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Description  |
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FIELD OF THE INVENTION
This invention relates to computer systems which automatically configure
their I/O (input/output) attachments when power is turned on.
BACKGROUND OF THE INVENTION
In existing computer systems, I/O adapters have stored identifier (ID)
functions which are detected by the system during its initialization
process, and enable the system to determine if its I/O configuration has
changed since power was last turned off. If the configuration has not
changed, the initialization process automatically conditions the adapters
to operating states suited to the existing configuration. Thus, it is not
necessary for the system to repeat any "setup" procedures associated with
establishing the operating states of this configuration.
When an I/O adapter card is first installed into an attachment slot of the
system, which previously was either vacant or connected to a different
adapter, a setup process is initiated by the system which requires
interaction between the system and a user. In this process, configuration
state information relating to the newly installed adapter card is created
by the system and stored in a non-volatile system memory (NVRAM) along
with a copy of the adapter's ID function. Each time that power is turned
on the system executes a power on self test (POST) procedure in which it
determines (among other things) if ID's associated with the slots are the
same as they were when power was last turned off. If the ID's haven't
changed, the system causes associated configuration information to be
transferred from NVRAM to volatile registers in respective adapter cards,
thereby conditioning the adapter cards to operating states suited to the
current configuration of the system. If the ID's have changed, another
setup process is initiated.
For details of the foregoing, refer to U. S. Pat. No. 5,038,320 to Heath et
al, assigned to the assignee of the present application.
The setup procedure can be time consuming, inasmuch as it may require the
system user to deactivate and reboot the system several times, but it
generally does not overly delay productive use of the system since adapter
installation changes usually are made infrequently.
However, in some systems, frequent changes of adapter configurations may be
necessary for practical operation of the system. For example, a notebook
computer system may be used at some times as a stand-alone portable
computer and at other times as part of a desktop system. In the desktop
configuration, the computer may be connected to an expansion unit which
provide additional functions such as communication, printing, extra
memory/storage, etc.
In such frequently changing environments it is desirable to be able to
avoid having to repeat setup processes to recreate configuration state
information that the system has previously created. The present invention
provides such capability.
OBJECTS OF THE INVENTION
An object of the invention is to provide a mechanism and associated method
for enabling a computer system to avoid having to repeat previously
executed setup procedures when its configuration of attachments is changed
to a configuration that had existed earlier.
Another object is to provide a mechanism and method for enabling a computer
system to automatically and efficiently initialize devices, that have just
been attached to the system in a connection configuration which existed at
some previous time, without user interaction and in a time which is much
shorter than the time that would be required to accomplish the
initialization via a setup process involving user interaction.
SUMMARY OF THE INVENTION
These objects are realized by storing a backup copy of configuration state
information, relative to each configuration initially established by
execution of an otherwise conventional setup procedure (conventional
except for storage of the backup copy). The backup copy is stored in a
secondary storage device, in association with adapter identifier's (ID's)
which identify the devices currently connected to the system, in a form in
which the information is always accessible to be automatically retrieved
and re-used by the system without user action.
When a device adapter is first attached to the system, a user/installer is
guided interactively through a conventional setup procedure by which
system configuration state information associated with the configuration
formed by attachment of that adapter is created and stored in a system
NVRAM. However, in accordance with the present invention and as an
extension of the setup procedure, a backup copy of the same information is
stored in an automatically retrievable form, in a secondary non-volatile
store present in the system; e.g. a hard disk drive (HDD) storage device.
The backup copy is stored in association with identifiers (ID's)
corresponding to the currently attached adapters, and is thereby
automatically retrievable in association with the current attachment
configuration, whenever that configuration is re-established.
At each start-up, the system POST (power on self test) process detects ID's
of adapters which are currently attached to the system, and determines if
they correspond to ID's currently stored in system NVRAM (i.e. it
determines if the current I/O configuration is the same as that which
existed when system power was last turned off). If the ID's correspond,
POST transfers configuration state information from its NVRAM to the
adapters as before, establishing the adapters in operating states suited
to the current configuration.
However, if any ID does not correspond, the system does not immediately
call for setup action. Instead, POST attempts to locate a backup copy of
configuring information associated with the currently detected
configuration of adapter ID's. If a backup copy is not located, setup
action is evoked. But if a corresponding backup copy is found, POST
retrieves it automatically (without user interaction), transfers a copy of
it to NVRAM and uses the transferred information to set the currently
attached adapters into states suited to their aggregate configuration.
The portion of the secondary storage device used for storing backup
configuration information is either exclusively reserved for that function
(i.e. for exclusive use only by the POST process) or otherwise protected
against being overwritten during normal operation of the system.
It should be understood that when the HDD or other secondary storage device
is first installed in the system, the system may be operated to create
configuration information relative to a variety of different devices,
which may or may not be eventually attached, and to store backup copies of
that information in the secondary storage device; provided of course that
the storage device has sufficient capacity to allow for such usage. It
should also be understood that if the NVRAM memory has sufficient capacity
it may be used to store both the principal copies and backup copies of the
configuration information.
These and other features, effects, advantages and benefits associated with
the present invention may be more fully understood and appreciated by
considering the following description and claims.
DESCRIPTION OF THE DRAWINGS
FIGS. 1A and FIG. 1B collectively show a block diagram of a computer system
embodying the invention.
FIG. 2 illustrates storage of backup copies of information, in the hard
disk drive unit of the embodiment in FIG. 1, that is useful by the system
of that embodiment for configuring device adapters currently attached to
I/O slots thereof.
FIG. 3 is a flowchart showing the setup procedure in accordance with the
invention relative to the embodiment of FIG. 1.
FIG. 4 is a flowchart showing a power on self test (POST) procedure for
initializing the system embodiment of FIG. 1 in accordance with the
invention.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1A and 1B collectively show an embodiment of a data processing system
containing a computer system unit 1 constructed according to the present
invention. Unit 1 contains a system bus 3 connected with multiple
sockets/slots, #1, #2 and #3, into which I/O attachment cards may be
inserted. Such cards may be used to control various different types of
peripheral device apparatus (e.g. disk drive, printer, communication
device, extended memory device, etc.) and are interchangeably insertable
into any of the sockets. Also connected to bus 3 are a ROM (read only
memory) 5, for storing its POST and BIOS (basic input output system)
programs, a NVRAM (non-volatile RAM) memory 7 for storing configuration
information, a non-volatile secondary storage device HDD (hard disk drive)
9, a main memory 11, and a CPU (central processing unit) 13. The foregoing
elements may all be commonly housed as integral parts of unit 1.
To create configuration information, a setup program is used. The setup
program is contained in a utility program. The utility program is
contained either on a reference diskette supplied to the user with unit 1,
which operates through a not-shown diskette drive included in the unit, or
it may be contained on HDD 9.
As shown in FIG. 1, slots #1 and #2 in the system unit have attached
thereto respective adapter cards #A1 and #A2, and slot #3 in the system
unit has attached to it either expansion unit #E1 or expansion unit #E2
when the system unit is used in its desktop configuration. Each expansion
unit has multiple slots #4, #5 and #6 for attachment of additional adapter
cards; respectively for attachment of cards #X1, #X2, and #X3 to expansion
unit #E1, and cards #Y1, #Y2 and #Y3 to expansion unit #E2.
Each adapter card and expansion unit has a unique identifier (ID) value for
identifying its respective type of apparatus. Each ID consists of a
predetermined number of bits which are permanently stored on the
respective card in respective non-volatile storing means 21. Each card
also contains a (volatile) register 23 which can store associated
configuration state information when system power is on. Such
configuration state information can be stored in non-volatile form in
NVRAM 7, and transferred to the registers 23 of attached cards by POST if
the configuration of the system has not changed since it was last
deactivated.
The configuration state information includes, for example, address factors
(AD) assigning portions of system (memory and/or I/O) address space to the
respective card, interrupt priority level for interrupt requests presented
to the system unit by the respective card, information allocating
different priorities (PR) to cards of the same type, and/or information
ENBL for enabling and disabling cards of the same type which are
redundantly configured in the system. Based on this information, data is
efficiently transferrable between CPU 13 and the cards, and between cards.
In addition to means 21 for storing their ID values, expansion units #E1
and #E2 each have NVRAM's 25 for storing associated configuration
information. Such information is written from system unit 1 to respective
NVRAM's 25 during execution of the setup program after connection of
respective expansion units to the system. Each NVRAM 25 contains ID values
of all adapter cards currently attached to the I/O sockets/slots on the
respective expansion unit. Each NVRAM 25 also contains "name" information
uniquely identifying the respective expansion unit; for example EXP-1 for
unit #E1 and EXP-2 for unit #E2. Such names are required even if the units
and their respective attachments are identical, in order to allow the
system unit 1 to be able to distinguish between the expansion units (e.g.
to be able to create and write different configuration information to
those units; one possible use of which could be to configure one unit as
active and the other as standby in a redundant arrangement).
NVRAM 7 contains system configuration information for the last active
configuration of unit connections in the system; i.e. the configuration
established at the last initialization of the system. Such information
includes identifier and configuration state information, for each adapter
card and expansion unit connected in the system slots in the associated
configuration. Whenever a new configuration of unit attachments is formed,
corresponding system configuration information is created by the setup
program and stored in NVRAM 7. NVRAM 7 is continuously powered by system
power and/or a not-shown back-up battery. In the collective illustrations
of FIGS. 1A and 1B NVRAM 7 is shown holding a particular set of system
configuration information designated "system configuration information #1
". For purposes of the following discussion, it is assumed that system
configuration information #1 is associated with a configuration in which
slot #3 is empty, and slots #1 and #2 respectively have adapter cards #A1
and #A2 connected to them.
FIGS. 1A and 1B collectively show that hard disk drive (HDD) 9 contains a
special reserved area used for storing "backup" copies of system
configuration information in accordance with the invention. This area is
reserved exclusively for storing such information (meaning that it can not
be available to the operating system or application programs of system
unit 1 for storing any other information). The reserved area of HDD 9 can
be used to store plural sets of different system configuration
information; one set corresponding to the latest configuration #1, and
others corresponding to other system configurations (#2, #3, etc.)
previously formed and set up. For example, system configuration
information #2 could be associated with connection of adapter cards #1 and
#2 to slots #1 and #2 respectively, and connection of expansion unit #E1
to slot #3, and system configuration information #3 could be associated
with connection of adapter cards #1 and #2 to system slots #1 and #2
respectively and connection of expansion unit #E2 to slot #3.
Viewing system unit #1 as a contemporary laptop or notebook type system,
system configuration information #1 would be associated with standalone
operation of the system with only cards #1 and #2 internally installed,
system configuration information #2 and #3 would be associated with
operation of the system unit docked (attached) to expansion unit #E1 via
system slot #3, with cards #1 and #2 respectively attached to system slots
#1 and #2 and cards #X1, #X2 and #X3 attached to respective slots in unit
#E2, and system configuration information #3 would be associated with
operation of the system docked to expansion unit #3, with cards #1 and #2
attached to the system slots as before and cards #X1, #X2, and #X3
attached to respective slots in unit #E3.
FIG. 2 shows an arrangement in accordance with the invention for locating
backup copies of sets of system configuration information within the
reserved area of HDD 9. Each time the system set up program is run
relative to a new system configuration #j (j=1,2, . . . ), the (setup)
program creates associated system configuration information #j which is
stored in NVRAM 7. As noted previously. this information includes card
and/or expansion unit identifiers, and configuration state information for
respective units. This information is also stored in the reserved area of
HDD 9, with the unit identifiers located in an index #j and the state
information located in a space indicated by a pointer value in the
respective index #. Index values for all established sets of system
configuration information are stored in successive positions within a
first part of the reserved area, as shown in FIG. 2, and associated sets
of configuration state information are stored in another part of the
reserved area, the location of each being indicated by the pointer in the
respective index. Thus, each set of system configuration information #j is
retrievable by reference to the associated index #j which in turn is
locatable by association with respective unit identifiers (card ID and
expansion unit names associated with the respective configuration).
Each index value also contains status information which indicates the type
of identifying information contained in that index (e.g. card ID's only,
expansion unit name only, or both), to facilitate efficient scanning of
the indexes by POST when retrieval of a backup copy of state information
is required.
FIG. 3 shows a procedure for creating and storing system configuration
information in accordance with the invention. The information is created
in step 1, with reference to card ID's and expansion unit names detected
by interrogating the system unit slots, and written to NVRAM 7 in step 2.
Steps 1 and 2 corresponds to the prior art setup procedure used in
contemporary computer systems. In step 3 a backup copy of the same system
configuration information is written to the reserved area of HDD 9 in a
form suitable for retrieval; e.g. in the form shown in FIG. 2 with
associated index information. If the configuration does not include an
expansion unit, the procedure ends after step 3. However if the
configuration includes an expansion unit, configuration identifying
information associated with that unit (unit name and ID's of adapter cards
attached to the unit's slots) is written to NVRAM on the expansion unit
(NVRAM 25 in FIGS. 1A and 1B), in step 4, to complete the process.
FIG. 4 shows how backup system configuration information of the invention
is used by system POST (power on self test) for system initialization.
Actions involved in this process are designated steps 11 through 19. Steps
11 through 13 and 16 correspond to POST actions performed in prior art
systems.
In step 11 diagnostic tests are performed on all constituent pads of the
system (the system unit itself and its attachments if applicable). In step
12 configuration identifying information is retrieved relative to the
system unit I/O slots (and other system ports or elements if applicable).
Relative to I/O slots currently connected to adapter cards, the
identifying information consists of the respective card ID values, and
relative to slots which are empty the identifying information consists of
an ID value representing an empty state. In step 13 the identifying
information for each system slot is compared to identifying information in
system NVRAM 7 associated with the previous state of the respective slot
(the state when system unit power was last turned off).
If all comparisons in step 13 are in accord (all ID's retrieved in step 12
agree with respective ID's previously retained in system NVRAM), the
process advances directly to step 14, but if any compared ID's disagree
the process branches to step 17 for attempting retrieval of backup system
configuration information in accordance with the present invention.
In step 14, system configuration information is copied from system NVRAM to
registers 23 on any adapter cards that are directly attached to system
unit slots. If an expansion unit is currently connected to a system unit
slot, step 15 is performed to copy the configuration information relevant
to that expansion unit from system NVRAM to the NVRAM on the expansion
unit. If no expansion unit is attached, the process ends after step 14,
but if an expansion unit is attached step 14 is followed by steps 15 and
16. Step 15 transfers configuration information from NVRAM 7 to the NVRAM
in the expansion unit. Step 16 checks that the actual card configuration
of the expansion unit matches the information transferred to its NVRAM.
If ID's compared in step 13 disagree, an attempt is made in step 17 to
retrieve system configuration information from the reserved area of HDD 9.
The action next taken depends upon whether or not the attempt is
successful. In step 17, POST compares the configuration identifying
information detected in step 12 (ID's of currently attached adapter cards
and name of currently attached expansion unit if one is attached) to
identifiers in successive indexes in the HDD reserved area to find a
matching set of identifiers if an index containing such a set exists.
If an associated index is found, its pointer is used to retrieve the
associated system configuration information (see FIG. 2). If the
configuration information is successfully retrieved, the process advances
to step 18 where the retrieved information is written to the system unit
NVRAM, and relevant portions of that information are transferred to
registers 23 on the cards and NVRAM on an expansion unit if one is
attached (steps 14-16 discussed previously).
If an associated index is not found, or associated system configuration
information is not otherwise retrievable, the attempt in step 17 is
unsuccessful and the process branches to step 19 to evoke a setup process
for the current "new" system configuration. As noted earlier this process
may be time consuming, in that it may require system user participation
and several rebootings of the system. After successful completion of the
setup process, the system is rebooted and the POST process of FIG. 4 is
then repeated with a successful retrieval of system configuration
information from the HDD, etc.
It should be appreciated that once system configuration is saved to the HDD
(or equivalent storage), it is unnecessary to repeat the setup process by
which that information is created. Therefore, in system usage environments
which are expected to have frequently alterable
configurations--exemplified by notebook type systems which are operated in
standalone and docked configurations--the invention allows for more
efficient operation of the system at each change of configuration.
Furthermore, in such environments, certain failures of attachments to
expansion units may be readily detectable since each expansion unit
contains a respective NVRAM to store ID's of adapter cards attached to it.
Detection of failure or error would result if an ID read from a card
attached to the expansion unit did not match the ID associatively held in
the NVRAM of that unit. But even if the ID read from a faulty card
happened to match that in the expansion unit NVRAM, the resulting state of
the expansion unit usually would be erroneous in respect to the active
state transferred to that card and the fault would be detectable by other
tests.
Furthermore, by assigning unique names to the expansion units, the
illustrated embodiment allows for the system to be able to differentiate
between identical expansion units having respectively identical card
attachments. Thus, for example if the system is connectable to a network
through two identical expansion units, each containing identical
communication adapter card attachments, the system would be able to assign
different communication addresses to the cards in each expansion unit for
allowing respective cards to perform different functions in the network.
Or if two identical expansion units contained identical type memory
extension adapter cards having different memory capacities, this
capability would enable the system to differentiate the expansion units
and thereby correctly use the amount of memory available in each expansion
unit.
Furthermore, the invention allows for automatic retrieval of system
configuration information relative to altered configurations of slots that
do not connect to expansion units. Thus, if a system is used in a mode in
which card connections to slots on either the system unit or an expansion
unit are subject to frequent change, the invention would enable the system
to avoid unnecessary repetition of setup procedures when card
installations are changed to form a pre-existing card configuration.
It also should be understood that although the secondary store for backup
copies of system configuration information is shown as a hard disk drive
in the described embodiment, it would be feasible to use other storage
devices--e.g. optical disk drive, floppy disk drive, EPROM, EEPROM,
battery backed up NVRAM, etc.--for the same function, so long as the
device used is always accessible at system startup and its stored
information is protected against unintentional alteration.
It also should be appreciated that with a large enough system NVRAM, a
separate HDD or other storage device would not be needed. With such
capability, system configuration information for all previously set up
configurations could be stored in the system NVRAM, in association with
slot/device ID's and expansion unit names, and selected directly by the
POST program for association with any current configuration.
It should be appreciated also that the invention could be useful even in
systems not having connectable expansion units, but otherwise subject to
dynamic changes of configuration.
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