BBS in a Box 2/BBS in a box - Trilogy II.iso/Files/Newton/Util/Newton Stuff/PCMCIA Info

Text File | 1993-08-04 | 9.6 KB | 161 lines | [TEXT/MSWD]

PCMCIA: The New Peripheral Standard
by Wayne Yacco

as appears in Issue #14, Sept/Oct 1993 PEN Magazine
copyright (c) 1993 PenWorld, Inc.
Call (800) 383-PENS, fax [phone] or email 71333,124 for
complete subscription information.

    The original desktop computers distributed control of
computing intelligence to the local user.  So, they were dubbed
personal computers.  When compared to the centralized mainframes
and minicomputers that preceded them, they were.  Personal digital
assistants, personal mobile communicators, and hand-held computers
take the idea of personal computing to another plateau.
    It's too bad "PC" has been co-opted by that earlier usage.  The
terms that have been proposed as alternatives to "PC" just don't
work.  Personal digital assistant, for example, smacks of redundancy-
-unless you expect analog versions to appear.  It's too long and
awkward too.  We need a term with immediacy--something like
intimate computer.  It's a good choice for several reasons.  It's short.
It conveys the ever-so-close relationship of a machine you write and
draw into, message with, and then stick in a pocket.  And it's
abbreviation, IC, already designates the large complex chip into
which all of this functionality is quickly converging.  Watch out, Dick
Tracy, you'll be talking, and computing, into your lapel pin soon.
Eventually, there will be the ultimate IC, the integral computer that's
surgically implanted into your grandchildren just before they're old
enough to verbally command it.
    This column is about the very next step on the way to that final
down-sizing: the PCMCIA (Personal Computer Memory Card
International Association) card.  PC Cards bring the functionality of
their full-size ISA, EISA, and MCA counterparts down to so few chips
that they can easily move between your wallet and your intimate
computer.  They're called PC Cards, but they are IC cards in every
sense.
     PCMCIA began only a few months ago as a way to interface
storage cards, but has quickly evolved into a new bus specification
for credit-card-sized peripherals.  With it's support for I/O, the new
PCMCIA, version 2, specification can open the smallest machine to
add-ons of all kinds.  Cards provide communications, connectivity,
interfaces, both solid-state and rotating storage, a host of memory
devices (flash, one-time-programmable, and static), and a rich
variety of other options.  It's the stuff that enables a general-purpose
computer to support all manner of vertical niches.  PCMCIA examples
already include products like Proxim's RangeLAN, a spread-spectrum
wireless network adapter.  Toshiba is shipping a card that encrypts
data, and makes access to it impossible without a password.  Toshiba,
and a few other vendors, are also shipping a SCSI adapter on a
PCMCIA card.  Competition among the many vendors shipping
memory, modem, and network-adapter cards is brisk.  Modem-
maker Megahertz is already making one that's completely self-
contained.  Consider that most pen-based machines are presently
employed in vertical applications, and it's easy to see that PCMCIA is
the spark that's going to fire up those markets.
    The time is definitely right.  Cards designed for the current
spec are increasingly compatible with new machines.  This has come
about, in part, from new hardware glue: the Intel 80365, the
Databook DB86082, and similar ExCA interface controllers from
several others.  ExCA is a functional spec--not a register-level
interface--for which Intel, Databook, and others have successfully
completed the Socket Compatibility Test..  Whichever glue chips a
host manufacturer chooses, all provide conformance to the PCMCIA
spec in a module the vendor can easily plug into computer designs.
    Software for the chips may be supplied by the silicon foundry:
Databook supplies all the necessary code.  Or it may be supplied by
third parties as is Intel's Card Services software.  This is important,
because in some early implementations, host vendors haven't always
written their code according to the PCMCIA spec.  In the name of
expediency, they have sometimes employed hardware-dependent
code.
    Megahertz vice president Steve Aldous recalls when the first
Intel modem cards landed on shelves.  Since it was then the only
card on the market, he says, some machines were built around its
silicon.  "Gross violations of PCMCIA rules resulted," maintains
Aldous.  Some systems actually looked for the Intel name in a chip,
and wouldn't enable the card if they didn't find it.  The Toshiba
T3300 gave Megahertz difficulties, because it expected a card to
decode all the address lines, as Intel does, and wouldn't allow the
PCMCIA-approved alternative of using a select line.
    PC Card LAN adapters, which typically require the end user to
configure the card and socket with an "enabler" program, are another
example.  A few enablers still talk directly to the controller's
registers instead of to PCMCIA interfaces.  Fortunately, the industry
is rapidly moving away from such dependence by following new
specs called Card Services (CS) and Socket Services (SS).  "The
chances of plug-and-play today are much higher than they were a
year ago, even six months ago," Aldous says.
    Card and Socket Services provide specifications to which
drivers can be written.  Tom Mitchell, National Sales Manager for
Proxim says, "We take advantage of Card and Socket Services to
expand our compatibility with different products."  Not all card
vendors do though.  Some fail to provide complete information in the
on-card Card Information Structure (CIS) header which is supposed
to identify the card's requirements.  When information is incomplete,
hosts may still be able to support many PCMCIA compliant cards
with a common driver by detecting the card and filling in the missing
information.  For example, hosts are able to support fax-data modem
PC Cards which employ the Hayes modem interface or other popular
models with well-known requirements.
    Unknown cards can also be handled another way, under the
new specification, by allowing drivers stored on the cards themselves
to be downloaded by the host.  If card makers adopt the practice of
storing drivers on their products, it can altogether eliminate the need
for hosts to recognize them, or to supply users with loadable driver
software.  However, this solution requires a complete PCMCIA
software package, and complete implementations are only now
coming to market.
    Not all card vendors have yet adopted fully successful
strategies.  Mitchell admits that Proxim occasionally has run into
minor glitches that have had to be worked out with its host-side
partners.  However, Mitchell credits the specification for keeping the
process simple enough to work out the details over the phone.  "The
problems that we've seen have been easy to conquer," he says.
    Daniel Sternglass, Databook chairman, a member of the PCMCIA
board, and chairman of its Host Compatibility subcommittee,
cautions: "Machines that claim PCMCIA compatibility may not have
Socket Services or Card Services, because there are not yet PCMCIA-
sanctioned compliance criteria."  Yet, by using recognition techniques
and generic-card handling, he says that many of these systems still
handle a wide range of cards.  Sternglass recommends shopping for
host systems based on PCMCIA software that includes Card and
Socket Services, and that come from a reputable supplier.
Regrettably, compliance is not easily detectable by end users.  On the
positive side, CS is upgradeable.  SS may be, too, if the machine's
BIOS is.  SS code can even be stored on a hard disk, and run from
RAM, when it's not required to boot the machine.
    While vendors work these issues out for themselves, PCMCIA
continues its shake-down cruise.  Luckily, PCMCIA compatibility is
accelerating faster than the evolutions that produced standard
emulations of the IBM PC BIOS for systems, the Hayes AT-command
language for modems, and the H-P Printer Command Language (PCL)
for printers.  In fact, PCMCIA already seems more compatible than
SCSI, which still requires installable drivers for every machine, and
sometimes even requires different removable media--even on
identical hardware when its sold under different brands.  PCMCIA
should soon reach the relatively trouble-free state of such successful
standards as PostScript and Ethernet.  When the final bugs are
worked out, survivors among the early participants will reap large
rewards.  Survivors?  You know what they say about pioneers.
They're the ones with the pointy ISO flowchart symbols for off-page
connections in their backs.
    PCMCIA still has a nagging complication in the difference
between compliance to the specification and implementation of it.
For example, not all machines supply both five and twelve volts.
And there's a limit to the current that smaller machines can supply.
Some machines will always be designed for applications that don't
call for a full implementation, and not every system will be able to
program flash memory or run a hard disk.  Thus, not all cards are
going to work with all machines--even when the card conforms to all
parts of the specification.
    Nevertheless, it does seem that most compatibility issues have
been resolved, or are resolvable.  I'll monitor PCMCIA's progress by
conducting practical compatibility trials and reporting the results in
this column.  Next issue, I'll continue this column with thumbnail
reviews of several cards that, if not exactly unique, are at least
representative of less-common offerings.  It will include those I've
already mentioned, plus one or two others.  And I'll have a
comparison table of many additional PCMCIA products.

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