Texas Memory Systems

Last updated
Texas Memory Systems, Inc.
Company typeSubsidiary
Industry Solid State Storage
Digital signal processing
Founded1978;46 years ago (1978)
Headquarters
Houston, Texas
,
United States
Area served
35 countries [1]
Key people
Holly Frost, (Founder)
Dan Scheel (President) [2]
Products solid-state disks
Digital signal processors
Number of employees
< 100 (2011) [3]
Parent IBM
Website ramsan.com

Texas Memory Systems, Inc. (TMS) was an American corporation that designed and manufactured solid-state disks (SSDs) and digital signal processors (DSPs). TMS was founded in 1978 and that same year introduced their first solid-state drive, [4] followed by their first digital signal processor. In 2000 they introduced the RamSan line of SSDs. Based in Houston, Texas, they supply these two product categories (directly as well as OEM and reseller partners) to large enterprise and government organizations. [5] [6]

Contents

TMS has been supplying SSD products to the market longer than any other company. [7]

On August 16, 2012, IBM Corporation announced a definitive agreement to acquire Texas Memory Systems, Inc. This acquisition was completed as planned on October 1, 2012. [8] [9]

History

TMS was founded in 1978 in Houston, Texas by Holly Frost to address a need in seismic processing for the oil and gas industry. [1] The company's first product, the CMPS was a 16 Kilobyte (KB) custom SSD designed for Gulf Oil. [10] [1] [11]

SAM product line

Around 1988, TMS designed and sold hundreds of SAM-600/800 (Shared Attached Memory) storage enclosures mainly to the United States Department of Defense. These enclosures used 128 Megabytes (MB) of Dynamic random-access memory (DRAM) for data storage and several high-speed Emitter-coupled logic (ECL) inputs and outputs for data transfer. These systems were mainly used to acquire and analyze signals in real time. [12]

When the 1980s oil glut caused disruption in the oil and gas industry, TMS shifted focus away from SSDs and onto Digital signal processing products. [1] The previously-designed SAM storage systems were enhanced by adding in a custom designed DSP board. Prior to this added DSP capability, to analyze a signal, a user would have to send the signal to the SAM storage for staging, engage a separate system to perform digital signal processing, then store the result back to the SAM system for analyzing. Adding the DSP processor into the storage system itself meant that the data could be stored, processed, and analyzed all within the SAM system itself, relieving the host systems from processing duties. With this change in product focus, the SAM product line became known for DSP more than for SSD. The company would release more DSP systems under the SAM brand name in the 1990s: The SAM-2000 (1990), the SAM-300/350, and the SAM-450 (1997). [12] [11] The SAM-300, a 512 MB Solid State Disk, is notable as being a reference high-speed data store to optimize and benchmark other bottlenecks in computing systems, such as Network File System (NFS) and Local area networks (LANs), as other storage media at the time were not fast enough to expose these bottlenecks. [13]

In 2004, TMS partnered with StarGen (later acquired by Dolphin Interconnect Solutions) to integrate the SAM-650 DSP system with the StarFabric switched interconnect. The solution would support military-grade embedded applications by providing 192 Gigaflops of processing performance and 16 gigabits of bandwidth. [14]

XP product line

While the company was developing SAM systems that attached to multiple hosts, it also started developing DSP solutions on PCI cards to address the single-host market. The XP-15, XP-30, XP-35, and XP-100 products were released to the market and were architecturally modeled after the SAM systems. [12] The XP-30 and XP-35 utilize the TM-44 DSP, and the XP-100 utilize the TM-100 DSP. [15] Both of these DSP chips were custom designed ASICs from TMS. [16] [17] [18]

RamSan product line

RAM based products

RamSan-520 first RamSan branded solid state disk from Texas Memory Systems RamSan-520.jpg
RamSan-520 first RamSan branded solid state disk from Texas Memory Systems

In 2000, TMS started working on a new line of SSD products, the SAM-500/520, that would feature standard interfaces and protocols such as Fibre Channel. The SAM-520 was the first SSD product from TMS to use the RamSan brand. It featured 64 Gigabytes (GB) of DRAM for user data storage and up to 15 1 Gb/s Fibre Channel interfaces. [1]

TMS officially entered the commercial storage market [19] on April 10, 2001 with the announcement of the RamSan-210 which featured up to 32 GB of DRAM for user data storage, 4 Fibre Channel ports and promised 200,000 IOPs in a 2U rack-mountable enclosure. In order to assure that the user data written to DRAM would be persistent, in addition to writing user data to DRAM, the 210 also wrote user data to two mirrored hot swappable hard disk drives, a feature dubbed Triple-Mirror mode. [20] It also included redundant uninterruptible power supplies which would power the unit for a short time during a brownout, and allow the system to safely shut down in case of a total power loss. [21]

A product refresh followed on November 11, 2002 with the announcement of the RamSan-220 at Oracle OpenWorld in San Francisco, USA. The product doubled the Fibre Channel interface speed to 2  Gbps [22] and added a new mode of operation called DataSynch. DataSynch mode kept the hard disk drives offline and sent the read and write operations to memory only. In a power outage, the data from memory would be flushed to disk. [20] TMS would later release a 1 Terabyte (TB) solid state disk solution called Tera-RamSan on February 26, 2003 which was composed of 32 RamSan-220 units spread across two racks. The solution would consume 5 KW of power, support up to 2,000 Logical unit numbers (LUNs), and service over 2 million IOPs. A monitoring software dubbed Tera-RamSan at a Glance would allow the user to see system level status at a glance. [23]

On July 1, 2003 TMS announced the follow on RamSan-320. This product increased the height of the enclosure to 3U and added a third hard disk drive now in RAID-3 to backup user data. It provided up to 64 GB of DRAM for user data storage, up to eight 2 Gbps Fibre Channel ports, and increased the performance up to 250,000 IOPs. It also included a new optional patent-pending feature called Active Backup. [24] With Active Backup enabled, reads and writes would go only to memory just like DataSynch mode, but a background task would continually backup the data stored in memory to the hard disk drives offering the benefit of always having the user data backed up similar to Triple-Mirror mode. [25] Three weeks later, on July 29, 2003 TMS announced the RamSan-330 which included the same exact specifications as the 320, but optimized for a new use case. The 330 could be connected to servers, switches, and storage and would be transparent to the host operating system. It would automatically cache frequently accessed blocks, improving read and write performance of any attached storage. It offered user-configurable write-through, write-back, and read-ahead cache modes. [26] The 330 was demonstrated accelerating a Digi-Data STORM at CeBIT on March 22, 2004. [27] The 320 was refreshed and released as the RamSan-325 on November 9, 2004, and doubled the available capacity up to 128 GB. [28]

The product line was expanded with the addition of a new 1U entry level RamSan-120 on December 7, 2004. The 120 implemented the DRAM in a RAID configuration to increase reliability, and was only offered in an 8 GB configuration. It delivered 70,000 IOPs and up to 400 MB/s bandwidth [29]

DDR SDRAM based rackmount SSD RamSan-400.jpg
DDR SDRAM based rackmount SSD

A replacement for the 325, the RamSan-400 was announced on July 11, 2005. The interfaces were updated to support 4 Gb Fibre Channel, and the performance was improved to 3 GB/s bandwidth and 500,000 IOPs. The system added support for IBM Chipkill based ECC protection and increased the number of backup hard disk drives to 4. The 4 Gb Fibre Channel interfaces were made available to customers of older RamSan products as a miscellaneous equipment specification (MES) upgrade option [30]

A new 10 Gbps InfiniBand interface was announced on November 15, 2005 and was made generally available the following year. [31] [32]

A cost-reduced 3U enclosure, the RamSan-300 was announced on October 16, 2006. It could achieve a maximum performance of 200,000 IOPs and 1.5 GB/s bandwidth, and the memory configurations were limited to 16 or 32 GB. [33] This product, along with the RamSan-400, was the foundation for the Oracle Accelerator Kit which bundled a RamSan with QLogic InifiBand switches and Host Channel Adapters (HCA)s. [34]

Flash based products

TMS pivoted with the storage market and on September 17, 2007 announced a new 4U rack-mount enterprise solid state disk product, the RamSan-500, using NAND Flash memory as the primary user data storage medium instead of DRAM. The 500 used a 64 GB DDR memory cache in front of up to 2 TB of SLC flash storage. [35] [11] The flash storage was arrayed in nine RAID-3 protected hot swappable modules. [36] This product marked the beginning of development of the RamSan-OS, which was a custom designed flash management and storage infrastructure management suite implemented in both software and hardware. [37]

Flash based rackmount SSD RamSan-810.png
Flash based rackmount SSD
Flash based PCIe SSD RamSan-70.png
Flash based PCIe SSD

TMS Acquires Incipient IP

On September 8, 2009 TMS announced it had acquired all of the intellectual property and source code from Incipient, Inc., a privately held software company and leading provider of enterprise-class storage virtualization and automated data migration software founded in 2001 in Waltham, Massachusetts. [38] Incipient's flagship product was the Incipient Network Storage Platform (iNSP) software suite, a switch-resident storage virtualization software for Storage Area Network (SAN) environments first released in 2006. Incipient held at least five storage virtualization patents with the most significant patent, titled "Fast-path for performing data operations," covering split-path architecture for block level storage virtualization in scalable and highly-available switching fabrics. [39] In 2006, Incipient raised $24 million in Series D financing bringing the total capital raised to $79 million, and in 2008 raised an additional $15.6 million in Series E funding. [40] [41] The acquired software and IP would allow TMS to incorporate a storage virtualization solution into their portfolio by either clustering existing RamSan SSDs, enabling intelligent storage tiering with disk-based systems, or easing migration from disk-based systems. [42] In the announcement, TMS indicated that it had not acquired any interest in Incipient, Inc. and that the two companies would remain separate.

IBM Acquisition

On December 21, 2011, shortly after announcing their first high availability (HA) SSD product, the RamSan-720, TMS announced that they were putting themselves up for sale. The company was looking to be acquired by a large IT company such as EMC Corporation, Hewlett-Packard, IBM, Oracle Corporation or NetApp. [2] This coincides with a general consolidation in the industry such as SanDisk's acquisition of Pliant earlier in the year, a series of run-ups to IPO announcements such as Violin Memory, as well as new startups such as Pure Storage entering the market.

Less than one year later, on August 16, 2012, IBM announced they had entered into a definitive agreement to acquire TMS. The details of the deal were not disclosed. IBM planned to invest in and support the existing TMS product portfolio and integrate TMS technologies into a variety of solutions including storage, servers, software, and PureSystems offerings. At the time of the announcement, TMS employed approximately 100 people. The acquisition was completed on October 1, 2012, and the TMS products, services, and employees were integrated into the IBM Systems and Technology Group (STG). [43]

As part of the acquisition, TMS was subjected to the IBM Blue Wash process, [44] and the existing RamSan product line was re-released with IBM branding FlashSystem and an announcement of a $1B USD investment in research and development to design, create, and integrate new Flash solutions into its existing product portfolio. [45]

Products

Some TMS SSDs were specifically designed to accelerate Oracle applications. They are all part of the RamSan product line. [46]

TMS produces the following categories of SSDs:

Most of the TMS DSP products are part of the XP product line. [47]

Related Research Articles

<span class="mw-page-title-main">Computer memory</span> Computer component that stores information for immediate use

Computer memory stores information, such as data and programs, for immediate use in the computer. The term memory is often synonymous with the terms RAM,main memory, or primary storage. Archaic synonyms for main memory include core and store.

<span class="mw-page-title-main">Flash memory</span> Electronic non-volatile computer storage device

Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both use the same cell design, consisting of floating gate MOSFETs. They differ at the circuit level depending on whether the state of the bit line or word lines is pulled high or low: in NAND flash, the relationship between the bit line and the word lines resembles a NAND gate; in NOR flash, it resembles a NOR gate.

A RAM drive is a block of random-access memory that a computer's software is treating as if the memory were a disk drive. RAM drives provide high-performance temporary storage for demanding tasks and protect non-volatile storage devices from wearing down, since RAM is not prone to wear from writing, unlike non-volatile flash memory. They are in a sense the reverse of virtual memory: RAM drive uses a volatile fast memory as if it's a nonvolatile slow memory. Virtual memory is the opposite.

<span class="mw-page-title-main">Western Digital</span> American digital storage company

Western Digital Corporation is an American computer drive manufacturer and data storage company, headquartered in San Jose, California. It designs, manufactures and sells data technology products, including data storage devices, data center systems and cloud storage services.

Density is a measure of the quantity of information bits that can be stored on a given physical space of a computer storage medium. There are three types of density: length of track, area of the surface, or in a given volume.

Hierarchical storage management (HSM), also known as tiered storage, is a data storage and data management technique that automatically moves data between high-cost and low-cost storage media. HSM systems exist because high-speed storage devices, such as solid-state drive arrays, are more expensive than slower devices, such as hard disk drives, optical discs and magnetic tape drives. While it would be ideal to have all data available on high-speed devices all the time, this is prohibitively expensive for many organizations. Instead, HSM systems store the bulk of the enterprise's data on slower devices, and then copy data to faster disk drives when needed. The HSM system monitors the way data is used and makes best guesses as to which data can safely be moved to slower devices and which data should stay on the fast devices.

Input/output operations per second is an input/output performance measurement used to characterize computer storage devices like hard disk drives (HDD), solid state drives (SSD), and storage area networks (SAN). Like benchmarks, IOPS numbers published by storage device manufacturers do not directly relate to real-world application performance.

A hybrid drive is a logical or physical computer storage device that combines a faster storage medium such as solid-state drive (SSD) with a higher-capacity hard disk drive (HDD). The intent is adding some of the speed of SSDs to the cost-effective storage capacity of traditional HDDs. The purpose of the SSD in a hybrid drive is to act as a cache for the data stored on the HDD, improving the overall performance by keeping copies of the most frequently used data on the faster SSD drive.

In computing, external storage refers to non-volatile (secondary) data storage outside a computer's own internal hardware, and thus can be readily disconnected and accessed elsewhere. Such storage devices may refer to removable media, compact flash drives, portable storage devices, or network-attached storage. Web-based cloud storage is the latest technology for external storage.

<span class="mw-page-title-main">Solid-state drive</span> Computer storage device with no moving parts

A solid-state drive (SSD) is a solid-state storage device. It provides persistent data storage using no moving parts. It is sometimes called semiconductor storage device or solid-state device. It is also called solid-state disk because it is frequently interfaced to a host system in the same manner as a hard disk drive (HDD).

<span class="mw-page-title-main">IBM storage</span> Product portfolio of IBM

The IBM Storage product portfolio includes disk, flash, tape, NAS storage products, storage software and services. IBM's approach is to focus on data management.

<span class="mw-page-title-main">Phison</span> Taiwanese electronics company

Phison Electronics Corporation is a Taiwanese public electronics company that primarily designs, manufactures and sells controllers for NAND flash memory chips. These are integrated into flash-based products such as USB flash drives, memory cards, and solid-state drives (SSDs).

<span class="mw-page-title-main">Random-access memory</span> Form of computer data storage

Random-access memory is a form of electronic computer memory that can be read and changed in any order, typically used to store working data and machine code. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory, in contrast with other direct-access data storage media, where the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement.

A hybrid array is a form of hierarchical storage management that combines hard disk drives (HDDs) with solid-state drives (SSDs) for I/O speed improvements.

<span class="mw-page-title-main">IBM FlashSystem</span> IBM Storage enterprise system that store data on flash memory

IBM FlashSystem is an IBM Storage enterprise system that stores data on flash memory. Unlike storage systems that use standard solid-state drives, IBM FlashSystem products incorporate custom hardware based on technology from the 2012 IBM acquisition of Texas Memory Systems.

Solid-state storage (SSS) is non-volatile computer storage that has no moving parts; it uses only electronic circuits. This solid-state design dramatically differs from the commonly-used competing technology of electromechanical magnetic storage which uses moving media coated with magnetic material. Generally, SSS is much faster but more expensive for the same amount of storage.

<span class="mw-page-title-main">3D XPoint</span> Discontinued computer memory type

3D XPoint is a discontinued non-volatile memory (NVM) technology developed jointly by Intel and Micron Technology. It was announced in July 2015 and was available on the open market under the brand name Optane (Intel) from April 2017 to July 2022. Bit storage is based on a change of bulk resistance, in conjunction with a stackable cross-grid data access array, using a phenomenon known as Ovonic Threshold Switch (OTS). Initial prices are less than dynamic random-access memory (DRAM) but more than flash memory.

An open-channel solid state drive is a solid-state drive which does not have a firmware Flash Translation Layer implemented on the device, but instead leaves the management of the physical solid-state storage to the computer's operating system. The Linux 4.4 kernel is an example of an operating system kernel that supports open-channel SSDs which follow the NVM Express specification. The interface used by the operating system to access open-channel solid state drives is called LightNVM.

IBM FlashCore Modules (FCM) are solid state technology computer data storage modules using PCI Express attachment and the NVMe command set. They are offered as an alternative to industry-standard 2.5" NVMe SSDs in selected arrays from the IBM FlashSystem family, with raw storage capacities of 4.8 TB, 9.6 TB, 19.2 TB and 38.4 TB. FlashCore modules support hardware self-encryption and real-time inline hardware data compression up to 115.2 TB address space, without performance impact.

References

  1. 1 2 3 4 5 "History". Archived from the original on 2012-05-09. Retrieved 2020-03-31.
  2. 1 2 Mellor, Chris. "Texas Memory Systems longs to seduce 'larger player'". The Register. Retrieved 2020-03-31.
  3. ↑ Daugherty, Deon. "Strolling down 'memory' lane with high tech CEO Holly Frost". Houston Business Journal. Retrieved 2020-03-31.
  4. ↑ Klein, Dean (2009-02-09). "History of Digital Storage. Part 6: The RAM SSD and NAND". Micron. Retrieved 2010-07-02.
  5. ↑ "Texas Memory Systems main website". TMS. Retrieved 2011-08-01.
  6. ↑ "Texas Memory Systems". IBM. Retrieved 2010-07-02.
  7. ↑ Kerekes, Zsolt. "Texas Memory Systems". ACSL. Retrieved 2010-06-05.
  8. ↑ "IBM Announcement". IBM. Archived from the original on August 19, 2012. Retrieved 2012-08-17.
  9. ↑ "TMS Announcement". TMS. Retrieved 2012-08-17.
  10. ↑ Klein, Dean (2008-12-15). "History of Digital Storage" (PDF). Micron Technology, Inc. Retrieved 2020-03-31.
  11. 1 2 3 Polzin, K.D. "Time Matters". IBM. Retrieved 2020-03-31.
  12. 1 2 3 Frost, Holly (September 2010). "TMS History of Working With the US DoD" (PDF). Texas Memory Systems. Retrieved 2020-03-31.
  13. ↑ Faber, Theodore (January 1998). "Optimizing Throughput in a Workstation-based Network File System over a High Bandwidth Local Area Network". ACM SIGOPS Operating Systems Review. 32 (1): 29–40. doi:10.1145/280559.280565. S2CID   17728725 . Retrieved 10 April 2020.
  14. ↑ "Texas Memory Systems and StarGen join hands on embedded applications" . Retrieved 2021-02-16.
  15. ↑ "DSP ASIC". Archived from the original on 2012-04-20. Retrieved 2020-03-31.
  16. ↑ "XP-30". Archived from the original on 2012-05-09. Retrieved 2020-03-31.
  17. ↑ "XP-35". Archived from the original on 2012-05-09. Retrieved 2020-03-31.
  18. ↑ "XP-100". Archived from the original on 2012-05-09. Retrieved 2020-03-31.
  19. ↑ "Texas Memory Systems Enters Commercial Storage Market". 2001-05-10. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  20. 1 2 Baltazar, Henry (2003-02-03). "Storage Unit Delivers High Performance". eWeek. Retrieved 2020-03-31.
  21. ↑ "Texas Memory Systems Launches the RamSan 210 Solid State Disk". 2001-04-10. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  22. ↑ "Texas Memory Systems Announces General Availability of the RamSan-220". 2002-11-11. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  23. ↑ "Texas Memory Systems Announces the Tera-RamSan". 2003-02-26. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  24. ↑ USapplication 2005097288A1,Holzmann, Richard,"System and method for monitoring and non-disruptive backup of data in a solid state disk system",published 2005-05-05, assigned to Texas Memory Systems Inc
  25. ↑ "The World's Fastest Storage From Texas Memory Systems Boosts Application Performance Up To 25X". 2003-07-01. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  26. ↑ "Texas Memory Systems Launches Fastest RAID Cache Ever". 2003-07-29. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  27. ↑ "Solid State Disks to take CeBIT by STORM". 2004-03-16. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  28. ↑ "Texas Memory Systems Doubles The Capacity Of The "World's Fastest Storage" With Its New RamSan-325 Solid State Disk". 2004-11-09. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  29. ↑ "Texas Memory Systems Introduces 400 MB/s Entry-Level Solid State Disk". 2004-12-07. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  30. ↑ "Texas Memory Systems Introduces First 4-Gigabit, Half-A-Million I/O Per Second, Solid State Storage System". 2005-07-11. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  31. ↑ "Texas Memory Systems Demonstrates High-Performance InfiniBand-based Solid State Disk at Supercomputing Conference". 2005-11-15. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  32. ↑ "Texas Memory Systems Introduces First Solid State Disk for InfiniBand". 2006-11-15. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  33. ↑ "Texas Memory Systems Brings Affordable Solid State Technology to SMEs for Enhanced Database Performance". 2006-10-16. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  34. ↑ "Texas Memory Systems Introduces New Oracle Accelerator Kit – Supercomputer-Class InfiniBand Hardware for Oracle Grid Computing Environments". 2007-07-09. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  35. ↑ "Texas Memory Systems Introduces the World's Fastest Flash-Based Solid State Device and the First Enterprise-Class Cached Flash Storage System". 2007-09-17. Archived from the original on 2012-06-10. Retrieved 2020-03-31.
  36. ↑ "RamSan-500". Archived from the original on 2012-05-09. Retrieved 2020-03-31.
  37. ↑ "Texas Memory Systems Unveils the Ultimate "Application Accelerator" RamSan-820 (24-TB Useable, eMLC, 1U) High Availability Flash Storage Appliance and Its RamSan-OS (Operating System)". Texas Memory Systems. Retrieved 31 March 2020.
  38. ↑ "Texas Memory Systems expands its technology portfolio with the acquisition of patents and source code from Incipient". 2009-09-08. Archived from the original on 2012-06-10. Retrieved 2021-02-09.
  39. ↑ USpatent 7173929B1,TESTARDI, RICHARD,"Fast path for performing data operations",issued 2007-02-06, assigned to Incipient, Inc
  40. ↑ "Incipient, Inc. Secures Fifth Storage Virtualization Patent" . Retrieved 9 February 2021.
  41. ↑ "Incipient Inc. Lands $15,600,000 Series E Funding" . Retrieved 9 February 2021.
  42. ↑ "Texas Memory Systems Picks Incipient's Brain" . Retrieved 9 February 2021.
  43. ↑ "IBM Announcement". IBM. Archived from the original on October 3, 2012. Retrieved 2020-03-31.
  44. ↑ "What is Blue Wash?". IBM. Retrieved 2020-03-31.
  45. ↑ "IBM Drives Flash Technology Deeper into the Enterprise to Speed Big Data Analytics". IBM. 2013-04-11. Archived from the original on January 24, 2014. Retrieved 2020-03-31.
  46. ↑ "Products". TMS. Retrieved 2011-12-06.
  47. ↑ "Digital Signal Processing Line". TMS. Retrieved 3 April 2012.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.