Abstract:
A computer system has a removable module that contains a processor, other electrical components, and a battery. When the module has been removed from the computer system, the processor runs an application that interacts with the electrical components in the module to provide stand-alone functionality. When the removable module is in the computer system, the module is accessed by the computer system to cause the computer system to perform some of the functionality provided by the module. The functionality provided by the removable module includes receiving emails, displaying an appointment calendar, displaying a contacts listing, providing audio content, providing cellular telephone service, obtaining a video image, providing biometric identification information, sensing position, and displaying a television picture.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims the benefit of the filing date of U.S. Provisional Application No. 60/504,165 entitled SOFTWARE AND HARDWARE FEATURES FOR MINI-PC, filed Sep. 18, 2003, which is incorporated herein by reference. 
     
    
     FIELD  
       [0002]     This relates generally to processor-based systems, and more particularly to an electronic device having a removable module that can be used either as a part of the electronic device or by itself in a stand-alone manner.  
       BACKGROUND  
       [0003]     Electronic devices such as personal computers have become indispensable tools for business and personal use. In addition to a wide variety of applications that may be run on a personal computer, personal computers also serve as communications terminals for access to the Internet. Portable personal computers, generally known as “laptop” or “notebook” computers, have become increasingly popular because their portability allows access to the wide variety of computer applications when traveling, such as on airplanes. However, although continued progress has been made in reducing the weight and bulk of portable personal computers, they are still too large and heavy to be easily carried in many instances.  
         [0004]     The functionality of portable personal computers is also sometimes limited by the number of hardware components included in the computers. However, the functionality of such computers can be increased by the use of removable modules that can be received by the computers. For example, many portable personal computers have an extra bay that can receive a floppy disk drive, a second hard disk drive, a CD-ROM or DVD drive, an extra battery, etc. Similarly, a portable personal computer can be provided with a wireless receiver, a global positioning system (“GPS”) receiver, a TV tuner, etc. by inserting an appropriate card into an externally accessible slot. Although these modules can improve the functionality of portable personal computers, they cannot be used, and thus perform no useful function, when they are removed from the computers.  
         [0005]     Another limitation of conventional personal computers is the inability to use them to instantly review information, such as to look up a phone number or an address. Before the computer can be used to access the information, the computer must be turned on and then “boot up” by running an initialization sequence and loading an operating system. This process can take a considerable period of time. Furthermore, it is generally necessary to open up the portable computer to turn it on and access the information. It can be difficult to perform this function under certain circumstances, such as when driving a car or sitting in the small confines of an aircraft seat.  
         [0006]     Various devices have been developed to address these and other limitations of conventional portable personal computers, such as laptop and notebook computers. The most prevalent of these devices is the personal digital assistant, or “PDA,” which provides some of the functionality of a portable personal computer without the size and weight of such computers. This limited functionality generally includes an appointment calendar, an address or contact list, a task list and email capability when coupled to a suitable communication link, which may be wireless. In some cases, a cellular telephone is built into the PDA, and various applications having limited functionality, such as spreadsheets and word processors, are also available. PDAs offer a convenient means of using the limited functionality that they offer because it is not necessary to open a cover to view their display screens. Furthermore, there is minimal delay in accessing PDAs because their operating system remains stored in random access memory when the PDA is turned off so it may be executed by an internal processor as soon as power is applied to the processor. It is therefore not necessary to wait for a boot sequence to execute and an operating system to be loaded. When the PDA is turned off, power continues to be applied only to essential circuitry like a volatile random access memory, thus preserving the useful life of an internal battery before recharge is needed.  
         [0007]     Although PDAs have been very successful in making limited computer functions conveniently available to users, they do not provide all of the functionality and ease of use of a portable personal computer. As a result, business travelers and others often buy and transport with them a PDA and a personal computer.  
         [0008]     The usefulness of a portable personal computer can often be enhanced by coupling the computer to other devices. For example, a portable personal computer can be provided with wireless communication capability by coupling the computer to a cellular telephone. Although communications capability can be provided by other means, such as by coupling the personal computer to a wireless adapter, a cellular telephone is often indispensable for voice communications. Therefore, travelers frequently buy and transport with them a cellular telephone for use in voice communications and to enhance the utility of their portable personal computers.  
         [0009]     Other electronic devices are also frequent travel companions for business and personal use. For example, a digital camera is useful in both business and personal travel. By coupling a digital camera to a portable personal computer, image files stored in the camera can be downloaded to the computer for storage. Images from the stored image files can then be edited on the computer using commercially available photo editing applications. Video cameras are sometimes built in to portable personal computers, and they could be used to capture digital images. However, the weight and bulk of portable personal computers makes them difficult to use and carry for the purpose of taking photographs. As a result, a person traveling with a personal computer who desires to take photographs is likely to bring with him or her a stand-alone digital camera.  
         [0010]     Audio players, usually employing an MP3 decoding and playback capability, are also frequent companions of business and personal travelers. While a personal computer can store and play back MP3 and other audio files, it is often not practical to carry a portable personal computer when engaging in some activities. For example, while recreational runners frequently carry MP3 players with them while running so they can listen to music, it would be impractical to carry a personal computer while running. As a result, it is often desirable to have an audio player even if a portable personal computer is available. The same considerations apply to portable DVD viewers.  
         [0011]     In summary, there are a large number of very useful electronic devices that can be advantageously used with portable personal computers. Although these devices could be built into portable personal computers, doing so would greatly detract from the practical utility of such devices. Thus, one sees or can expect to see “well-wired” business and personal travelers carrying most or all of a portable personal computer, a PDA, a cellular telephone, a digital camera, a music player, a DVD viewer, and whatever new electronic device that is introduced in the future. The difficulty carrying all of these devices, as well as the cost of buying them, threatens to limit their usefulness.  
         [0012]     There is therefore a need to take advantage of the usefulness of electronic devices that can be used with a portable personal computer without the expense and transportation difficulties of obtaining a large number of such devices and without the difficulty of use that would be created by using them as part of a portable personal computer.  
       SUMMARY  
       [0013]     One preferred aspect provides an electronic processor-based device, such as a portable personal computer, that is adapted to physically and electrically receive a module that provides the device with additional functionality. The module can provide the device with all or some of the following functionality: cellular telephone, personal digital assistant (“PDA”), wireless communications through WiFi, Bluetooth or other protocol, global positioning system (“GPS”) to provide position information, digital camera, audio music player, DVD viewer, TV tuner, satellite radio, bio-identification, or other function that is useful to have with the electronic device. In addition to being functional with the electronic device, the module is also functional apart from the electronic device and thus usable in a stand-alone manner. Therefore, the module can be used without the weight, bulk and possibly limited power consumption of the electronic device. The module has its own processor and associated electronic components, and it is powered with its own battery, which may be recharged by the electronic device, to allow it to be used in a stand-alone manner. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a front isometric view of a computer system according to one embodiment showing a display lid in its open position.  
         [0015]      FIG. 2  is a top plan view of the surface of the display lid of the computer system of  FIG. 1 .  
         [0016]      FIG. 3  is a rear isometric view of a rear panel of the computer system of  FIG. 1   
         [0017]      FIG. 4  is a hardware system block diagram of one embodiment of the computer system of  FIG. 1 .  
         [0018]      FIG. 5  is plan view of a module that can be removably received in the computer system of  FIG. 1  according to another embodiment. 
     
    
     DETAILED DESCRIPTION  
       [0019]     A computer system  10  according to one embodiment is shown in  FIG. 1 . The computer system  10  has a “clam shell” structure formed by a lid  12  pivotally mounted to a chassis  14  at one edge  16 . A keyboard  20  covers substantially the entire inner surface of the chassis  14  except for an area occupied by a touchpad  22  pointing device. A main display  24  covers substantially the entire inner surface of the lid  12 . The computer system  10  is turned on by pressing an appropriate key on the keyboard  20 , and the keyboard  20  is used to enter alphanumeric data. Although the computer system  10  may be substantially the size of a conventional notebook computer, i.e., on the order of 250 mm by 300 mm in plan form, it is preferable only slightly larger than a conventional PDA, i.e., on the order of 100 mm by 150 mm with a thickness of about 25 mm.  
         [0020]     With reference to  FIG. 2 , the outer surface of the lid  12  includes a removable module  28  that includes an auxiliary touch-screen display  30  and a membrane keypad  34 . Shown on the display  30  are the current date and time  32 , status icons  36 , including status indicators showing the number of new email messages, the charge status of an internal battery, and the signal strength for an internal cell phone application. The touch-screen display  30  also includes an icon  40  for accessing the “Inbox” of an email application, an icon  42  for accessing a contacts application, an icon  44  for accessing an appointment calendar application, an icon  46  for accessing an audio player application, an icon  48  for accessing an voice memo application, an icon  50  for accessing a modem, an application  52  for locking the system, and an icon  54  for turning off wireless functionality when flying in an airplane. The functions represented by each of these icons  40 - 54  can be selected by pressing the icon on the touch-screen display  30 . The particular icon  40 - 54  that is selected is shown in the display  30  at  56 .  
         [0021]     The keypad  34  includes directional keys  60   a - d  that perform different functions depending on which application is being accessed. The directional keys  60   a - d  are used to move a cursor up, to the right, down, and to the left, respectively, when alphanumeric text is shown in the touch-screen display  30 . When the audio player application is active, the directional keys  60   a,c  are used to increase or decrease the volume, respectively, and the directional keys  60   b,d  are used for respectively moving forwardly or a rearwardly in an audio selection. The directional keys  60   a - d  surround an Enter key  62  that is used in a conventional manner.  
         [0022]     The keypad  34  also includes a menu key  66  that causes menu items to be shown in the touch-screen display  30 , a home key  68  that causes the display  30  to show the icons  40 - 54  illustrated in  FIG. 2 , an “Esc” or cancel key  70  that is used to cancel a current selection, and an Enter key  72  that essentially performs the same function as the Enter key  62 . The key  72  and key  70  can also be used as “call” and “end call” buttons, respectively, when the module is used to implement telephone applications.  
         [0023]     Also included with the keypad  34  are three audio control keys that are used when the audio playback application is active. These audio control keys are a key  80  for selecting a previous track, a play/pause key  82 , and a next track key  84 , which are used in a conventional manner.  
         [0024]     With further reference to  FIGS. 1 and 2 , the computer system  10  also includes a side wheel  86  (shown in  FIG. 1 ) mounted on the side of the computer system  10  that can be rotated in up or down directions by manipulating the wheel  86  with a finger. The side wheel  86  allows a user to scroll through menu items shown on the touch-screen display  30  when either the menu key  66  or an application running on the computer system  10  displays a menu. The side wheel  86  can also be used for other functions that are supported by applications running on the computer system when the computer system is open and powered, such as a “zoom” control in certain applications to change the scale at which an item is shown on the main display  24  or the touch-screen display  30 . Finally, the side wheel  86  may be used to configure the computer system  10 , such as to adjust the contrast of the main display  24  and the touch-screen display  30 , to toggle the touch-screen display  30  on and off, to control the volume of internal speakers, etc. The side wheel  86  can also be pressed inwardly along the axis of rotation to generate a key click, which is generally used to perform an enter or select function. It will be understood that other user input devices may be substituted for the keyboard  20 , main display  24 , side wheel  86  and other components of the computer system  10 . Similarly, other user input devices may be substituted for the keypad  34  and auxiliary display  30  in the removable module  28 .  
         [0025]     As shown in  FIG. 3 , the computer system  10  includes most of the usual connectors for connecting to external devices. More specifically, the computer system  10  includes a conventional universal serial bus (“USB”) port  90 , a DC power input jack  92 , and a docking connector port  94 . The various communication ports can be used to provide communication between an external device and the computer system  10 . Many such peripheral devices are well known, for example, printers, digital cameras, scanners, external disk drives, and the like. Although not shown in  FIG. 3 , the computer system also includes an Ethernet port, a modem port, a serial port, etc. In one embodiment, the rear portion of the computer system computer systemlo further includes an antenna window  98  for wireless communication. The computer system  10  can be equipped with wireless capability using IEEE 802.11 WiFi, Bluetooth, or other wireless communication protocols. The antenna  98  can be utilized for transmission as well as reception of wireless signals. The computer system  10  also includes an internal battery (not shown in  FIGS. 1-3 ) as well as in internal AC powered battery charger (not shown).  
         [0026]     The removable module  28  may be used to provide access to the applications corresponding to the icons  40 - 54  when either the lid  12  is closed and the computer system  10  is turned off or the module  28  is entirely removed from the computer system  10 . Also, the computer system  10  preferably may be placed in a quiescent low power mode. When the lid  12  is closed and the computer system  10  is in the low power mode, the removable module  28  may also be used to provide access to the applications corresponding to the icons  40 - 54  computer system. As explained in greater detail below with reference to  FIG. 4 , the applications corresponding to the icons  40 - 54  are executed by a processor in the removable module  28 . Therefore, the module  28  can be used to perform key tasks like checking emails, viewing contact and calendar information, recording voice memos, and playing music files when the computer system  10  is turned off or the module  28  is removed from the computer system  10 . The module  28  may thus be used like a PDA without the need to boot up the computer system  10  and load its operating system, and without the need to open the lid  12  of the computer system  10 . When the computer system  10  is turned on, and the removable module  28  is physically and electrically integrated with the computer system  10  as shown in  FIGS. 1 and 2 , a processor in the computer system chassis  14  can access the functionality provided by the removable module  28  through the keyboard  20  and the main display  24 . Additionally, the information provided by the module  28  is synchronized to the information stored in the computer system  10 . The computer system  10  may be configured to automatically transition from the power saving mode to an active normal operating mode when the module  28  is received by the chassis  14 .  
         [0027]     The hardware architecture of the computer system  10  and the removable module  28  will now be explained with reference to the block diagram of  FIG. 4 . However, it will be understood that other hardware configurations may alternatively be used. The hardware of the computer system  10  provides a suitable computing environment for the software architecture, including operating systems and applications. The chassis  14  of the computer system  10  includes a computer system processor  100  coupled to a processor bus  104 . The processor bus  104  preferably includes a command/status bus, an address bus and a data bus. Although the computer system processor  100  preferably includes a level 1 (“L1”) cache, the computer system  10  includes a level 2 (“L2”) cache  108 , which is coupled to the computer system processor  100  through the processor bus  104 . The L2 cache  108  includes the usual tag and data memories, which are normally implemented using static random access memory (“SRAM”) devices.  
         [0028]     The computer system processor  100  accesses a number of computer components through a system controller  120 , which is also connected to the processor bus  104 . The system controller  120  includes a memory controller  124  that is coupled through a memory bus  126  to a system memory  128 . The memory bus  126  includes a command bus through which memory commands are passed to the system memory  128 , an address bus specifying a location in memory that is being accessed by a read or write command, and a bi-directional data bus through which write data are passed to the system memory  128  and read data are passed from the system memory  128 . A suitable random access memory device, typically a dynamic random access memory (“DRAM”) device, is used as the system memory  128 .  
         [0029]     The system controller  120  also includes a graphics port that is coupled to a graphics processor  130 . The graphics processor  130  is, in turn, coupled to the main display  24 , which may be a liquid crystal display (“LCD”), but may also be an organic light emitting diode (“OLED”) display, a plasma display, a field emission display (“FED”), or some other type of display.  
         [0030]     The system controller  120  also serves as a bus bridge between the processor bus  104  and a peripheral bus  140 , which may be a peripheral component interconnect (“PCI”) bus. The peripheral bus  140  is coupled to a FAX/modem  142  and a disk drive  144  accessing a hard disk  146 , which together provide non-volatile storage of computer readable instructions, program modules, data structures, and other data. However, other types of non-volatile storage may also be used, such as flash memory cards, recordable CD-ROM and DVD disks, Bernoulli cartridges, smart cards, to name a few. The peripheral bus  140  is also coupled to a network interface  154  that is used to provide communications through a suitable local area network (“LAN”), such as an Ethernet network. The network interface  154  may also provide access to a wireless network, such as 802.11 WiFi, Bluetooth, cellular using TDMA, FDMA and/or CDMA radios, or some other wireless communication links. As part of the user interface for the computer system  10 , the peripheral bus  140  is also coupled to a pointing device  156 , such as an external mouse and the touchpad  22 , and a keyboard interface  158 , which is coupled to the keyboard  20 . The peripheral bus  140  is coupled to a read only memory (“ROM”) device  160 , which stores a basic input/output system (“BIOS”) program that includes a boot sequence, which is executed by the high power processor  100  at power-up. The BIOS program stored in the ROM device  160  will be described in greater detail with reference to  FIG. 5 . The BIOS program is preferably shadowed by being transferred from the ROM device  160  to the system memory  128  as part of the boot sequence, and it is then executed by the high power processor  100  from the system memory  128 .  
         [0031]     The peripheral bus  140  is also coupled to an audio interface  162  that is connected to an internal microphone  164  and a pair of speakers  166   a,b . The audio interface  162  includes a digital-to-analog converter having a pair of outputs that are coupled to the speakers  166   a,b . The audio interface  162  also includes a sampler producing analog samples of a signal from the microphone  164 , and an analog-to-digital converter, which digitizes the analog samples and passes the digital sample data to the peripheral bus  140 .  
         [0032]     The processor bus  104  in the chassis  14  of the computer system  10  is connected to a processor bus  168  in the removable module. Also connected to the processor bus  168  is a module processor  170 . The module processor  170  is used to support the functionality that is available using the removable module  28 . The processor  170  is coupled through the processor bus  168  to a module system controller  180 , which also includes a memory controller  184 . The memory controller  184  is coupled to a system memory  186 , which may be a DRAM device, through a memory bus  188 . The system memory  186  may have a capacity that is smaller than the capacity of the system memory  128 , and it may operate at a substantially slower speed. The system memory  186  is accessed by the module processor  170 , although in some embodiments it may also be accessed by the computer system processor  100 . The system controller  184  is coupled to a peripheral bus  190 , which may be a PCI bus, and an ISA bus or some other type of bus. The system controller  184  and the peripheral bus  190  couple the module processor  170  to the side wheel  86 , a display interface  194  for the touch-screen display  30 , and a keypad interface  196 , which is coupled to the membrane keypad  34 . In an embodiment, the peripheral bus  190  is also coupled to a ROM  198  that stores a BIOS program and operating system for the module processor  170 . The ROM  198  may also store firmware for the applications used by the removable module  28  in its stand-alone mode. These applications are run on the module processor  170 , which, in conjunction with the system controller  180 , system memory  186  and components coupled to the peripheral bus  190 , are used to support the functionality of the removable module  28 . A miniature disk drive  200  is also coupled to the peripheral bus  190  for accessing a hard disk  206 , which provides non-volatile storage of at least the data that is used by the removable module  28  in its stand-alone mode. Such data would include, for example, email messages, a contacts list, an appointment calendar, an MP3 or other audio files. The hard disk  206  may also store computer readable instructions, program modules, data structures, and other data if they are not stored in the ROM  198 . Although a disk drive  200  and hard disk  206  are used as the high capacity, non-volatile storage means in the embodiment shown in  FIG. 4 , it will be understood that other types of non-volatile storage may also be used.  
         [0033]     Although the chassis  14  of the computer system  10  is shown in  FIG. 4  as being coupled to the removable module  28  through interconnected processor buses  104 ,  168 , it will be understood that they may be coupled to each other by other means. For example, the processor buses  104 ,  168  may be isolated from each other, and the chassis  14  and removable module  28  may be coupled to each other through a communications link (not shown).  
         [0034]     The computer system  10  also includes an AC to DC converter  210  that generates a DC voltage for supplying power to the electrical components in the computer system and for charging a battery  214  in the chassis  14  of the computer system  10 . When the converter  210  is not connected to a source of AC power, the battery  214  supplies power to the electrical components in the computer system  10 . DC power from either the converter  210  or the battery  214  is also applied to a battery charger  216  that generates a controlled DC voltage for charging a battery  218  in the removable module  28 . When the computer system  10  is coupled to a source of AC power, the converter  210  supplies power to the battery charger  216 , which, in turn, supplies power to the removable module  28 . When the removable module  28  is present in the chassis  14  of the computer system  10 , the module  28  receives power from the battery  218 . When the computer system  10  is not connected to a source of AC power but the module  28  has not been removed from the chassis  14 , the module  28  can receive power from either the battery  218  or the battery  214  in the chassis  14  through the battery charger  216 .  
         [0035]     In operation, the computer system processor  100  boots up from the system memory  128  after the boot sequence and the operating system have been transferred to the memory  128 . The module processor  170  boots up by executing a BIOS program stored in the system memory  186  after the BIOS program stored in the ROM  198  has been shadowed to the memory  186 . The operating system for the module processor  170  is also transferred from the ROM  198  to the system memory  186 . However, the BIOS program and the operating system for the module processor  170  may be transferred to the system memory  186  by other means. For example, the BIOS program and operating system may be stored in the hard disk  146  and transferred to the system memory  186  by the high power processor  100 . Once the operating systems have been loaded into the system memories  128 ,  186 , the computer system  10 , including the removable module  28 , are operational.  
         [0036]     When the computer system  10  has been turned off, power is removed from the electrical components in the chassis  14  of the computer system  10 . However, in some embodiments, power may still be applied to at least some components of the removable module  28 , including the module processor  170  and the system memory  186 , so the module  28  can provide virtually instant access to the features of the removable module  28 . The user interface to these features is then provided by the touch-screen display  30 , the keypad  34 , and the side wheel  86 . However, in some embodiments, the module processor  170  has the ability to “wake-up” or re-power the computer system processor  100  to access components in the computer system  10 .  
         [0037]     Although the relatively low performance of the processor  170  and the relatively small capacity and slow speed of the system memory  186  do not provide nearly the processing capabilities of the computer system processor  100  and system memory  128 , they provide adequate processing capability to perform the functions accessed through the removable module  28 . As explained above, these functions include email, access to a contacts listing, access to an appointment calendar, and playing audio tracks. Moreover, these functions can be easily accessed since it is not necessary to open the lid  12  ( FIGS. 1-3 ) or to wait for a boot sequence to run and the operating system to be loaded.  
         [0038]      FIG. 5  is a plan view of another embodiment of a removable module  230  that may be received by the chassis  14  of the computer system  10  in place of the removable module  28  shown in  FIGS. 1-3 . The removable module  230  includes a touch-screen display  234 , a speaker  236  and a microphone  238 . Inside the removable module  230  are conventional cellular telephone components  240  powered by the battery  218 . The removable module  230  also includes a video camera  246  of conventional design. Coupled to the video camera  240  are conventional video circuitry  248 , such as a video signal sampler, which produces analog samples of the video signal from the camera  246 , and an analog-to-digital converter for digitizing the samples and passing them to a peripheral bus. The module  230  also includes a fingerprint reader  250  coupled to a conventional fingerprint interface unit  254 . A global positioning system (“GPS”) sensor  260  is included in the module  230  for providing position information. Finally, the removable module  230  also includes a TV tuner  262  for receiving broadcast television signals. The touch-screen display  234  is also used with the above components. Specifically, in addition to displaying hot keys for use with the cellular telephone components, the display  234  can be used for such purposes as to view video frames being captured by the video camera  246 , to view television programming received by the TV tuner  262 , and to view position or other related information provided by the GPS sensor  260 . The touch-screen display  234  can also display hot keys that can be pressed to control and configure the video camera  240 , the fingerprint reader  250 , the GPS sensor  260 , and the TV tuner  262 .  
         [0039]     The removable module  230  provides the computer system  10  with significant functionality when it is received by the chassis  14  of the computer system. For example, the cellular telephone components provide the computer system  10  with wireless email and browsing capabilities through a dialup Internet Service Provider or Bluetooth link. The video camera  240  allows the computer system to act as a Web cam for a variety of applications, including video conferencing. Additionally, video and digital photographs obtained using the video camera  240  can be stored in the computer system  10  and later viewed or edited with conventional video and photograph editing applications. The fingerprint reader  250  is used by an application in computer system to disable it from operating unless a fingerprint read by the reader  250  matches a fingerprint profile stored in the chassis  14  of the computer system  10  and/or the removable module  230 . The fingerprint reader  250  can also be used to provide authentication of transactions made using the Internet, such as the purchase of goods or services or accessing confidential banking or other records. The GPS sensor  260  can be used by a mapping application to show the position of a user on a map shown on the main display  24 . The TV tuner  262  can be used to record TV programming for subsequent viewing. The above are illustrative examples of how the features in the removable module  230  can be used. It will be understood that they can also be used for other functions.  
         [0040]     The removable module  230  also has substantial functionality as a stand-alone unit when it is removed from the chassis  14  of the computer system. The module  230  can be used as a conventional cellular telephone for voice communications or with the video camera  240  to provide images during a telephone conversation. The video camera  240  can also be used as a video recorder or as a digital camera. The fingerprint reader  250  can be used to disable the module  230  from operating unless a valid fingerprint has been read by the reader  250 . The GPS sensor  260  can be used to provide position information for use by emergency personnel responding to a “911” call so the location of the individual requesting assistance can be easily determined. The TV tuner  262  can be used to view television broadcasts in the display screen  234 .  
         [0041]     Other embodiments of removable modules for use in the computer system can combine different combinations of the features present in the removable module  28  of  FIGS. 1-4  and the removable module  230  of  FIG. 5 , as well as features developed in the future. By combining desired features in a removable module, the computer system can be provided with the capabilities provided by the module, and the features can be easily used by the module as a stand-alone unit.  
         [0042]     Although the present invention has been described with reference to the disclosed embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. Such modifications are well within the skill of those ordinarily skilled in the art. Accordingly, the invention is not limited except as by the appended claims.