Garbage Collection Algorithms in Flash-Based Solid State Drives

Solid state drives (SSDs)have emerged as faster and more reliable data storages over the last few years. Their intrinsic characteristics prove them to be more efficient as compared to other traditional storage media such as the Hard Disk Drives (HDDs). Issues such as write amplification, however, degrade the performance and lifespan of an SSD. This issue is in turn handled by the Garbage Collection (GC) algorithms that are put in place to supply free blocks for serving the writes being made to the flash-based SSDs and thus reduce the need of extra unnecessary writes. The LRU/FIFO, Greedy, Windowed Greedy and D choices algorithms have been described to lower write amplification for incoming writes which are different in nature. The performance of the GC algorithms varies based on factors such as pre-defined hot/cold data separation, hotness of data, uniform/non-uniform nature of incoming writes, the GC window size and the number of pages in each block of the flash memory package. Finally, it can be seen that the number of write frontiers so used, can dictate the separation of hot/cold data and increase the performance of a GC algorithm.

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DSFTL: An Efficient FTL for Flash Memory Based Storage Systems

Electronics ◽

10.3390/electronics9010145 ◽

2020 ◽

Vol 9 (1) ◽

pp. 145 ◽

Cited By ~ 1

Author(s):

Suk-Joo Chae ◽

Ronnie Mativenga ◽

Joon-Young Paik ◽

Muhammad Attique ◽

Tae-Sun Chung

Keyword(s):

Flash Memory ◽

Garbage Collection ◽

Hard Disk Drives ◽

Memory Device ◽

Data Block ◽

Disk Drives ◽

Hybrid Mapping ◽

Solid State Drives ◽

Dynamic Setting ◽

Very High

Flash memory is widely used in solid state drives (SSD), smartphones and so on because of their non-volatility, low power consumption, rapid access speed, and resistance to shocks. Due to the hardware features of flash memory that differ from hard disk drives (HDD), a software called FTL (Flash Translation Layer) was presented. The function of FTL is to make flash memory device appear as a block device to its host. However, due to the erase before write features of flash memory, flash blocks need to be constantly availed through the garbage collection (GC) of invalid pages, which incurs high-priced overhead. In the previous hybrid mapping schemes, there are three problems that cause GC overhead. First, operation of partial merge causes more page copies than operation of switch merge. However, many authors just concentrate on reducing operation of full merge. Second, the availability between a data block and a log block makes the space availability of the log block lower, and it also generates a very high-priced operation of full merge. Third, the space availability of the data block is low because the data block, which has many free pages, is merged. Therefore, we propose a new FTL named DSFTL (Dynamic Setting for FTL). In this FTL, we use many SW (sequential write) log blocks to increase operation of switch merge and to decrease operation of partial merge. In addition, DSFTL dynamically handles the data blocks and log blocks to reduce the operations of erase and the high-priced operation of full merge. Additionally, our scheme prevents the data block with many free pages from being merged to increase the space availability of the data block. Our extensive experimental results prove that our proposed approach (DSFTL) reduces the count of erase and increases the operation of switch merge. As a result, DSFTL decreases the garbage collection overhead.

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Data recovery in the case of fire-damaged Hard Disk Drives and Solid-State Drives

Forensic Science International: Reports ◽

10.1016/j.fsir.2021.100199 ◽

2021 ◽

pp. 100199

Author(s):

Denis Solodov ◽

Ilia Solodov

Keyword(s):

Solid State ◽

Hard Disk Drives ◽

Hard Disk ◽

Data Recovery ◽

Disk Drives ◽

Solid State Drives

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A Statistics-Based Data Placement Strategy for Hybrid Storage

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.644-650.1620 ◽

2014 ◽

Vol 644-650 ◽

pp. 1620-1624

Author(s):

Yuan Hua Yang ◽

Xian Bin Xu ◽

Shui Bing He ◽

Yu Hua Wen

Keyword(s):

Solid State ◽

Storage System ◽

Hard Disk Drives ◽

Hard Disk ◽

Data Access ◽

Data Placement ◽

Disk Drives ◽

Hybrid Storage ◽

Solid State Disks ◽

Storage Media

Although hard disk drives have been popular over several decades, there still exists the deficiency because of their slow speeds and high power consumptions. By contrast, flash-based solid state disks exhibit good performance and low power consumption. However, the limited lifetimes become a fatal flaw of solid state disks. In order to take full advantage of hard disk drives and solid state disks, we design a hybrid storage system to make them work in a complementary manner. Further, we propose a data placement scheme for this system to determine the data placement on the underlying solid state disks or hard disk drives based on the data access statistics. Experiment results show that the lifetime of solid state disks and the response time of the system can be significantly improved compared with the alone storage media.

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Development of Algorithm to Enhance the Security Feature of SATA on Solid State Drives

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.f1039.0886s19 ◽

2019 ◽

Vol 8 (6S) ◽

pp. 193-198

Keyword(s):

Solid State ◽

Data Storage ◽

User Authentication ◽

Hard Disk Drives ◽

Hard Disk ◽

Solid State Drives ◽

Flash Memories ◽

Storage Devices ◽

Storage Media ◽

Security Feature

Now a day’s quantity of data growing day by day accordingly the size of storage media is also increasing rapidly. In most of the storage devices flash memories are used one of them is Solid State drive. Solid state drives i.e. SSDs are non-volatile data storage devices which store determined data in NAND or NOR i.e. in flash memories, which provides similar functionality like traditional hard disk (HDD). This paper provides comparative study of Solid-state drives over Hard-disk drives. Also, implementation of algorithm to enhance the security of Solid-state drives in terms of user authentication, access control and media recovery from ATA security feature set. This algorithm fulfils security principles like Authentication and Data Integrity.

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