Patent Grant
7062627
1. Field of the Invention
The present invention relates to an information processing apparatus capable of having its main memory expanded while operating.
2. Description of the Related Art
Heretofore, to expand a memory of a system has required three steps: the system is stopped, an additional memory is installed, and the system is restarted. Such techniques are disclosed illustratively in a PC instruction manual, “Hitachi Personal Computer FLORA 1010DI/DM: Your First PC (manual on hardware),” pp. 107–110 (a Japanese publication; Cited Reference 1). This publication describes the need for expanding a memory of a personal computer with its power cable disconnected. Techniques for connecting a device to a system in operation are disclosed in “The Winn L. Rosch Hardware Bible” by Rosch, Winn L, pp. 347–356, published by Samsung America Incorporated (Cited Reference 2). The Cited Reference 2 discusses PCMCIA specifications for allowing memories to be installed or removed while power is being applied. Other techniques for connecting a device to a system in operation are disclosed in the Jun. 2, 1997 issue of Nikkei Electronics (a Japanese publication), pp. 109–112 (Cited Reference 3). Discussed in the Cited Reference 3 are PCI bus specifications for allowing components to be attached or detached during power application.
Because it has been necessary to stop power to the system when a memory is being added thereto, the expansion of memory resources has conventionally required executing two related processes: stopping the system, and initializing the system. In the case of the operating system (OS) generally used in a workstation/server environment, it has typically taken 30 to 60 minutes to stop and initialize the system, including the steps of stopping and initializing application software.
One way of adding a memory during system operation is by having recourse to a cluster system. The cluster system is constituted by a plurality of information processing apparatuses each performing a specific service. In this system, while one apparatus is being stopped, others function to provide their services continuously. One obvious disadvantage of this system is the need for preparing a plurality of information processing apparatuses.
It is therefore a first object of the present invention to provide a memory managing method for allowing a memory to be added to an information processing apparatus in operation without preparing a plurality of information processing apparatuses.
It is a second object of the invention to provide a memory managing method for reserving a management region of a first memory connected to a processor so that the processor may use an added second memory.
It is a third object of the invention to provide a memory managing method whereby the difference between a predetermined memory size and a currently installed memory size is established as an additional memory size.
In carrying out the invention and according to one aspect thereof, there is provided a memory managing method for use with an information processing apparatus comprising a first memory and a processor for processing information held in the first memory, the information processing apparatus further allowing a second memory to be added thereto while being powered, the memory managing method comprising the steps of: connecting the processor to at least one of the first and the second memories; storing sizes of the first and the second memories connected to the processor; and storing information about whether or not each of the first and the second memories is connected to the processor.
According to another aspect of the invention, there is provided a memory managing method for adding a second memory to an information processing apparatus comprising a first memory, the memory managing method comprising the steps of: establishing a total memory size for the information processing apparatus; calculating a size of an actually installed memory of the information processing apparatus when the information processing apparatus is started; allocating in the first memory a memory management region based on the total memory size; establishing management information about the actually installed memory; calculating as an expandable memory size a difference between the total memory size and the size of the actually installed memory when the second memory is added while the information processing apparatus is operating; and establishing memory management information about the expandable memory size in the first memory.
According to a further aspect of the invention, there is provided an information processing apparatus for allowing a memory to be added thereto while being powered, the information processing apparatus comprising: a first memory; a processor for processing information held in the first memory; and establishing means for establishing a total memory size for the information processing apparatus; wherein the processor calculates a size of an actually installed memory of the information processing apparatus when the information processing apparatus is started; wherein the processor allocates in the first memory a memory management region based on the total memory size; wherein the processor establishes memory management information about the actually installed memory in the first memory; wherein the processor calculates as an expandable memory size a difference between the total memory size and the size of the actually installed memory when the second memory is added while the information processing apparatus is operating; and wherein the processor establishes memory management information about the expandable memory size in the first memory.
The above features of the invention allow a memory to be added to an information processing apparatus while the latter is operating.
Other features, objects and advantages of the invention will become more apparent upon a reading of the following description and appended drawings.
Preferred embodiments of this invention will now be described with reference to the accompanying drawings.
The processor 10 is illustratively a CPU. The main memory 20 and the added main memory 60 are illustratively a RAM each. Made of TTL or CMOS logic circuits, the connecting switch 50 is a facility that connects the processor 10, main memory 20 and added main memory 60. The connecting switch 50 includes connection managing means 40 for managing logical connection status. Specifically, the connection managing means 40 manages the presence and absence of logical connections, i.e., the availability of signal exchanges, between the processor 10 and the connecting switch 50, between the main memory 20 and the connecting switch 50, and between the added main memory 60 and the connecting switch 50.
Management information 41 is used to manage the connection status of each of configured ports of the connecting switch 50. In the example of
The connection managing means 40 is illustratively made up of TTL or CMOS logical circuits. The management information 41 may be held in a RAM.
In the above computer, no signals are transmitted to the parts that are not logically connected. In other words, if logically disconnected parts are physically connected, no noise is transferred therebetween; no signal exchange occurs between two physically connected parts unless they are logically connected. Upon power-up, physical and logical connections are established between the processor 10 and the connecting switch 50 as well as between the main memory 20 and the connecting switch 50, while the added main memory 60 is physically disconnected from the connecting means 50. The connecting switch 50 may be connected physically during operation but not logically. The added main memory 60 is first connected physically to the connecting switch 50 and, upon elapse of a predetermined period of time in which connection-triggered noise is allowed to disappear, the connection managing means 40 is updated to establish a logical connection between the memory 60 and the connecting means 50. This procedure permits a memory expansion for the computer during operation.
Addition reporting means 30 for reporting an addition of parts to the computer may be implemented using a switch corresponding to each added part. In the example of
The addition reporting means 30 may be implemented by use of an input/output device comprising a program running on the processor 10, a keyboard, and a display unit. Illustratively, a character string may be input from the keyboard to alter that management information 41 in the connection managing means 40 which corresponds to the processor 10. The addition reporting means 30 thus practiced is as effective as the theoretical setup discussed above. Although the addition reporting means 30 is incorporated in the connecting switch 50 in the example of
In the example of
Below is a description of the processing that takes place when a memory is added to the information processing apparatus in operation. The added main memory 60 shown in
The processor 10 then initializes the added main memory 60 and checks an available memory size. Finally, the processor 10 raises the available end address 23 in the main memory management information 21 (shown in
An added main memory 60 is not connected upon power-up; the memory 60 is connected to the bus 80 after the system has started operating.
In the above setup, connecting the added main memory 60 to the bus 80 can trigger electrical noise on the bus 80; the noise needs to be averted using bus controlling means 70. The processor 10, main memory 20 and added main memory 60 are identical to those shown in
Below is a description of the processing that takes place when a memory is added to the computer of
Thereafter, the processor 10 initializes the added main memory 60 and checks an available memory size. Finally, the processor 10 extends an available end address 23 in main memory management information 21 by an amount reflecting the additionally installed memory. This allows the processor 10 to start accessing the added main memory 60.
In some configurations, the computer 100 may include two or more I/O devices 130.
The processor 110 is illustratively a CPU. The nonvolatile memory 120 is a memory such as a ROM or a battery-powered RAM that retains its contents when a main power supply remains inactive. The ROM is preferably an EEPROM (Electrically Erasable Programmable Read Only Memory). The nonvolatile memory 120 comprises firmware 121 and configuration information 122.
The firmware 121 is made of a program for carrying out system initialization and basic input/output control. The configuration information 122 describes the current system configuration and is referenced by means of the firmware 121. The configuration information 122 includes real memory size information 123 indicating a currently installed memory size and expandable memory information 124 specifying an expandable memory information. The configuration information 122 is established through a setting menu of the firmware 121 and by a utility 142. Before the configuration information 122 is set or modified, restrictions associated with an operating system (OS) 141 in place should preferably be checked. The utility 142 is provided as an ordinary program.
The I/O device 130 is used to carry out input and output operations. Illustratively, a keyboard, a display unit, a printer and a network may constitute the I/O device 130.
The secondary storage device 140 retains its contents while the main power supply is being turned off. Illustratively, the storage device 140 may be a hard disk drive, an optical device such as a CD-ROM drive, a magneto-optical disk drive such as an MO drive, or a magnetic tape device. The secondary storage device 140 accommodates the Os 141, utility 142 and data 143.
The memory 200 comprises a memory bus interface 210 and a storage facility 220. Illustratively made of TTL or CMOS logic circuits, the memory bus interface 210 allows contents of the storage facility 220 to be input and output via the bus. The memory bus interface 210 also has a hot-line insertion and removal function that may be implemented illustratively by use of the PCMCIA techniques mentioned in connection with the related art.
The storage facility 220 is illustratively a RAM. A first storage facility 220-1 for the first memory 200-1 includes an OS region 240 used by the operating system and a user region 230 for use by a user program. The OS region 240 has resource management information 250 which in turn includes main memory management information 21. The second memory 200-2 comprises a second storage facility 220-2 and a user region 230-2 used by a user program. The bus controlling means 70 and addition reporting means 30 are identical to those shown in
An initializing process of the computer will now be described with reference to
For normal operation, programs are generally run in the user region 230. The OS region 240 is allocated in the memory 200 that was connected upon power-up. In starting a program, the OS 141 generally references the main memory management information 21 included in the resource management information 250 so as to verify an available memory region. If the memory size required for start-up of the program is found to be greater than the currently available memory size, the OS 141 cannot start the program.
A memory adding process of the computer will now be described with reference to
In step 415, the addition reporting means 30 is controlled to request the bus controlling means 70 to open the bus 150. In step 418, the bus controlling means 70 opens the bus 150 accordingly. At this stage, the components in the system may gain access to one another over the bus.
In step 420, the processor 110 starts the utility 142 which in turn activates the firmware 121. The firmware 121 initializes the newly added second memory 200-2 in step 430 on the basis of the expandable memory information 124 included in the configuration information 122.
The utility 142 may be started in a number of ways: it may be started by an interruption issued by a bus interface, not shown, of the second memory 200-2 to the processor 110 when the second memory 200-2 is connected to the bus 150. Alternatively, the utility 142 may be started by a patrol program activated automatically at constant intervals. The utility 142 may otherwise be started by a user who enters a command.
Thereafter, based on the added memory size, the processor 110 updates the real memory size information 123 within the OS region 240 in the first memory 200-1. The processor 110 then passes control from the firmware 121 back to the utility 142. In step 440, the utility 142 calls up the OS 141. In turn, the OS 141 causes the firmware 121 to acquire the real memory size information 123 and to update the main memory management information 21. This completes the memory adding process. In the above process where the processor 110 started the utility 142 which in turn called the firmware 121 (i.e., in step 420), the processor 110 should preferably create and leave records about any memory expansion that may have been made in the secondary storage device 140 or nonvolatile memory 120.
Because the information after addition of the memory is retained in the main memory management information 21 under OS management (step 440), the added memory can be utilized by a user program that is started upon completion of the memory adding process. The main memory management information 21 is structured illustratively as shown in
Described below with reference to
Described below in detail with reference to
It is necessary to reserve beforehand a region for the second storage facility 220-2 planned to be added. Because the reserved region must exist inside a storage facility in effect upon power-up, that region needs to be allocated in the first storage facility 220-1.
When such a region is reserved, the user region is reduced by an amount that would have been made available if the region had not been set aside. It is therefore desirable for the computer to present guidelines by which to determine the size of the region to be reserved. Below is a description of what the utility 142 does when a region is to be reserved.
A region reserving process performed by the utility 142 is described below with reference to
In step 520, the utility 142 determines a reservable upper limit based on a currently installed memory size and on the results obtained in step 510. A minimally required memory size is defined for each operating system in advance. To have the OS 141 function normally requires that the current memory size minus the memory size representing a page structure of the added memory be at least equal to the minimally required memory size. A comparison is made between two values: one value is an added memory size determined so that the currently installed memory size minus the memory size representing the page structure of the added memory may become the minimum memory size; the other value is the maximum expandable memory size of the system minus the currently installed memory size. Of the two values compared, the smaller value is regarded as a maximum value that may be set to the expandable memory information 124; value zero is taken as a minimum value that may be set to the expandable memory information 124. The page structure signifies a data region for page management. With this invention, the page structure is made up of the logical-physical address translation pairs 26 and free list 27 shown in
In step 530, the utility 142 allows the user to select a value within the range of sizes defined above, and establishes the selected value. The value thus established is preferably written as a file to the secondary storage device 140 so that the value may be referenced by the utility 142.
Finally in step 540, the utility 142 sets to the expandable memory information 124 the value determined in step 530.
It is preferred that users be offered information specifying recommended system configurations such as memory sizes and the number of processors, as well as recommended expandable memory sizes contingent on the objective of the system. For example, half of a maximum value that may be set to the expandable memory information 124 is offered as a recommended expandable memory size.
Initialization of a computer implementing virtual memory is described below. The basic flow of processing is the same as that described with reference to
How a memory is added to a computer implementing virtual memory is described below. The basic flow of processing is the same as that described with reference to
In practicing the second embodiment, the inventors considered a computer which has functions for detecting failures of the memory 200 and for closing a failed memory portion and which is booted if the normally operating memory size minus the failed memory portion is at least equal to a minimum memory size needed to boot the OS (as discussed with reference to
The problem above is circumvented by the second embodiment of this invention wherein, if the normally operating memory size in effect at the time of setting an expandable memory size is less than the normally operating memory size at the time of booting, the expandable memory size setting is invalidated. The computer is then booted with the expandable memory size set to zero.
The second embodiment will now be described in more detail.
The interface with the other portions of the computer concerns the expandable memory information 124. This means that these portions of the computer of the second embodiment are the same with those of the first embodiment.
In practicing the third embodiment, the inventors considered a computer which has functions for detecting failures of the memory 200 and for closing a failed memory portion and which is booted if the normally operating memory size minus the failed memory portion is at least equal to a minimum memory size needed to boot the OS (as discussed with reference to
The first problem is that because any size of a management region designated for the expandable memory is allocated unchecked, a shortage of the normally operating memory size can occur. The memory shortage can prevent the computer from getting booted. The second problem is this: if a memory failure occurs following the setting of the expandable memory size, the sum of the normally operating memory size and the expandable memory size (called the total memory size) will become smaller than the total memory size at the time of the memory size setting.
In resolving the two problems above, the third embodiment uses the utility 142 to calculate an expandable memory size at the time of booting. There are two requirements for the calculation: (1) the normally operating memory size minus the management region for the expandable memory should not be less than the minimally required memory size; and (2) the expandable memory size should be set with a maximum available size not greater than {total memory size−normally operating memory size}.
It is required that the normally operating memory size minus the management region for the expandable memory be at least as large as the minimally required memory size. That requirement is defined by three sizes: a minimally required memory size, a memory page size, and a management region size per page.
The third embodiment will now be described in more detail. Below is an example in which a total memory size of 8 gigabytes is needed. There are two conditions to be met when the normally operating memory size minus the management region for the expandable memory needs to be at least as large as the minimally required memory size. The first condition is that the memory adding function is allowed to be used only if the normally operating memory size at the time of booting is at least “x” pages (“x” is an integer and one page makes up 4 kilobytes). The second condition is that the expandable memory size must not exceed the normally operating memory size at the time of booting multiplied by a factor of “y” (“y” is a floating-point number). The two conditions may be described as the following two expressions:
Normally operating memory size≧“x” pages (Expression 1)
Expandable memory size≦“y” x normally operating memory size (Expression 2)
Unlike the region reserving process of
As with the second embodiment, the computer of the third embodiment is initialized in accordance with the initializing process of
{total memory size−normally operating memory size at the time of booting}/normally operating memory size at the time of booting≦maximum ratio
If the result of the check in step 820 is negative, step 850 is reached; if the result is affirmative, step 830 is reached. The total memory size is the value held in the total memory size information 126 shown in
{total memory size−normally operating memory size at the time of booting}/normally operating memory size at the time of booting≦4.0
Step 830 is reached only if both the normally operating memory size lower limit and the limit to the maximum ratio are met. In step 830, the firmware 121 sets {total memory size−normally operating memory size at the time of booting} to the expandable memory information 124, and terminates the expandable memory information setting process. If the normally operating memory size lower limit is not met, step 840 is reached. In step 840, the firmware 121 sets zero to the expandable memory information 124 before terminating the expandable memory information setting process. In other words, the firmware 121 inhibits memory expansion upon judging that the main memory management information 21 cannot be secured for the memory to be added. If the normally operating memory size lower limit is met but the limit to the maximum ratio is not satisfied, step 850 is reached. In step 850, the firmware 121 reduces the expandable memory size so that the limit to the maximum ratio will be satisfied. More specifically, the firmware 121 sets
{normally operating memory size at the time of booting×maximum ratio}
to the expandable memory information 124 and terminates the process. If the limit 128 to the maximum ratio between the expandable memory size and the normally operating memory size is set for 4.0 as described above, the firmware 121 sets a value four times the normally operating memory size to the expandable memory information 124.
The interface with the other portions of the computer concerns the expandable memory information 124. This means that these portions of the computer of the third embodiment are the same with those of the first embodiment.
Although the Expressions 1 and 2 were presented above as conditional expressions to be met in terms of the expandable memory size and the normally operating memory size, this is not limitative of the invention. This invention also applies when other conditional expressions are suitably employed.
While preferred embodiments of the invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2796 | Jan 1998 | JP | national |
| 10-369019 | Dec 1998 | JP | national |
This is a continuation application of U.S. Ser. No. 09/227,740, filed Jan. 8, 1999 now U.S. Pat. Ser. No. 6,684,312. This application is related to U.S. Ser. No. 10/062,503, filed Feb. 5, 2002.
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| Number | Date | Country | |
|---|---|---|---|
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 09227740 | Jan 1999 | US |
| Child | 10642644 | US |
