Electrical computers and digital data processing systems: input/ – Intrasystem connection – Bus access regulation
Reexamination Certificate
1998-07-17
2001-04-24
Ray, Gopal C. (Department: 2181)
Electrical computers and digital data processing systems: input/
Intrasystem connection
Bus access regulation
C710S001000, C710S008000
Reexamination Certificate
active
06223234
ABSTRACT:
RELATED APPLICATIONS
The subject matter of the U.S. Patent Application entitled “METHOD FOR THE HOT SWAP AND ADD OF INPUT/OUTPUT PLATFORMS AND DEVICES,” filed concurrently herewith, Application Ser. No. 09/118,716, contains related subject matter. In addition, this is a continuation-in-part of and incorporates by reference in their entirety the below listed U.S. patents and patent applications:
Ser. No. or
Attorney Docket No.
Patent No.
Filing Date
Title
MNFRAME.006A1
08/942,309
10/01/97
HOT ADD OF
DEVICES
SOFTWARE
ARCHITECTURE
MNFRAME.006A2
08/942,306
10/01/97
METHOD FOR
THE HOT ADD
OF DEVICES
MNFRAME.006A3
08/942,311
10/01/97
HOT SWAP OF
DEVICES
SOFTWARE
ARCHITECTURE
MNFRAME.006A4
08/942,457
10/01/97
METHOD FOR
THE HOT SWAP
OF DEVICES
MNFRAME.006A5
5,892,928
10/01/97
METHOD FOR
THE HOT ADD
OF A NETWORK
ADAPTER
ON A SYSTEM
INCLUDING A
DYNAMICALLY
LOADED
ADAPTER
DRIVER
MNFRAME.006A6
08/942,069
10/01/97
METHOD FOR
THE HOT ADD
OF A MASS
STORAGE
ADAPTER
ON A SYSTEM
INCLUDING A
STATICALLY
LOADED
ADAPTER
DRIVER
MNFRAME 006A7
08/942,465
10/01/97
METHOD FOR
THE HOT ADD
OF A NETWORK
ADAPTER
ON A SYSTEM
INCLUDING A
STATICALLY
LOADED
ADAPTER
DRIVER
MNFRAME.006A8
08/962,963
10/01/97
METHOD FOR
THE HOT ADD
OF A MASS
STORAGE
ADAPTER
ON A SYSTEM
INCLUDING A
DYNAMICALLY
LOADED
ADAPTER
DRIVER
MNFRAME.006A9
5,889,965
10/01/97
METHOD FOR
THE HOT SWAP
OF A NETWORK
ADAPTER
ON A SYSTEM
INCLUDING A
DYNAMICALLY
LOADED
ADAPTER
DRIVER
MNFRAME.006A10
08/942,336
10/01/97
METHOD FOR
THE HOT SWAP
OF A MASS
STORAGE
ADAPTER
ON A SYSTEM
INCLUDING A
STATICALLY
LOADED
ADAPTER
DRIVER
MNFRAME.006A11
08/942,459
10/01/97
METHOD FOR
THE HOT SWAP
OF A NETWORK
ADAPTER
ON A SYSTEM
INCLUDING A
STATICALLY
LOADED
ADAPTER
DRIVER
MNFRAME.006A12
08/942,458
10/01/97
METHOD FOR
THE HOT SWAP
OF A MASS
STORAGE
ADAPTER
ON A SYSTEM
INCLUDING A
DYNAMICALLY
LOADED
ADAPTER
DRIVER
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of the invention relates to I/O adapters in computer systems. More particularly, the field of invention relates to the hot add and swap of adapters and input/output platforms on computer systems.
2. Description of the Related Technology
As enterprise-class servers, which are central computers in a network that manage common data, become more powerful and more capable, they are also becoming ever more sophisticated and complex. For many companies, these changes lead to concerns over server reliability and manageability, particularly in light of the increasingly critical role of server-based applications. While in the past many systems administrators were comfortable with all of the various components that made up a standards-based network server, today's generation of servers can appear as an incomprehensible, unmanageable black box. Without visibility into the underlying behavior of the system, the administrator must “fly blind.” Too often, the only indicators the network manager has on the relative health of a particular server is whether or not it is running.
It is well-acknowledged that there is a lack of reliability and availability of most standards-based servers. Server downtime, resulting either from hardware or software faults or from regular maintenance, continues to be a significant problem. By one estimate, the cost of downtime in mission critical environments has risen to an annual total of $4.0 billion for U.S. businesses, with the average downtime event resulting in a $140 thousand loss in the retail industry and a $450 thousand loss in the securities industry. It has been reported that companies lose as much as $250 thousand in employee productivity for every 1% of computer downtime. With emerging Internet, intranet and collaborative applications taking on more essential business roles every day, the cost of network server downtime will continue to spiral upward.
A significant component of cost is hiring administration personnel. These costs decline dramatically when computer systems can be managed using a common set of tools, and where they don't require immediate attention when a failure occurs. Where a computer system can continue to operate even when components fail, and defer repair until a later time, administration costs become more manageable and predictable.
While hardware fault tolerance is an important element of an overall high availability architecture, it is only one piece of the puzzle. Studies show that a significant percentage of network server downtime is caused by transient faults in the I/O subsystem. These faults may be due, for example, to the device driver, the device firmware, or hardware which does not properly handle concurrent errors, and often causes servers to crash or hang. The result is hours of downtime per failure, while a system administrator discovers the failure, takes some action, and manually reboots the server. In many cases, data volumes on hard disk drives become corrupt and must be repaired when the volume is mounted. A dismount-and-mount cycle may result from the lack of “hot pluggability” or “hot plug” in current standards-based servers. Hot plug refers to the addition and swapping of peripheral adapters to an operational computer system. Diagnosing intermittent errors can be a frustrating and time-consuming process. For a system to deliver consistently high availability, it must be resilient to these types of faults.
In a typical PC-based server, upon the failure of an adapter, which is a printed circuit board containing microchips, the server must be powered down, the hot added adapter and adapter driver installed, the server powered back up and the operating system reconfigured.
However, various entities have tried to implement the hot plug of these adapters to a fault tolerant computer system. One significant difficulty in designing a hot plug system is protecting the circuitry contained on the adapter from being short-circuited when an adapter is added to a powered system. Typically, an adapter contains edge connectors which are located on one side of the printed circuit board. These edge connectors allow power to transfer from the system bus to the adapter, as well as supplying data paths between the bus and the adapter. These edge connectors fit into a slot on the bus on the computer system. A traditional hardware solution for “hot plug” systems includes increasing the length of at least one ground contact of the adapter, so that the ground contact on the edge connector is the first connector to contact the bus on insertion of the I/O adapter and the last connector to contact the bus on removal of the adapter. An example of such a solution is described in U.S. Pat. No.5,210,855 to Thomas M. Bartol.
U.S. Pat. No.5,579,491 to Jeffries discloses an alternative solution to the hot installation of I/O adapters. Here, each hotly installable adapter is configured with a user actuable initiator to request the hot removal of an adapter. The I/O adapter is first physically connected to a bus on the computer system. Subsequent to such connection a user toggles a switch on the I/O adapter which sends a signal to the bus controller. The signal indicates to the bus controller that the user has added an I/O adapter. The bus controller then alerts the user through a light emitting diode (LED) whether the adapter can be installed on the bus.
However, the invention disclosed in the Jeffries patent also contains several limitations. It requires the physical modification of the adapter to be hotly installed. Another limitation is that the Jeffries patent does not teach the hot addition of hot added adapter controllers or bus systems. Moreover, the Jeffries patent requires that before an I/O adapter is removed, another I/O adapter must either be free and spare or free and redundant. Therefore, if there was no free adapter, hot removal of an adapter is impossible until the user added another adapter to the computer system.
Hardware developers have recently created the Intelligent I/O (I
2
O) architecture to facilitate the development of hot added adapters for servers. Traditionally, a computer has one processor for h
Knobbe Martens Olson & Bear LLP
Micron Electronics Inc.
Ray Gopal C.
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