FAQ

4. What is Advanced Format?
Advanced Format is the term for 4K sector HDD or 512e HDD implementation.
5. How can performance issues and data risk be mitigated?
As stated before, the main reason for 512e performance issues is misalignment during writes.
Newer operating systems and applications are 512e-disk aware and minimize the incident of READ-
MODIFY-WRITE. Writing data on an aligned 4K boundary and in multiple of 4K bytes eliminates the READ-
MODIFY-WRITE operation.
As of the date of this document, most versions of Client and Enterprise Entry, Cloud and Archive drives do
not have power-loss-protection during READ-MODIFY-WRITE operations. An emergency power loss
during READ-MODIFY-WRITE operation of a physical sector (4K) could corrupt the adjacent logical sectors
(512 bytes) within the affected physical sector.
Enterprise drives incorporate an advanced non-volatile cache system to buffer the READ-MODIFY-WRITE
operation.
There are three versions of this non-volatile cache system:
a. Solid state non-volatile cache (NVC NOR flash or NVC NAND flash) using built-in spindle back-
EMF to power the flash in event of a power loss
b. Disk Media non-volatile cache which is also known as Media Based Cache (MBC or MC) using
a reserved area of the drive media to buffer the non-aligned writes from the host
c. Combination of 1 and 2
As of now, there are various non-volatile cache implementations:
RMW Cache System
Implemented in
None
Client, Entry, Cloud, and Archive HDDs
NVC solid state Vendor A&B* for
Enterprise drives
MBC/MC Vendor C for
Enterprise drives
NVC + MC Available as proto
for enterprise 512e drives but no plan for
production
*HDD vendors’ caching deployments are unique.
6. When is 4K sector HDD launching?
4K sector HDD started on notebook HDDs in Q3 ‘2010, on Desktop HDDs in 2011, selective Cloud
Enterprise HDDs in 2013 and mainstream Enterprise HDDs in 2014. Dell is leading this transition by
adopting these drives in PowerEdge, Power Vault, EqualLogic and Compellent systems.
7 4K Sector HDD FAQ