Control of multiple layer aggregation logical volume...

Details Control of multiple layer aggregation logical volume... Control of multiple layer aggregation logical volume...

2000-07-13

2003-10-21

Gaffin, Jeffrey (Department: 2182)

Data processing: database and file management or data structures

Database design

Data structure types

C711S162000, C711S111000, C711S112000, C711S114000, C713S001000, C713S002000

Reexamination Certificate

active

06636871

ABSTRACT:

FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT STATEMENT
This invention was not developed in conjunction with any Federally sponsored contract.
MICROFICHE APPENDIX
Not applicable.
The related application, Ser. No. 09/561,184, filed on Apr. 27, 2000. Benedict Micheal Rafanello, et al, is incorporated herein by reference in its entirely, including drawings, and hereby is made a part of this application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in the arts of computer disk media, formating of computer disks, organization of computer readable media by operating systems and device drivers, and the management of logical volumes of computer disks. In particular, this invention relates to improvements to the control of data and boot records stored in logical volumes when the logical volumes comprise multiple layers of aggregation.
2. Description of the Related Art
Persistent and mass data storage devices for computer systems, especially those employed in personal computers, are well known within the art. Many are disk-based, such as floppy disks, removable hard disk drives (“HDD”), and compact-disk read only memories (“CD-ROM”).
FIG. 1
shows a typical personal computer system (
1
) architecture, wherein a CPU (
2
) interfaces to a variety of I/O devices such as a keyboard (
3
), monitor or display (
5
) and a mouse (
4
). The CPU (
2
) also may interface to a number of storage peripherals including CD-ROM drives (
7
), hard disk drives (
6
), and floppy drives (
5
). Typically, floppy disk drives interface to the CPU via Integrated Drive Electronics (“IDE”) (
8
), but this interface may alternately be one of several other standard interfaces or a proprietary interface. The hard disk drives (
6
) and CD-ROM drives (
7
) may interface to the CPU (
2
) via an IDE or Small Computer System Interface (“SCSI”), as shown (
9
).
FIG. 2
shows a generalization of the hardware, firmware and software organization of a personal computer system (
20
). The hardware group (
21
) includes the persistent storage devices discussed supra, as well as other system hardware components such as a real-time clock, keyboard controller, display adapter, etc. A basic input/output system (“BIOS”) (
22
) provides the direct firmware control of these system components typically. An operating system (
24
) such as the IBM OS/2 operating system provides high level management of the system resources, including the multi-tasking or multi-threaded scheduling and prioritization of the system application programs (
25
). Drivers (
23
) provide specific high-level interface and control functions for specific hardware, such as a manufacturer and model-specific LAN interface card driver or CD-Rewritable (“CD-RW”) driver. This generalized view of the system also applies to systems on alternate, non-IBM-compatible platforms, such as workstations, which employ a variety of operating systems such as Microsoft Windows, UNIX or LINUX. This general organization of computer system resources and software functionality is well understood in the art.
Turning to
FIG. 3
, disk-based mass storage devices such as hard disk drives, floppy disks and CD-ROMS are based physically on a rotating storage platter (
30
). This platter may be made of flexible mylar, such as floppy disks, or more rigid platters made of aluminum, glass or plastic, such as hard disk drives and CD-ROMS. For magnetic media, one or both sides of the platter are coated with a magnetic layer capable of recording magnetic pulses from a read/write head. For optical media, data recording is made using changes in reflectivity of a band of light, which is then read by a laser-based head. Writable and Re-writable CD-ROM drives combine the technologies of magnetic disks and optical disks. In general, though, the organization of data on the disk is similar. The disk surfaces are divided into multiple concentric rings, or tracks (
31
). Some disk drives, such as hard disk drives, consist of multiple platters, in which case corresponding tracks on each platter are grouped into cylinders. Each track is divided into multiple sectors (
32
) in which data can be stored.
Turning to
FIG. 4
, we see a computer disk drive (
41
) represented as an ordered collection of sectors numbered
0
through “n”. The very first sector on the hard drive, sector zero, contains the Master Boot Record (“MBR”). The MBR contains partition definitions for the rest of the disk. TABLE 1 shows a sample partial MBR.
TABLE 1
Partition Table for 6 GB Drive
Start
End
Length
Partition
(cyl, side, sector)
(cyl, side, sector)
(sectors)
first
0, 1, 1
391, 254, 63
6297417
second
392, 0, 1
783, 254, 63
6297480
For the disk partitioning shown in TABLE 1, the MBR is located in the first sector on side
0
at cylinder
0
sector
1
. The MBR requires only one sector, but the entire track of 63 sectors is “blocked” for the use of the MBR, 62 sectors of side
0
cylinder
0
are left unused.
The partition table has entries in it defining two types of partitions: primary and extended. Conventional disk formatting schemes allow only one extended partition (
411
) to be defined. P
1
(
43
) and P
2
(
44
) are primary partitions. The order and locations of the primary and extended partitions may vary, but invariably there are entries in the partition table of the MBR which defines them.
The extended partition (
411
) is defined in the partition table in the MBR as a single partition using a single entry in the MBR partition table. Basically, this entry in the MBR just indicates to the computer operating system that inside of this extended partition can be found other partitions and partition definitions. The operating system typically assigns logical drive letters and/or logical volumes to these partitions, or groups of partitions.
In order to determine the size and location of the partitions within the extended partition, the operating system accesses the first sector of the extended partition which typically contains another boot record, known as an Extended Boot Record (“EBR”). The format of the EBR is similar to that of the MBR, and is also well known in the art.
FIG. 4
shows a first EBR (
45
), a second EBR (
47
), and a third EBR (
49
) within the extended partition (
411
). In practice, there may be fewer or more EBR's within an extended partition.
Each EBR contains a partition table similar to a MBR partition table. Conventionally for computer drives commonly used in personal computers and workstations, only two entries may be in use in each EBR. One entry will define a logical partition, and the second entry acts as a link, or pointer, to the next EBR.
FIG. 4
shows a pointer (
412
) from the second entry of the first EBR (
45
) to the beginning of the second EBR (
47
), and a similar pointer (
413
) from the second entry of the second EBR (
47
) to the beginning of the third EBR (
413
). The last EBR in the extended partition does not contain a pointer to a subsequent EBR, which indicates to the operating system that it is the last EBR in the extended partition. In this manner, the operating system can find and locate the definitions for an unlimited number of partitions or logical drives within the extended partition on a deterministic basis.
In each partition table entry, whether it be an EBR or an MBR, there are certain fields which indicate to the operating system the format, or file system, employed on the disk. For example, for DOS (“disk operating system”) systems, the field may indicate that the file system is File Allocation Table (“FAT”) formatted. Or, for systems which are running IBM's OS/2 operating system, the entry may indicate that the file system is High Performance File System (“HPFS”) formatted. There are a number of well-known file system formats in the industry, usually associated with the common operating systems for computers such as Microsoft's Windows, IBM's OS/2 and AIX, variants of UNIX, and LINUX. Using this field, the operating system may determine how to find and access data files stored within the partitions of the primary and ext

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