are more expensive than conventional disk drives, they do have several advantages. For one thing, they are solid state devices, meaning they contain no moving parts. This provides greater data protection and less chance of mechanical problems.
Also, CF cards use minimal power and are rugged. They run at 3.3V or 5V with a single power supply and consume less than five percent of the power required to operate a conventional disk drive. And CF cards can typically withstand a 10-foot drop. With typical usage, a CF card can last more than 100 years with no loss or deterioration of data.
However, programs cannot be run directly from CompactFlash storage cards. Instead, they are loaded into RAM for execution. This results in a minimal delay over programs that reside in RAM.
The connector used with CompactFlash is similar to the PC Card connector, but with only 50 rather than 68 pins. Still, it conforms to ATA specs and can be easily slipped into a passive 68-pin Type II adapter card that fully meets PCMCIA electrical and mechanical interface specifications.
PDAs used in: All Pocket PCs (Compaq iPAQ Pocket PC using CompactFlash or PC Card Expansion Pack), HandEra 330, Handspring Visors (using MemPlug Springboard CompactFlash adapter)
Largest size: 1 gigabyte
Cost per megabyte: $0.70 – $1.40
Pros: Best combination of form, function and price
Cons: Not as small as MMC and SD cards
IBM, inventors of the Winchester magnetic disk technology, have taken disk storage miniaturization to new levels with its 170 MB, 340 MB, 540 MB and 1 gigabyte microdrives. These matchbook-sized CompactFlash devices contain an actual mechanical disk drive, not flash memory chips.
The upside is that they cost less than CF storage cards, generally between US$0.25 and US$0.40 per megabyte. However, the downside is that they draw more power and generate more heat. Also, since they have moving parts, they’re likely to experience more mechanical problems than CompactFlash storage cards.
Springboard storage module
HandSpring introduced an expansion method with its Visor line of Palm OS-based PDAs called Springboard. Springboard resembles the cartridge and modular connector system used in the Nintendo’s GameBoy systems.
One of the first Springboard modules to be released was the 8 megabyte Flash Module (US$79.95). It uses non-volatile flash ROM, so it can be removed without losing its data.
On the technical side, Springboards use a 16-bit interface (SmartMedia and Compact Flash have 8-bit interfaces), so they have the highest bus speed.
PDAs used in: Handspring Visor handhelds (Visor Edge requires Springboard adapter)
Largest size: 16 megabytes
Cost per megabyte: $3.75 – $10.00
Pros: True plug-and-play (i.e. no drivers need to be installed)
Cons: Expensive and non-standard (cannot be used in other devices)
Sony’s Memory Stick
Smaller than a stick of gum, Sony’s Memory Stick is currently used in several consumer products, including digital cameras, audio devices and more recently its Palm OS-based Sony Clie handheld computers.
Memory Sticks are currently available in capacities up to 128 megabytes and cost between US$0.60 and US$1.90 per megabyte. It uses a 10-contact connector and can read data at speeds up to 2.45 MB per second.
But some industry folks wonder whether other PDA Manufacturers would ever go with Sony’s Memory Stick. After all, would it really want to have a critical component of its device produced by a direct competitor?
MultiMediaCard and Secure Digital Cards
MultiMediaCards and Secure Digital cards are lightweight, postage stamp-sized storage cards that also use flash memory. They are currently available in capacities up to 512 megabyes (but are expected to grow to 1 gigabyte before the end of the year) and can be used in most Pocket PCs (although most only support them as storage cards), newer Palm models (m500 series, m130, i705) and the HandEra 330.
MultiMediaCards and Secure Digital cards (which provide for secure distribution of content, such as digital music and electronic books) use 7 metal connector contacts rather than pins-and-plugs so they are less likely to be damaged in transport or insertion and removal.
PDAs used in: Most Pocket PCs, newer Palm models (m500 series, m130, i705), HandEra 330
Largest size: 512 megabytes
Cost per megabyte: $0.60 – $1.50
Pros: Smallest and lightest of all removable media
Cons: New to the market, so it’s just gaining acceptance
SmartMedia Cards are slightly longer but significantly thinner versions of CompactFlash cards. They measure 0.76 millimeters thick (about 1/4 that of a CF card), weigh in at only 2 grams. SmartMedia Cards have connector contacts rather than pins and draw 3.3V of power.
Like CF cards, SmartMedia Cards use flash memory chips for storage, but unlike CompactFlash they do not have a controller on board; the controller is part of the slot built into the unit.
Currently, none of the Pocket PCs or Palm OS devices support SmartMedia Cards, although there is a SmartMedia SpringBoard adapter for Handspring Visor available from MemPlug.
However, the axxPac (see picture at right) from AMS Software & Elektronik GmbH is a snap-in module that fits into the expansion slot on the Palm IIIx and enables it to use SmartMedia Cards. AxxPac (US$89.99) consists of a replacement case back that allows SmartMedia Cards to be inserted into a slot created in the side of the device.
What’s in the cards?
Well, my friend, I hope we’ve helped you in your quest for understanding. It’s likely that you’ll continue to have some variety in your life, at least in your choices of PDA Storage options. However, we see Secure Digital or MemoryStick in your future.
Madame Brighthand believes that Secure Digital will make tremendous inroads over the next three years and bypass CompactFlash as the leader by 2005. MemoryStick usage will also grow as Sony promotes its use across its entire consumer products line.
And then there’s optical and holographic storage. Well, maybe that’s a bit further into your future. We’ll save that for next time.