New blog series: One SSD Technology a Day

This entry is part 1 of 9 in the series One SSD Technology a Day

This entry is part 1 of 9 in the series One SSD Technology a Day

It’s become a tradition in the SQL blogs to start a month long series on a certain topic and try to blog every day. Today I want to start my first series on SSD technologies. It has been over a year [...]

A SSD Technology a Day (1) – Static Data Rotation

This entry is part 2 of 9 in the series One SSD Technology a Day

This entry is part 2 of 9 in the series One SSD Technology a Day

One of the main drawbacks of SSD  has been reliability. Every NAND cell has a certain prescribed number of Program/Erase (P/E) cycles and as data is being written to disk, chances are it will remain unchanged for weeks or months. That [...]

A SSD Technology a Day (2) – What’s the difference between SLC and MLC?

This entry is part 3 of 9 in the series One SSD Technology a Day

This entry is part 3 of 9 in the series One SSD Technology a Day

It’s time dissect the two main types of flash chips in order to understand why not all SSDs are created equal. What is after all the physical difference between SLC and MLC?

SLC stands for Single Level Cell and just like [...]

A SSD Technology a Day (3) – Program and Erase Cycle (P/E)

This entry is part 4 of 9 in the series One SSD Technology a Day

This entry is part 4 of 9 in the series One SSD Technology a Day

One of the limitations of flash memory is that while it can be read or programmed a byte or a word at a time in a random access fashion just like regular RAM, it can only be erased a “block” at [...]

A SSD Technology a Day (4) – Redundant Array of Independent Silicon Elements (RAISE)

This entry is part 5 of 9 in the series One SSD Technology a Day

This entry is part 5 of 9 in the series One SSD Technology a Day

RAISE is a technology developed by Sandforce that stands for  Redundant Array of Independent Silicon Elements. It is based on RAID ( Redundant Array of Independent Disks) technology  and is used to protect against write errors. Sandforce controllers that implement this technology [...]

A SSD Technology a Day (5) – Wear Leveling

This entry is part 6 of 9 in the series One SSD Technology a Day

This entry is part 6 of 9 in the series One SSD Technology a Day

Wear leveling is a technology used in Solid State Drive  controllers to prolong the service life of flash memory. As mentioned in the 2nd post of this blog series  What’s the difference between SLC and MLC? flash memories have limited endurance,measured [...]

A SSD Technology a Day (6) – CacheCade

This entry is part 7 of 9 in the series One SSD Technology a Day

This entry is part 7 of 9 in the series One SSD Technology a Day

CacheCade is a technology developed by LSI  for its MegaRAID Storage controllers. CacheCade software allows  you to mix inexpensive SATA or even SAS hard disk drives with up to 512GB of solid state storage capacity distributed over a few SSD drives, [...]

A SSD Technology a Day (7) – Intelligent Bad Block Management

This entry is part 8 of 9 in the series One SSD Technology a Day

This entry is part 8 of 9 in the series One SSD Technology a Day

In previous posts I talked about the wear and RAISE algorithms implemented by SSD controllers. One of the inevitable issues solid state memory is how to gracefully deal with bad blocks.

Bad blocks are flash memory blocks that contain one or [...]

A SSD Technology a Day (8) – eMLC and MLC-HET

This entry is part 9 of 9 in the series One SSD Technology a Day

This entry is part 9 of 9 in the series One SSD Technology a Day

In the 2nd post off this series we have explored the differences between SLC and MLC and saw that the main issue with MLC is endurance which in the past prevented their use for enterprise applications. Because of the increased capacity [...]