Integrated-circuit implementation of a storage-shelf router and a path controller card for combined use in high-availability mass-storage-device shelves and that support virtual disk formatting
View Patent ↗One embodiment of the present invention is a virtual disk formatting system includes a mass-storage device having physical sectors that each contains a data payload of a first data length and additional information, including one or more of a sector number, error-detection, and error-correction information and a virtual disk interface to the mass-storage device, implemented in an integrated circuit, that maps access operations, received from external entities by the virtual disk interface, directed to a virtual disk having virtual sectors containing a data payload of a second data length by contiguously mapping an array of virtual-sector data payloads to a contiguous array of physical-sector data payloads without introducing padding data into physical-sector data payloads or into virtual-sector data payloads to align the initial bytes of virtual sectors and physical sectors.
1. A virtual disk formatting system comprising:
a number of mass-storage devices having physical sectors of a first sector length; and
a routing component that provides a virtual disk interface to the mass-storage components by mapping access operations, received from external entities, directed to a virtual disk having virtual sectors of a second sector length to the number of mass-storage devices without introducing padding data into physical sectors or into virtual sectors to align the initial bytes of virtual sectors and physical sectors.
2. The virtual disk formatting system of claim 1 wherein the routing component is an integrated-circuit storage-shelf router.
3. The virtual disk formatting system of claim 2 wherein the storage-shelf router provides a fibre-channel-disk-based virtual disk formatting interface to external entities and maps fibre-channel-disk-based access operations to a number of ATA disk drives included in a storage shelf containing the storage-shelf router.
4. The virtual routing system of claim 1 wherein the routing component includes a processor and firmware/software programs that carry out virtual disk formatting.
5. The virtual disk formatting system of claim 1 wherein virtual sectors are mapped onto contiguous physical sectors, allowing the physical sector and byte address of the first byte of a virtual sector to be calculated, when the second sector length is greater than the first sector length, as:
f
s
l
=
first
sector
length
s
s
l
=
second
sector
length
modulus
=
(
smallest
number
evenly
divisible
by
both
f
s
l
and
s
s
l
)
/
s
s
l
difference
=
s
s
l
-
f
s
l
physical
sector
=
virtual
sector
+
(
virtual
sector
modulus
)
physical
byte
address
=
remainder
(
virtual
sector
modulus
)
×
difference
and, when the second sector length is less than the first sector the physical sector and byte address of the first byte of a virtual sector is calculated, as:
f
s
l
=
first
sector
length
s
s
l
=
second
sector
length
modulus
=
(
smallest
number
evenly
divisible
by
both
f
s
l
and
s
s
l
)
/
s
s
l
difference
=
f
s
l
-
s
s
l
physical
sector
=
virtual
sector
+
(
virtual
sector
modulus
)
physical
byte
address
=
remainder
(
f
s
l
-
remainder
(
virtual
sector
modulus
)
×
difference
)
/
f
s
l
.
6. The virtual disk formatting system of claim 5 wherein, when the modulus and difference are both evenly divided by 2, the division and multiplication operations can be replaced with shift operations, and the remainder operation can be replaced by a bit-wise and operation.
7. A virtual disk formatting system comprising:
a mass-storage device having physical sectors that each contains a data payload of a first data length and additional information, including one or more of a sector number, error-detection, and error-correction information; and
a virtual disk interface to the mass-storage device, implemented in an integrated circuit, that maps access operations, received from external entities by the virtual disk interface, directed to a virtual disk having virtual sectors containing a data payload of a second data length by contiguously mapping an array of virtual-sector data payloads to a contiguous array of physical-sector data payloads without introducing padding data into physical-sector data payloads or into virtual-sector data payloads to align the initial bytes of virtual sectors and physical sectors.
8. The virtual disk formatting system of claim 1 wherein the virtual disk interface is incorporated within an integrated-circuit storage-shelf router.
9. The virtual disk formatting system of claim 8 wherein the storage-shelf router provides a fibre-channel-disk-based virtual disk formatting interface to external entities and maps fibre-channel-disk-based access operations to a number of ATA disk drives included in a storage shelf containing the storage-shelf router.
10. The virtual disk formatting system of claim 8 wherein storage-shelf router includes a processor and firmware/software programs that carry out virtual disk formatting.
11. The virtual disk formatting system of claim 7 wherein contiguous virtual sectors are mapped onto contiguous physical sectors, allowing the physical sector and byte address of the first byte of a virtual sector to be calculated, when the second sector length is greater than the first sector length, as:
f
s
l
=
first
sector
length
s
s
l
=
second
sector
length
modulus
=
(
smallest
number
evenly
divisible
by
both
f
s
l
and
s
s
l
)
/
s
s
l
difference
=
s
s
l
-
f
s
l
physical
sector
=
virtual
sector
+
(
virtual
sector
modulus
)
physical
byte
address
=
remainder
(
virtual
sector
modulus
)
×
difference
and, when the second sector length is less than the first sector the physical sector and byte address of the first byte of a virtual sector is calculated, as:
f
s
l
=
first
sector
length
s
s
l
=
second
sector
length
modulus
=
(
smallest
number
evenly
divisible
by
both
f
s
l
and
s
s
l
)
/
s
s
l
difference
=
f
s
l
-
s
s
l
physical
sector
=
virtual
sector
+
(
virtual
sector
modulus
)
physical
byte
address
=
remainder
(
f
s
l
-
remainder
(
virtual
sector
modulus
)
×
difference
)
/
f
s
l
.
12. The virtual disk formatting system of claim 11 wherein, when the modulus and difference are both evenly divided by 2, the division and multiplication operations can be replaced with shift operations, and the remainder operation can be replaced by a bit-wise and operation.