In computer hardware, GUID Partition Table (GPT) is a standard for the layout of the partition table on a physical hard disk. Although it forms a part of the Extensible Firmware Interface (EFI) standard (Intel's proposed replacement for the PC BIOS), it is also used on some BIOS systems because of the limitations of MBR partition tables, which use 32 bits for storing logical block addresses and size information. For disks with 512-byte sectors, the MBR partition table entries allow up to a maximum of 2.20 TB (2.20 × 1012 bytes) or 2 TiB−512 bytes (2,199,023,255,040 bytes or 4,294,967,295 (232−1) sectors × 512 (29) bytes per sector). GPT allocates 64 bits for logical block addresses and therefore allows a maximum disk and partition size of 264−1 sectors. For disks with 512-byte sectors, that would be 9.4 ZB (9.4 × 1021 bytes) or 8 ZiB−512 bytes (9,444,732,965,739,290,426,880 bytes or 18,446,744,073,709,551,615 (264−1) sectors × 512 (29) bytes per sector).
As of 2010, most current operating systems support GPT, although some (including Mac OS X and Windows) only support booting to GPT partitions on systems with EFI firmware.
Read more about GUID Partition Table: History, Features, Legacy MBR (LBA 0), Partition Table Header (LBA 1), Partition Entries, Operating System Support of GPT, Partition Type GUIDs
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“O ye wha are sae guid yoursel,
Sae pious and sae holy,
Ye’ve nought to do but mark and tell
Your neebour’s fauts and folly!”
—Robert Burns (1759–1796)
“The best thing about Sassy Seats is that grandmothers cannot figure out how they work and are in constant fear of the child’s falling. This often makes them forget to comment on other aspects of the child’s development, like why he is not yet talking or is still wearing diapers. Some grandmothers will spend an entire meal peering beneath the table and saying, “Is that thing steady?” rather than, “Have you had a doctor look at that left hand?””
—Anna Quindlen (20th century)