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I understand the typical MBR is 512B and the addressable space is 2TB (2^32 x 512B), this was related to the physical sector size of the storage device (HD) which made perfect sense, but what about IDEMA's new "Advance Format" new standard 4096B physical sector size on new storage devices... will the MBR now be 4096B with an addressable space of 16TB (2^32 x 4096B), or does it stay the same 512B?

Jordan Davis
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1 Answers1

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No, size of MBR stays 512 Bytes.

Advanced Format exposes disks with 4096B physical sector as eight 512B logical sectors which extends the limit of MBR to 17.6 TB

resourced & referenced from :

       https://superuser.com/a/866404/270195

       https://superuser.com/a/679800/270195

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  • Doesn't OS typically set the logical sector size? not the drive's controller (firmware)... – Jordan Davis Sep 21 '15 at 19:12
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    https://msdn.microsoft.com/en-us/library/windows/desktop/hh848035(v=vs.85).aspx --- `4 KB native: This media has no emulation layer and directly exposes 4 KB as its logical and physical sector size. The overall issue with this new type of media is that the majority of apps and operating systems do not query for and align I/Os to the physical sector size, which can result in unexpected failed I/Os.` – Jordan Davis Sep 21 '15 at 19:26
  • I'm almost positive the OS controls the logical not the drive's controller... but using 4k native and 4k logical changes the constructs for pretty much every application... Because right now almost every application is running using one of these new 4k sector drives is running in 512e mode (emulation-mode, 8 * 512B sectors) on the single 4k (physical sector) – Jordan Davis Sep 21 '15 at 19:29
  • Nvm it's typically the drive controller which controls it as per --> https://en.wikipedia.org/wiki/Advanced_Format#4Kn – Jordan Davis Sep 21 '15 at 19:34
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    Still does the MBR change in 4K Native Mode? – Jordan Davis Sep 21 '15 at 22:45
  • The drive's firmware determines the logical sector size. (In the case of external disks, this can be changed by the firmware in the enclosure.) The filesystem design, possibly in conjunction with format-time parameters, sets filesystem data structure sizes. The MBR is really just the first sector of the disk, so on a disk with 4096-byte sectors, the MBR is technically 4096 bytes in size; but AFAIK only the first 512 bytes of the MBR would be used in this case, since the MBR partition table format was designed with 512-byte sectors in mind. – Rod Smith Sep 22 '15 at 01:57
  • Yeah your right, you would have to rewrite the BIOS to resize the 512B to 4096B it is possible but pointless really when there is EUFI now and GPT which keeps the first sector "protected MBR" for backwards compatibility with older systems still using BIOS – Jordan Davis Sep 22 '15 at 05:01