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PARTIAL WAIVER OF COPYRIGHT
All of the material in this patent application is subject to copyright
protection under the copyright laws of the United States and of other
countries. As of the first effective filing date of the present
application, this material is protected as unpublished material.
Portions of the material in the specification and drawings of this patent
application are also subject to protection under the maskwork registration
laws of the United States and of other countries.
However, permission to copy this material is hereby granted to the extent
that the owner of the copyright and maskwork rights has no objection to
the facsimile reproduction by anyone of the patent document or patent
disclosure, as it appears in the United States Patent and Trademark Office
patent file or records, but otherwise reserves all copyright and maskwork
rights whatsoever.
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to computer systems (and particularly to
small computer systems), and to methods for using them.
The innovations disclosed in the present application provide computer
systems (especially very small portable personal computers) which have
advantageous new capabilities. To better explain the significance and
advantages of these innovations, the following paragraphs (down to page 7)
will review some technological context. This technological context is not
necessarily prior art, but is intended to help in pointing out the
disclosed inventions.
Laptop and Smaller Computers
Portable personal computers were introduced in the early 1980s, and proved
to be very useful and popular. As this market has developed, it has become
increasingly clear that users strongly desire systems to have small
volume, small weight, physical durability, and long battery-powered
lifetime. Thus, small portable computers ("laptop" computers) have proven
extremely popular during the late 1980s. Users continue to demand more
features, longer time between recharges, and lower weight and volume. This
combination of demands is difficult to meet. Moreover, as of 1990, another
smaller generation of portable computers has begun to appear, referred to
as "notebook" computers. This smaller form factor will only exacerbate the
difficulty of the above tradeoffs.
Some Difficulties of Small Size
To meet the weight, volume, and power budgets of small portable computers,
much effort has been made to re-engineer familiar components, within the
limits of acceptable compromise with user comfort and convenience, to
attain the needed portability. For example, almost no laptop or notebook
computers have had more than two disk drives (typically one floppy drive
and one hard drive); the keyboards are much smaller than would be optimal
for touch typists; and the displays are much smaller than on common
desktop models.
Where such compromises are needed to attain the overriding goal of
portability, users readily accept them. However, if these compromises can
be avoided some of the time, it is highly desirable to do so. Thus, for
example, many users will "dock" their laptop or notebook computers, when
on their desktops, in order to use better peripherals (faster, larger,
more heavy-duty, and/or easier to use) than could be carried with the
portable computer.
Portable computers are inherently more susceptible than desktop computers
to accident, loss, and theft. Thus, if critical work is being done on a
portable computer, backup is even more of a necessity than with a desktop
computer.
The quantities of mass storage available on portables have steadily
increased, but the cost per byte of the necessary ruggedized drives
continues to be far above that of that of the drives normally used. This
disparity seems likely to continue. Similarly, although some small
portables use nonvolatile (or nonvolatized) solid-state memory to replace
disk drives, the cost per byte of such memory is likely to continue to
exceed that of conventional mass storage devices.
Laptops normally have a severely limited set of external ports. This
limitation is imposed by several factors: first, each external connector
takes up precious square inches of surface area. Second, each external
connector is a point of vulnerability to electrostatic-discharge-induced
component failure. Third, each external connector is a possible point of
entry for dirt and moisture. Fourth, in calculating the worst-case power
budget for a system, the possible power required by all connectors must be
considered.
Similar problems arise from the need for bus extension. Internal space is
not available for expansion cards, as in a normal personal computer; but
needs for expansion still exist. Some small computers have brought out key
bus lines into an external connector, but of course this is unwieldy.
Other small computers have sent signals out over a port to an
independently-powered extension bus controller with bus slots which would
emulate the computer's internal bus.
Continuing Advantages of Stationary Personal Computers
The capabilities and cost of both stationary and portable computers have
rapidly improved over the years. However, it is likely that stationary
personal computers will always have some advantages over lightweight
portables: it has always been true that, for a given price, stationary
computers have always had more computing horsepower, larger mass storage,
better displays, and better user interfaces (including keyboard, mouse,
joystick and/or track ball input devices). These advantages are due to the
necessary constraints (of weight, volume, power budget, and
shock-resistance, and environmental resistance) which necessarily must be
met by a small portable computer, and need not be met by a stationary
personal computer.
Use of Both a Portable and a Stationary Computer
As small portable computers become ever more common, an increasing number
of users prefer to use two computers: one for their desktop, and one more
for the road. This increasingly common pattern of usage is very convenient
for users, but also generates some problems.
One problem which arises is loss of file coherency: when a user edits a
file on his secondary machine, he must transfer that file back to his
primary machine before he again edits the same file on the primary
machine.
"Docking" a Portable Computer
Users find it very convenient to "dock" a portable computer on their
desktop, to a full-size keyboard and/or display. When a portable computer
is used in such a configuration, users will also wish to use many of the
peripherals (such as printer, modem, fax machine, tape backup devices, or
additional disk drives) which are easily available with a desktop
computer.
This problem becomes more urgent as useful amounts of computing power
become more available in physically small portable computers.
Thus, in general, as convenient as small portable computers are, there is
some difficulty getting data into and out of them. Usually the only
available data routes are through a modem or through the floppy drive.
(Some portable computers have LAN interface cards, but this is an
expensive option, and requires a compatible LAN to interface to.) This has
been recognized as a problem, and many vendors have offered external drive
connections for small portable computers.
Data Interchange with a Portable Computer
Portable computer users frequently desire to exchange data with desktop
computer systems. One of many ways to accomplish this data interchange is
to connect the portable computer to the desktop computer by means of a
cable. This cable typically connects the serial or parallel port of one
computer to the corresponding port of the other computer. Data interchange
is effected using complementary software programs resident on both
computers.
Several problems exist in this scenario. First, the typical desktop
computer has I/O ports located on the back panel of the housing. The
housing is commonly sited close to a wall or cabinet, or worse, on the
floor under or beside the desk. User access to the ports for the purposes
of connecting a cable is cumbersome, if not impossible. Further, the
required serial or parallel port on the desktop computer may already be
committed to other common peripherals, such as mice, printer, etc. In this
case several cables must be disconnected or connected to effect the link.
A second problem may exist in many cases. Often several cables must be
connected to the portable computer to provide data communications in
several formats as well as power system control, sequencing, and battery
charging. Each interface or power cable is typically unique, requiring the
user to perform several intricate manual activities every time the
portable computer is to be interfaced.
Typically, users requiring data interchange are not comfortable with
regularly re-configuring their computer system hardware. This is
particularly true if such reconfiguration requires unnatural physical
acts, such as crawling under a desk or leaning over a desk.
These are portable system expansion adapters in which the portable element
rests upon the adapter in a horizontal configuration, such that the
portable element's keyboard and display may be used in the docked
configuration. Electrical interface is generally accomplished by means of
a high density, high pin-count connector. Mechanically, the two elements
typically interface through cams, hooks, and/or latching mechanisms. (One
example of such a connection may be the Compaq LTE Docking Station, which
is hereby incorporated by reference.) Advantages of such arrangements
include: High data-rate interconnect; No user requirement to manipulate
cables; Portable computer's keyboard and display usable while interfaced.
Some disadvantages include: Connector/Mechanism Cost; Potentially low
reliability of high-density connector; Interface alignment is critical,
requiring potentially intricate user manipulations.
Innovative Computer System and Method
The present invention provides a new way to reconcile the demands and
capabilities of stationary and portable personal computers. The present
invention teaches a macro-system which includes at least one portable
computer and at least one stationary computer, and the stationary computer
system includes a docking bay in which the portable computer is physically
inserted whenever the user has returned with it to his primary work area.
This docking station includes contact probes which automatically make
contact to a small number of contacts on the back of the portable computer
whenever it is stuffed into the docking station. The portable computer
preferably includes soft power switch logic, so that an activation signal,
received when the portable computer is docked, can be used to wake up the
portable computer and bring it up active in a slave operating mode.
The combination of spring-loaded axially-moving pins, in the docking bay,
with flat contact pads on the portable unit provides a very robust
structure. This structure provides great ease of use, and good
reliability.
Appropriate software routines can then be triggered to maintain file
coherency. For example, a TSR program or background process on the
stationary computer can be used to sense whenever the portable computer
has been docked, and launch a file comparison process. This process can
compare all files with common path and file names, on the portable and
stationary computers, to see if any of them have more recent dates shown
on the portable computer. (This process can also compare the real-time
clock values, of the stationary and portable computers to correct for any
offset in real-time clock values.) Alternatively, of course, this file
comparison and update procedure can be modified in a variety of ways
familiar to designers and users of file management utilities. For example,
to limit the scope of comparisons (and therefore the time required for
automatic update), categories of files to be compared can be included or
excluded by path name or by suffix or otherwise. For another example, the
process can include a query which ascertains which portable computer has
just been docked, and the process can maintain a small data file of its
own listing time of last update for each possible portable computer, and
the process can then simply look for files on the portable computer which
have dates since the last update. Similarly, the updating in the opposite
direction (from the main stationary computer to the portable computer) can
be amassed by data file selection list, and also can be manually
triggered, when the user is about to undock or can be automatically
performed as a background process whenever the stationary computer is idle
after a file save has occurred.
For durability and environmental resistance, it is inherently desirable for
portable computers to fold up into some reasonably compact shape which
conceals vulnerable portions as much as possible. Thus, notebook computers
normally fold up, in a clam shell configuration, so that the display and
keyboard are on the inside of the clam shell, and protected, when the
notebook computer is closed. The present invention takes advantage of this
characteristic by docking the portable computer in its closed
configuration into the docking bay on the stationary computer.
No multi-pin connectors, such as are commonly used for cabling a data link,
are used in the presently preferred embodiment. Instead, spring-loaded
probe pins, in the stationary docking bay, are used to contact exposed
flat contacts on the back side of the portable computer. More precisely,
these exposed flat contacts are on whichever side of the portable computer
is to be inserted first into the docking bay. If the portable computer has
a handle, this would be the side opposite the handle.
Note that the present invention is not necessarily limited to "notebook"
portable computers. It can also be applied to "laptop" size portable
computers, or to "palmtop" or smaller portable computers. In particular,
the disclosed system is not necessarily limited to portable computers
which rely primarily on keyboard input. The disclosed system can also be
used with portable computers which use both keyboard and stylus input, or
to portable computers which use stylus input alone, or to portable
computers using other input configurations as such are developed.
In the presently preferred embodiment, the docking bay is a rectangular
parallelepiped, which includes internal ribs to guide portable computer
into its docking position with minimal friction. However, other
parallelepiped shapes can readily be substituted. In a further
alternative, the docking bay may have a wedge or pyramidal shape, if the
back portion of the parallel computer has a tapered wedge shape.
In any case, note that the interior of the docking bay must fit the
3-dimensional physical shape of the exterior of the portable computer.
Of course, different models of portable computers may have same external
shape, and thus be usable with the same docking bay.
Note also that (provided a portable computer has the accessible docking
contacts in the defined shape, with the defined electrical relations), the
only element which may have to be customized to a particular portable
computer model is the shape of the docking bay. However, this is simply a
piece of molded plastic. Therefore, sellers of portable computers which
include the contacts for such a "smart dock" can supply an appropriately
customized docking bay shell, if needed, to ensure that their portable
computer models will be compatible.
Some noteworthy advantages of the present invention include: docking
requires only a low insertion force; No Latches, Cams, or levers need be
operated for docking; the interconnect is a High-reliability Low-density
interconnect; the Pin (male) elements are protected by sleeve; the Pad
(female) elements on the portable unit extremely are extremely rugged;
cost is low; and the system is very convenient for the user.
ESD Protection
The contacts at the back of the portable computer, in the presently
preferred embodiment, are more exposed to electrostatic discharge (ESD)
than are the conductors in conventional stereo, parallel, keyboard, and
video connectors which may be found on the back of a normal portable
computer. Thus, in the presently preferred embodiment, additional
protection is provided against damaging internal electronic components by
ESD.
Serial port interface chips are preferably used, inside the portable
computer, for interface to these contact pads. Serial port interfaces
normally include significant ESD protection. However, if additional
protection is required, other known expedients can be used, such as
shunt-connected Zener diodes, series-connected resistors, and/or fast-blow
series fusing.
In addition, some mechanical protection against accidental fingertip
contact can be provided simply by placing low ribs around and between the
back contact pads.
In a further alternative embodiment, a trap door arrangement can be used to
selectively expose the back contacts only when the portable has been
inserted into its docking bay. However, the additional mechanical
complexity this entails is highly undesirable.
In the presently preferred embodiment, the docking bay includes feet which
support it in an upright position. Thus, the portable computer can be
inserted into its docking bay like a book into a bookcase. However, in a
contemplated alternative embodiment, the docking bay can be set to open
upwards, so that the portable computer is simply lowered into the docking
bay. Thus, gravity helps to maintain a good contact between the contact
heads on the back of the portable computer and the probe pins inside the
docking bay.
In the presently preferred embodiment, the portable computer can be
inserted into the docking bay in either of two orientations. This can be
accomplished in two ways. The preferred way is to include two sets of
probe pins, in complementary locations inside the docking bay, so that the
contact pads on the back of the portable computer will meet a set of probe
pins in either orientation. Alternatively, it would be possible to define
the location of the contact heads on the back of the portable computer to
be symmetric, with additional logic for ascertaining which orientation is
present and for rerouting signals accordingly. This is not preferred,
because it places additional constraints on the designers of portable
computers.
Note that if two sets of probe pins are used in the docking bay, the area
of the contact pads on the back of the portable computer must fall over
the axial center of the back of the portable computer, to keep the two
sets of probe pins separate. Note that also this double orientation
capability is an optional feature, which can be included in the docking
bays for some models of portable computer and not included in the docking
bays for other models of portable computers.
Note also that the location of the contact pads, on the portable computer,
is not necessarily on the back of the system chassis. For instance, on a
notebook computer with dimensions on the order of 7.times.10.times.2
inches, the keyboard will normally be oriented so that its width is
limited only by the largest available dimension of the system chassis.
Thus, the smallest of the six sides of the notebook computer will be the
two end sides to the left or right of the keyboard. One of these sides
will typically be taken up by a floppy disk drive, but otherwise these
sides are likely to be less intensely populated than the back of the
portable computer. Thus, for some models of portable computers, these
sides may be the most advantageous location of the contact pads.
In the simplest embodiment, data interfaced through the contact pins is
built around a serial data interface. Thus, signals routed to the back
contact pads will include the three serial lines (Rx data, Tx data,
ground), and preferably one pin for presence detect as well as a pair of
pins for handshaking signals (such as CTS/RTS).
Note that the mechanical arrangement prevents sideways forces from being
applied to the probe pins.
Preferably, the signals from the probe pins are brought into the host
computer through a serial port connector. A small amount of glue logic is
preferably used for presence detect; for example, a microcontroller in the
portable unit can implement both presence detect and power sequencing.
Alternatively, of course, in a motherboard which is designed from scratch
to accommodate this capability, a dedicated connector can be brought out
to the edge of the mother board.
Note that the axially-contacted pins used in the presently preferred
embodiment are not well suited for very high current density. Thus, for
applications which require higher current density (e.g. for rapid
recharging of batteries in a portable item), a conventional wiping contact
arrangement may be better. However, if needed for such applications, the
capability to manually connect a high-current contact for battery recharge
can be added to the simple drop-in signal contact arrangement of the
presently preferred embodiment. Alternatively, where a small amount of
charging current will suffice, it can be provided by multiple
axially-contacted pins connected in parallel.
BRIEF DESCRIPTION OF THE DRAWING
The present invention will be described with reference to the accompanying
drawings, which show important sample embodiments of the invention and
which are incorporated in the specification hereof by reference, wherein:
FIG. 1 shows how the portable computer, in the presently preferred
embodiment, fits into the docking bay.
FIG. 2 is another view of the portable computer being inserted into the
docking bay.
FIG. 3 shows the combination of stationary computer, portable computer,
docking bay, and permanent cabling.
FIG. 3A shows an EISA connector which provides space for insertion of up to
6 EISA bus master cards.
FIG. 3B shows how a combination I/O chip provides external interface
capability.
FIG. 3C shows a connector for a VGA daughterboard.
FIG. 3D shows a three-element EISA-bus chip set.
FIG. 3E shows a processor daughterboard which is accessed through a
connector.
FIG. 3F shows details of the main RAM.
FIG. 3G shows details of the video subsystem daughterboard.
FIG. 4 shows a perspective view of the notebook computer of the presently
preferred embodiment in the open position.
FIG. 4A shows the principal electronic components of hardware architecture.
FIG. 4B shows details of the connections of a microprocessor and a bus
controller.
FIG. 4C shows details of the connections of a video controller.
FIG. 4D shows details of the connections of a power management
microcontroller.
FIG. 4E shows details of the connections of a combination I/O controller.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The numerous innovative teachings of the present application will be
described with particular reference to the presently preferred embodiment.
However, it should be understood that this class of embodiments provides
only a few examples of the many advantageous uses of the innovative
teachings herein. In general, statements made in the specification of the
present application do not necessarily delimit any of the various claimed
inventions. Moreover, some statements may apply to some inventive features
but not to others.
FIG. 1 shows how the portable computer 100, in the presently preferred
embodiment, fits into the docking bay 110. This view includes a cutaway of
the docking bay 110, to show the positioning of the docking pins 112, in
the presently preferred embodiment.
FIG. 2 is another view of the portable computer 100 being inserted into the
docking bay 110. In this view, the contact pads 102 on the back of the
portable computer 100 are visible. Note that the contact pads 102 have a
geometry and spacing which is exactly complementary to the geometry and
spacing of the pins 112 in the docking bay.
In the sample embodiment shown, ten pads 102 and ten pins 112 are used, but
optionally this number can be increased or decreased.
The pads 102, in the presently preferred embodiment, are flat gold-plated
metallic contacts, of about 1 cm by 0.5 cm; but of course other dimensions
can be substituted.
The pins 112 are preferably spring-loaded pins, of the type known in the
electronics industry as "pogo pins." Such pins are very commonly used for
automated circuit board testing. These pins, in the presently preferred
embodiment, each have a contact area of about 0.005 in.sup.2, have a
travel of about 0.25 in, have a spring constant of about 10 oz.-force per
inch, and an initial spring preload of 0.5 oz.-force. Of course, these
specifics are merely illustrative, and can be varied.
The docking bay 110 is shaped to stop the inward motion of the portable
compute 100, when inserted, at a position which allows each of the
spring-loaded pins to apply a force of about 3 ounces-force when the
portable computer is fully docked.
In this embodiment, the docking bay 110 also preferably includes internal
ribs (not shown) which guide the portable compute 100, when inserted, with
low friction.
FIG. 2 also shows the cabling 114 which is routed to the pins 112. This
cabling is preferably connected to a serial port of the stationary
computer. In the simplest embodiment, no glue logic is used; but user
initiation is then required to commence a file transfer.
FIG. 3 shows the physical appearance of a sample combination of stationary
computer, portable computer, docking bay, and permanent cabling.
Sample Preferred Embodiment of Stationary Computer
The claimed inventions have been implemented in the context of an
80486-based 33 MHz EISA system (the 433DE.TM. model from Dell Computers).
That system is regarded as the presently preferred embodiment of the
present invention, and will be described as such here. However, it should
be understood that the disclosed innovations are also applicable to a vast
variety of other system configurations; in fact, the features described
are currently being designed into various other systems as well.
FIGS. 3A-3G are all parts of a single large drawing. (However, these
Figures are not all to the same scale.) These Figures show the key
components of the motherboard (system planar) and its daughterboards.
FIG. 3A shows the EISA connector 360, which provides space for insertion of
up to 6 EISA bus master cards (or ISA cards). This connector permits EISA
accessories to access the SD, SA, and LA bus lines, (These are all
conventional EISA bus lines. For more detail on the EISA bus, see, e.g.,
Dowden, INSIDE THE EISA COMPUTER (1990), which is hereby incorporated by
reference, as well as the needed bus control signals, and also includes
lines for receiving .+-.5 V and .+-.12 V power supply voltages.
FIG. 3A also shows the header 362, which is connected to the IDE drive
cable inside the system chassis. This connector is linked to the X-bus
through a buffer, and can also communicate with the system bus through a
transceiver. This connector also receives a drive-select signal CS0/1*
from the combination I/O chip 334 shown in FIG. 3B.
FIG. 3B shows how the combination I/O chip 334 (which, in the presently
preferred embodiment, is an 82C106) provides external interface
capability, through parallel (printer) port 364, two serial ports 365, a
mouse port 361, and a keyboard connector 363. The combination I/O chip 334
also interfaces to a floppy disk drive controller chip 332 (which, in the
presently preferred embodiment, is a PCB477). Floppy disk drive controller
chip 332 connects to floppy header 366, to which a ribbon cable is
connected to communicate with the floppy disk drives inside the system
chassis.
FIG. 3B also shows a header 367, which is used to connect to the
SmartVu.TM. diagnostic display (The Smart Vu.TM. device is a very small
character display in the computer chassis, which is used, under low-level
control, to output status and diagnostic messages, and to the speaker.
FIG. 3B also shows the X-bus lines XA and XD. As is conventional, these
lines are connected to the system bus through buffer and transceiver
logic. The X-bus may be thought of as an isolate portion of the system
bus. Unless communication to devices off the motherboard is required, the
X-bus-to-system-bus transceivers do not have to be turned on.
FIG. 3C shows the connector 351 for the VGA daughterboard. Note that the
system bus lines are routed to this connector, but that VGA control
registers 353 are connected to the X-bus. System configuration element 343
is connected to bus control lines, but is also accessible from the X-bus.
FIG. 3C also shows the boot memory 340, which, in the presently preferred
embodiment, is a sector-erasable flash EEPROM. This is connected to the
X-bus and to a special access line FLHA. Optional EISA configuration RAM
342 (backed by battery 370) is also connected to the X-bus as is optional
boot EPROM 344. (This configuration is preferably used to provide a
capability for user updates of the BIOS, as detailed in U.S. patent
application Ser. No. 07/706,750, filed May 29, 1991 and now abandoned and
entitled "Computer system with Restorable Basic Firmware" (DC-200), which
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