Windows 10 vs. 7 – Disk Drives NORTH TEXAS PC USER GROUP WINDOWS INSIDE-OUT SIG GLYNN BROOKS FEBRUARY 20, 2016

Today’s Topics What it takes to make a computer boot from a hard drive Why won’t a large capacity hard drive work in my old PC? Why won’t Windows 7 Backup and Restore work with my 4 TB external hard drive? Who makes the most reliable disk drives? 2/20/16NORTH TEXAS PC USER GROUP 2

Disk drive math The amount of disk space you can have in a computer depends on the operating system, the BIOS, and how the disk is formatted The old way of formatting a hard drive is called Master Boot Record (MBR) and has been around since DOS 2.0 (1983) The MBR is the first sector on a disk and can control up to 4 partitions Each partition is described by a 16-byte table entry, with 32-bit fields that define the Logical Block Address (LBA) for both where the partition starts and how large it is The largest number that can be written using 32 binary digits is 2 32, or 4,294,967,296. Each disk sector is 512 bytes, so the limit is 2.2TB per disk drive 2/20/16NORTH TEXAS PC USER GROUP 3

Master Boot Record Layout MBR is located the first sector on a disk Older PC BIOSs only support booting from MBR-formatted drives Older operating systems only support MBR-formatted drives Breaking the 2.2TB barrier requires several fundamental changes 2/20/16NORTH TEXAS PC USER GROUP 4

Breaking the 2.2TB barrier Overcoming the limitations of the Master Boot Record itself requires a new partitioning scheme Intel developed a replacement scheme is called GUID Partition Table or GPT GPT was part of the Extensible Firmware Interface (EFI) developed in 2000 GPT uses 64-bit LBA numbers so it can address a disk with a capacity of 9.4ZB or 9.4 billion terabytes 2/20/16NORTH TEXAS PC USER GROUP 5

Comparing MBR to GPT To boot from a GPT disk you need 1. a motherboard with a UEFI BIOS 2. an operating system that can boot from GPT 2/20/16NORTH TEXAS PC USER GROUP 6

Operating system GPT and GPT data disk support Operating SystemGPT Boot Capable?GPT Data Disk Capable? Windows XP (x86)No Windows XP (x64)NoYes 1 Windows Vista SP1 (x86)NoYes Windows Vista SP1 (x64)Yes 2 Yes Windows 7/8 (x86)NoYes Windows 7/8 (x64)Yes 2 Yes Linux UBUNTU SUSEYes 1 Yes with 3 rd party GPT loader 2 Only on systems with UEFI BIOS or UEFI Boot option 2/20/16NORTH TEXAS PC USER GROUP 7

When the stars don’t align… Due to a disk drive failure, needed to restore Windows 7 Pro image backup to a new disk drive Old disk drive was 2TB, new disk drive 3TB 1.Formatted 3TB disk drive with GPT 2.Restored disk image from backup, but computer would not boot 3.Determined motherboard did not have UEFI BIOS 4.Formatted 3TB drive with MBR, restored image backup 5.Computer now bootable, but lost 746 GB of storage 2/20/16NORTH TEXAS PC USER GROUP 8

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When the stars do align… UEFI BIOS – check! Compatible OS – check! 3TB+ hard drives – check! 2/20/16NORTH TEXAS PC USER GROUP 10

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Overall disk drive reliability All hard drives eventually wear out Case history: Backblaze data center studyBackblaze data center study Scope: 56,000 spinning hard drives in service during 2013 – /20/16NORTH TEXAS PC USER GROUP 12

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For further study… Upgrading and Repairing PCs, 21st Edition by Scott MuellerUpgrading and Repairing PCs, 21st Edition 2/20/16NORTH TEXAS PC USER GROUP 14