A recent post on Building Windows 8 blog by Bryan Matthew explains how Windows 8 will help us efficiently utilize large capacity drives. Our digital collections keep growing at an ever increasing rate – high resolution digital photography, high-definition home movies, and large music collections contribute significantly to this growth. Hard disk vendors have responded to this challenge by delivering very large capacity hard disk drives – a recent IDC market research report estimates that the maximum capacity of a single hard disk drive will increase to 8TB by 2015.
Even as hard disk drive vendors innovated to deliver very large capacity drives, two key challenges required focused attention:
Ensuring that the entire available capacity is addressable, so as to enable full utilization
Supporting the hard disk drive vendors in their effort to deliver more efficiently managed physical disks – 4K (large) sector sizes
Addressing all available capacity
To fully understand the challenges with addressing all available capacity on very large disks, we need to delve into the following concepts:
*The addressing method
*The disk partitioning scheme
*The firmware implementation in the PC – whether BIOS or UEFI
The addressing method
Initially, disks were addressed using the CHS (Cylinder-Head-Sector) method, where you could pinpoint a specific block of data on the disk by specifying which Cylinder, Head, and Sector it was on.The new addressing method was called Logical Block Addressing (LBA) – instead of referring to sectors using discrete geometry, a sector number (logical block address) was used to refer to a specific block of data on the disk.
The disk partitioning scheme
While LBA addressing theoretically allows arbitrarily large capacities to be accessed, in practice, the largest value of “n” can be limited by the associated disk partitioning scheme.The notion of disk partitioning can be traced back to the early 1980s – at the time, system implementers identified the need to divide a disk drive into several partitions (i.e. sub-portions), which could then be individually formatted with a file system, and subsequently used to store data. The Master Boot Record partition table (MBR) scheme was invented at the time, which allowed for up to 32-bits of information to represent the maximum capacity of the disk.As early as in the late 1990s, system implementers recognized the need to enable addressing greater than the 2.2TB limit (among other requirements). A group of companies collaborated to develop a scalable partitioning scheme called the GUID Partition Table (GPT), as part of the Unified Extensible Firmware Interface (UEFI) specification. Beginning with Windows Vista 64-bit, Windows has supported the ability to boot from a GPT partitioned hard disk drive with one key requirement – the system firmware must be UEFI. We’ve already talked about UEFI, so you know it can be enabled as a new feature of Windows 8 PCs.
Firmware implementation in the PC – BIOS or UEFI
PC vendors include firmware that is responsible for basic hardware initialization (among other things) before control is handed over to the operating system (Windows).Windows has consistently required modern UEFI firmware to be used in conjunction with the GPT scheme for boot disks.
Beginning with Windows 8, multiple new capabilities within Windows will necessitate UEFI. The combination of UEFI firmware + GPT partitioning + LBA allows Windows to fully address very large capacity disks with ease.
Bryan also adds,”Our partners are working hard to deliver Windows 8 based systems that use UEFI to help enable these innovative Windows 8 features and scenarios (e.g. Secure Boot, Encrypted Drive, and Fast Start-up). You can expect that when Windows 8 is released, new systems will support installing Windows 8 to, and booting from, a 3TB or bigger disk.” Here’s a preview:
Designing for large sector disks
Learning from some issues identified with prior versions of Windows, AF disks have been a key design point for new features and technologies in Windows 8; as a result, Windows 8 is the first OS with full support for both types of AF disks – 512e and 4K Native.
Issues addressed included the following:
Introduce new and enhance existing API to better enable applications to query for the physical sector size of a disk
Enhancing large-sector awareness within the NTFS file system, including ensuring appropriate sector padding when performing extending writes (writing to the end of the file)
Incorporating large-sector awareness in the new VHDx file format used by Hyper-V to fully support both types of AF disks
Enhancing the Windows boot code to work correctly when booting from 4K native disks.
NTFS in Windows 8 fully leverages capabilities delivered by our industry partners to efficiently support very large capacity disks. You can rest assured that your large-capacity storage needs will be well handled beginning with Windows 8 and NTFS.
Even as hard disk drive vendors innovated to deliver very large capacity drives, two key challenges required focused attention:
Ensuring that the entire available capacity is addressable, so as to enable full utilization
Supporting the hard disk drive vendors in their effort to deliver more efficiently managed physical disks – 4K (large) sector sizes
Addressing all available capacity
To fully understand the challenges with addressing all available capacity on very large disks, we need to delve into the following concepts:
*The addressing method
*The disk partitioning scheme
*The firmware implementation in the PC – whether BIOS or UEFI
The addressing method
Initially, disks were addressed using the CHS (Cylinder-Head-Sector) method, where you could pinpoint a specific block of data on the disk by specifying which Cylinder, Head, and Sector it was on.The new addressing method was called Logical Block Addressing (LBA) – instead of referring to sectors using discrete geometry, a sector number (logical block address) was used to refer to a specific block of data on the disk.
The disk partitioning scheme
While LBA addressing theoretically allows arbitrarily large capacities to be accessed, in practice, the largest value of “n” can be limited by the associated disk partitioning scheme.The notion of disk partitioning can be traced back to the early 1980s – at the time, system implementers identified the need to divide a disk drive into several partitions (i.e. sub-portions), which could then be individually formatted with a file system, and subsequently used to store data. The Master Boot Record partition table (MBR) scheme was invented at the time, which allowed for up to 32-bits of information to represent the maximum capacity of the disk.As early as in the late 1990s, system implementers recognized the need to enable addressing greater than the 2.2TB limit (among other requirements). A group of companies collaborated to develop a scalable partitioning scheme called the GUID Partition Table (GPT), as part of the Unified Extensible Firmware Interface (UEFI) specification. Beginning with Windows Vista 64-bit, Windows has supported the ability to boot from a GPT partitioned hard disk drive with one key requirement – the system firmware must be UEFI. We’ve already talked about UEFI, so you know it can be enabled as a new feature of Windows 8 PCs.
Firmware implementation in the PC – BIOS or UEFI
PC vendors include firmware that is responsible for basic hardware initialization (among other things) before control is handed over to the operating system (Windows).Windows has consistently required modern UEFI firmware to be used in conjunction with the GPT scheme for boot disks.
Beginning with Windows 8, multiple new capabilities within Windows will necessitate UEFI. The combination of UEFI firmware + GPT partitioning + LBA allows Windows to fully address very large capacity disks with ease.
Bryan also adds,”Our partners are working hard to deliver Windows 8 based systems that use UEFI to help enable these innovative Windows 8 features and scenarios (e.g. Secure Boot, Encrypted Drive, and Fast Start-up). You can expect that when Windows 8 is released, new systems will support installing Windows 8 to, and booting from, a 3TB or bigger disk.” Here’s a preview:
Designing for large sector disks
Learning from some issues identified with prior versions of Windows, AF disks have been a key design point for new features and technologies in Windows 8; as a result, Windows 8 is the first OS with full support for both types of AF disks – 512e and 4K Native.
Issues addressed included the following:
Introduce new and enhance existing API to better enable applications to query for the physical sector size of a disk
Enhancing large-sector awareness within the NTFS file system, including ensuring appropriate sector padding when performing extending writes (writing to the end of the file)
Incorporating large-sector awareness in the new VHDx file format used by Hyper-V to fully support both types of AF disks
Enhancing the Windows boot code to work correctly when booting from 4K native disks.
NTFS in Windows 8 fully leverages capabilities delivered by our industry partners to efficiently support very large capacity disks. You can rest assured that your large-capacity storage needs will be well handled beginning with Windows 8 and NTFS.
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