Instances where an inventor creates a complex electrotechnical device from scratch, relying solely on their own research, are extremely rare. Typically, various devices are born at the intersection of multiple technologies and standards developed by different people over time. For example, let's take a simple flash drive. This portable data storage device is based on non-volatile NAND memory and equipped with a built-in USB port, used for connecting the storage device to a client device. Therefore, to understand how such a device could appear on the market, it is necessary to trace the history of the invention of not only the memory chips themselves but also the corresponding interface, without which the familiar flash drives would simply not exist. Let's try to do that.
Semiconductor storage devices that support erasing recorded data have been around for almost half a century: the first EPROM was created by Israeli engineer Dov Froman back in 1971.
Dov Froman, developer of EPROM
Innovative for their time, ROMs were successfully used in the production of microcontrollers (such as Intel 8048 or Freescale 68HC11), but they proved to be utterly unsuitable for creating portable storage devices. The main problem with EPROM was the overly complex procedure for erasing information: to erase the data, the integrated circuit had to be exposed to ultraviolet light. It worked as follows: UV light photons provided excess electrons with enough energy to dissipate the charge on the floating gate.
EPROM chips were designed with special windows for data erasure, covered with quartz plates.
This introduced two significant inconveniences. Firstly, erasing data on such a chip could only be done adequately with a sufficiently powerful mercury lamp, and even then the process could take several minutes. In comparison, a regular fluorescent lamp would erase information over a period of years, and if such a microchip were exposed to direct sunlight, it would take weeks for complete erasure. Secondly, even if this process could somehow be optimized, selectively erasing a specific file was still impossible: information on EPROM was erased entirely.
The issues mentioned were resolved in the next generation of chips. In 1977, Eli Harari (who later founded SanDisk, one of the world's largest manufacturers of flash memory-based data storage) created the first prototype of EEPROM using auto-electronic emission technology — a type of ROM in which data erasure, like programming, was done electrically.
Eli Harari, founder of SanDisk, holding one of the first SD cards.
The operation principle of EEPROM was virtually identical to that of modern NAND memory: a floating gate was used as the charge carrier, and the transfer of electrons through dielectric layers occurred thanks to the tunnel effect. The memory cell organization was a two-dimensional array, which allowed data to be written and erased addressably. Additionally, EEPROM had a fairly good endurance: each cell could be rewritten up to 1 million times.
However, it wasn't all rosy here either. To enable electrical data erasure, an additional transistor had to be embedded in each memory cell to control the writing and erasing process. Now, each array element had to accommodate 3 conductors (1 column conductor and 2 row conductors), complicating the wiring of the matrix components and leading to significant scaling issues. Therefore, the creation of miniaturized and high-capacity devices was out of the question.
Since the finished model of semiconductor ROM already existed, further scientific research continued with the aim of creating chips capable of providing denser data storage. This endeavor culminated in success in 1984 when Fumio Masuoka, working at Toshiba, presented a prototype of non-volatile flash memory at the International Electron Devices Meeting held at the Institute of Electrical and Electronics Engineers (IEEE).
Fumio Masuoka, the "father" of flash memory
Interestingly, the name itself was coined not by Fumio, but by one of his colleagues, Shoji Ariizumi, who likened the data erasure process to the bright flash of lightning (from the English word "flash"). Unlike EEPROM, flash memory was based on MOS transistors with an additional floating gate situated between the p-layer and the control gate, allowing the removal of unnecessary components and enabling the creation of truly miniature chips.
The first commercial samples of flash memory were Intel chips manufactured using NOR (Not-Or) technology, production of which began in 1988. Similar to EEPROM, their matrices formed a two-dimensional array where each memory cell intersected a row and a column (the corresponding conductors connected to different transistor gates, while the source connected to a common substrate). However, by 1989, Toshiba introduced its version of flash memory, dubbed NAND. The array had a similar structure, but in each node, instead of one cell, several were now connected in series. Additionally, each line used two MOS transistors: a control transistor situated between the data line and the column of cells, and a ground transistor.
The higher density of configuration helped increase the chip's capacity, but it also complicated the read/write algorithm, which inevitably affected data transfer speeds. For this reason, the new architecture was unable to fully displace NOR, which found its application in the creation of embedded ROM. At the same time, NAND turned out to be ideally suited for the production of portable data storage devices — SD cards and, of course, flash drives.
By the way, the emergence of the latest devices was only made possible in 2000 when the price of flash memory significantly decreased, allowing the production of such devices for the retail market to be profitable. The world's first USB drive, the DiskOnKey, was developed by the Israeli company M-Systems: engineers Amir Ban, Dov Moran, and Oren Ogdan created this compact flash drive (which can be translated as 'disk-on-a-keychain' since the device's body featured a metal ring to allow it to be carried along with a set of keys). At that time, the miniature device capable of holding 8 MB of information, replacing around five 3.5-inch floppy disks, was priced at $50.
DiskOnKey — the world's first flash drive from the Israeli company M-Systems
Interesting fact: DiskOnKey had an official publisher in the USA, which was IBM. The 'localized' flash drives were identical to the originals, except for the logo on the front, which led many to mistakenly attribute the creation of the first USB drive to the American corporation.
DiskOnKey, IBM Edition
Following the original model, more capacious versions of DiskOnKey with 16 and 32 MB were released just a couple of months later, priced at $100 and $150 respectively. Despite the high cost, the combination of compact size, capacity, and high read/write speed (which turned out to be about ten times faster than that of standard floppy disks) appealed to many buyers. From that moment, flash drives began their triumphant march around the globe.
One warrior in the field: the battle for USB
However, a flash drive would not be a flash drive if the Universal Serial Bus specification had not appeared five years earlier — this is what the familiar abbreviation USB stands for. The history of the inception of this standard can be considered almost more interesting than the invention of flash memory itself.
Typically, new interfaces and standards in IT are the result of close collaboration among large companies, often even competitors, forced to combine efforts to create a unified solution that significantly simplifies the development of new products. This was the case, for example, with SD memory cards: the first version of the Secure Digital Memory Card was created in 1999 with the involvement of SanDisk, Toshiba, and Panasonic, and the new standard proved to be so successful that it was awarded industry recognition just a year later. Today, the SD Card Association includes over 1000 member companies, whose engineers are engaged in developing new specifications and enhancing existing ones that describe various parameters of flash cards.
At first glance, the story of USB is entirely similar to what happened with the Secure Digital standard. To make personal computers more user-friendly for the average consumer, hardware manufacturers needed, among other things, a universal interface for working with peripherals that supports "hot" plugging and requires no additional setup. Furthermore, creating a unified standard would help eliminate the "zoo" of ports (COM, LPT, PS/2, MIDI-port, RS-232, etc.), which would ultimately simplify and reduce the cost of developing new hardware, as well as implementing support for various devices.
Against the backdrop of these prerequisites, several companies that developed computer components, peripherals, and software—among the largest being Intel, Microsoft, Philips, and US Robotics—came together in an attempt to find a common denominator that would satisfy all market players. This common standard ultimately became USB. Microsoft's promotion of the new standard was significant, as they added interface support in Windows 95 (the necessary patch was included in Service Release 2) and later integrated the required driver in the final release of Windows 98. Simultaneously, on the hardware front, help came from an unexpected source: in 1998, the iMac G3 was unveiled—the first all-in-one computer from Apple, which exclusively used USB ports for connecting input devices and other peripherals (with the exception of a microphone and headphones). This 180-degree turnaround (since at the time Apple was focusing on FireWire) was largely due to Steve Jobs returning as CEO of the company a year earlier.
Original iMac G3 — the first 'USB computer'
In reality, the birth of the Universal Serial Bus was far more arduous, and the emergence of USB is largely due to the efforts of not just mega-corporations or a single R&D department within a company, but rather a specific individual—an Intel engineer of Indian descent named Ajai Bhatt.
Ajai Bhatt, the main ideologist and creator of the USB interface
Back in 1992, Ajai pondered that the term 'personal computer' didn't quite justify its name. Even a seemingly straightforward task like connecting a printer and printing a document required a certain level of expertise from the user (though, it seemed, why would an office worker, who only needs to create a report or a statement, need to understand complex technologies?) or forced them to turn to specialized professionals. If things remained as they were, PCs would never become a mass-market product, and thus, dreaming about surpassing ten million users worldwide would be futile.
Both Intel and Microsoft recognized the need for some standardization at the time. In particular, research in this area led to the emergence of the PCI bus and the concept of Plug&Play, meaning that Bhatt's initiative to focus efforts on finding a universal solution for peripheral connections should have been well-received. But that was not the case: Ajay's direct superior, after listening to the engineer, stated that the task was so complex that it was not worth spending time on it.
Ajay then sought support from parallel groups and found it in the form of one of Intel's distinguished researchers, Fred Pollack, who at that time was known for his work as the lead engineer on the Intel iAPX 432 and as the lead architect for the Intel i960, who gave the project the green light. However, this was only the beginning: the implementation of such a massive idea would be impossible without the involvement of other players in the market. From this moment on, true 'labor pains' began, as Ajay not only had to convince Intel's working group members of the potential of this idea, but also secure support from other hardware manufacturers.
It took almost a year and a half for numerous discussions, approvals, and brainstorming sessions. During this time, Ajay was joined by Bala Kadambi, who led the team responsible for developing PCI and Plug&Play, later becoming Intel's director of technology standards for input/output interfaces, and Jim Pappas, an expert on input/output systems. By the summer of 1994, they finally managed to form a working group and begin closer collaboration with other companies.
Over the following year, Ajay and his team met with representatives from more than 50 companies, including both small, specialized firms and giants like Compaq, DEC, IBM, and NEC. Work was continuous, literally 24/7: starting early in the morning, the trio attended numerous meetings, and at night they gathered in the nearest diner to discuss their plans for the next day.
While some may view such a working style as a waste of time, it yielded results: several multidisciplinary teams were formed, including engineers from IBM and Compaq specializing in computer components, chip developers from Intel and NEC, programmers who worked on creating applications, drivers, and operating systems (including from Microsoft), and many other specialists. It was the concurrent work on multiple fronts that ultimately helped create a truly flexible and universal standard.
Ajay Bhatt and Bala Kadambi at the European Inventor Award ceremony
Although Ajay's team managed to brilliantly address the political (achieving collaboration among various companies, including direct competitors) and technical (gathering numerous experts from different fields under one roof) challenges, there remained one more aspect that required close attention — the economic side of the issue. Here, substantial compromises had to be made. For instance, the desire to reduce the cost of the cable led to the conventional USB Type-A, which we still use today, becoming one-sided. Creating a truly universal cable would not only require redesigning the connector to make it symmetrical but also doubling the number of conductive wires, which would have resulted in doubling the cable's cost. However, now we have an enduring meme about the quantum nature of USB.
Other participants in the project also insisted on reducing costs. Jim Pappas often recalls a call from Betsy Tanner at Microsoft, who one day stated that, unfortunately, the company intended to abandon the use of the USB interface in the production of computer mice. The issue was that the planned data transfer rate of 5 Mbps was excessively high, and engineers were concerned that they would not meet the specifications for electromagnetic interference. This meant that such a "turbo mouse" could interfere with the normal functioning of both the PC and other peripheral devices.
In response to the reasonable argument about shielding, Betsy replied that additional insulation would increase the cost of the cable by 4 cents per foot, or 24 cents for a standard 1.8-meter (6-foot) wire, making the whole venture pointless. Moreover, the mouse cable had to remain flexible enough not to restrict hand movements. To address this, it was decided to introduce a distinction between high-speed (12 Mbps) and low-speed (1.5 Mbps) modes. The 12 Mbps buffer allowed for the use of splitters and hubs to connect multiple devices to one port simultaneously, while 1.5 Mbps was optimal for connecting mice, keyboards, and other similar devices to the PC.
Jim himself considers this story a stumbling block that ultimately ensured the success of the entire project. Without Microsoft's support, promoting the new standard in the market would have been significantly more challenging. Moreover, the compromise reached helped make USB considerably cheaper, and therefore more attractive in the eyes of peripheral manufacturers.
What's in a name, or The Madness of Rebranding
Since we are discussing USB drives today, let's also clarify the situation regarding the versions and speed characteristics of this standard. It's not as straightforward as it may seem at first glance, as since 2013, the USB Implementers Forum has made every effort to thoroughly confuse not only ordinary consumers but also IT professionals.
In the past, everything was quite simple and logical: we had a slow USB 2.0 with a maximum throughput of 480 Mbps (60 MB/s) and a USB 3.0 that was ten times faster, with a data transfer rate reaching 5 Gbps (640 MB/s). Thanks to backward compatibility, a USB 3.0 device can be connected to a USB 2.0 port (or vice versa), but in this case, the reading and writing speed will be limited to 60 MB/s, as the slower device becomes a "bottleneck."
On July 31, 2013, USB-IF introduced considerable confusion into this streamlined system: on this day, a new specification—USB 3.1—was announced. And no, it is not merely about versioning that has seen fractional numbers before (although for the sake of fairness, it should be noted that USB 1.1 was a refined version of 1.0, not something qualitatively new), but rather that the USB Implementers Forum decided for some reason to rename the old standard. Watch closely:
- USB 3.0 became USB 3.1 Gen 1. This is pure renaming: no improvements were made, and the maximum speed remains the same—5 Gbps and not a bit more.
- The truly new standard became USB 3.1 Gen 2: the transition to 128b/132b encoding (previously 8b/10b was used) in full-duplex mode allowed for a doubling of the interface's bandwidth, achieving an impressive 10 Gbps, or 1280 MB/s.
But USB-IF thought that was not enough, so they decided to add a couple of alternative names: USB 3.1 Gen 1 became SuperSpeed, and USB 3.1 Gen 2 became SuperSpeed+. This step is quite justified: for retail customers, who are far removed from the world of computer technology, it is much easier to remember a catchy name than a sequence of letters and numbers. Here, everything is intuitive: we have a "SuperSpeed" interface that, as one can conclude from the name, is very fast, and a "SuperSpeed+" interface that is even faster. But why such a specific rebranding of generation indices was necessary remains utterly unclear.
However, there is no limit to imperfection: on September 22, 2017, with the publication of the USB 3.2 standard, the situation worsened even further. Let's start with the good news: the bidirectional USB Type-C connector, whose specifications were developed for the previous generation of the interface, allowed for doubling the maximum bandwidth of the bus by using duplicate pins as a separate data channel. Thus, USB 3.2 Gen 2×2 emerged (why it couldn't be called USB 3.2 Gen 3 is still a mystery), operating at speeds of up to 20 Gbps (2560 MB/s), which, in particular, found its application in the production of external solid-state drives (this is the type of port equipped on high-speed WD_BLACK P50, aimed at gamers).
And all would be well, but in addition to the introduction of the new standard, there was also a renaming of the previous ones: USB 3.1 Gen 1 became USB 3.2 Gen 1, while USB 3.1 Gen 2 turned into USB 3.2 Gen 2. Even the marketing names underwent changes, with USB-IF moving away from the previously adopted concept of 'intuitively understandable and no numbers': instead of labeling USB 3.2 Gen 2×2 as, for example, SuperSpeed++ or UltraSpeed, they decided to add a direct indication of the maximum data transfer speed:
- USB 3.2 Gen 1 became SuperSpeed USB 5Gbps,
- USB 3.2 Gen 2 — SuperSpeed USB 10Gbps,
- USB 3.2 Gen 2×2 — SuperSpeed USB 20Gbps.
So how do you navigate this USB standard zoo? To make your life easier, we've created a summary reference table that will make it simple to match different versions of interfaces.
Standard Version
Marketing Name
Speed, Gbps
USB 3.0
USB 3.1
USB 3.2
USB 3.1 Version
USB 3.2 Version
USB 3.0
USB 3.1 Gen 1
USB 3.2 Gen 1
SuperSpeed
SuperSpeed USB 5Gbps
5
–
USB 3.1 Gen 2
USB 3.2 Gen 2
SuperSpeed+
SuperSpeed USB 10Gbps
10
–
–
USB 3.2 Gen 2×2
–
SuperSpeed USB 20Gbps
20
Diversity of USB drives using SanDisk products as an example
But let's return directly to the subject of today's discussion. Flash drives have become an integral part of our lives, acquiring numerous modifications, sometimes quite peculiar. The most comprehensive understanding of the capabilities of modern USB drives can be gained from the portfolio of SanDisk.
All current SanDisk flash drive models support the USB 3.0 data transfer standard (also known as USB 3.1 Gen 1, USB 3.2 Gen 1, or SuperSpeed — just like in the movie 'Moscow Does Not Believe in Tears'). Among them, you can find both classic flash drives and more specialized devices. For instance, if you want to acquire a compact universal storage device, it makes sense to pay attention to the SanDisk Ultra line.
SanDisk Ultra
With six variations of different capacities (from 16 to 512 GB), it's easy to choose the optimal option based on your needs without overpaying for extra gigabytes. The data transfer speed of up to 130 MB/s allows for quick downloads, even of large files, while the convenient retractable casing reliably protects the connector from damage.
For fans of elegant designs, we recommend the SanDisk Ultra Flair and SanDisk Luxe USB drives.
SanDisk Ultra Flair
Technically, these flash drives are completely identical: both series have a data transfer speed of up to 150 MB/s, and each includes 6 models with capacities ranging from 16 to 512 GB. The differences lie only in the design: Ultra Flair features an additional structural element made of durable plastic, while the Luxe version's casing is entirely made of aluminum alloy.
SanDisk Luxe
In addition to their striking design and high data transfer speed, the mentioned drives have one more interesting feature: their USB connectors are a direct continuation of the monolithic casing. This design ensures an extremely high level of protection for the flash drive: it is practically impossible to accidentally break such a connector.
Besides full-size drives, the SanDisk collection also includes 'plug and forget' solutions. We're talking, of course, about the ultra-compact SanDisk Ultra Fit, which measures only 29.8 × 14.3 × 5.0 mm.
SanDisk Ultra Fit
This little guy barely protrudes from the surface of the USB port, making it an ideal solution for expanding the storage of client devices, whether it's an ultrabook, car audio system, Smart TV, gaming console, or single-board computer.
Among the most interesting offerings in the SanDisk collection are the Dual Drive and iXpand USB flash drives. Despite their design differences, both families share a common concept: these flash drives feature two ports of different types, allowing for data transfer between PCs or laptops and mobile devices without needing additional cables and adapters.
The Dual Drive family is designed for use with smartphones and tablets running the Android operating system that support OTG technology. It includes three lines of flash drives.
The compact SanDisk Dual Drive m3.0, in addition to USB Type-A, is equipped with a microUSB connector, ensuring compatibility with devices from previous years as well as low-end smartphones.
SanDisk Dual Drive m3.0
The SanDisk Ultra Dual Type-C, as the name suggests, features a more modern dual-sided connector. The drive itself has become larger and bulkier, but this body design provides better protection, making it harder to lose the device.
SanDisk Ultra Dual Type-C
If you’re looking for something more elegant, we recommend considering the SanDisk Ultra Dual Drive Go. These drives operate on the same principle as the previously mentioned SanDisk Luxe: a full-sized USB Type-A connector is part of the flash drive's housing, preventing breakage even with careless handling. The USB Type-C connector, on the other hand, is well-protected by a swivel cap that also includes a loop for a keychain. This design makes the flash drive truly stylish, compact, and reliable.
SanDisk Ultra Dual Drive Go
The iXpand series is completely similar to the Dual Drive, except that the USB Type-C has been replaced with the proprietary Apple Lightning connector. The most unique device in the series is the SanDisk iXpand: this flash drive features an original design in the form of a loop.
SanDisk iXpand
It looks striking, and you can thread a strap through the resulting loop to wear the drive, for example, around your neck. Additionally, using such a flash drive with an iPhone is much more convenient than with a traditional one: when connected, much of the body rests behind the smartphone, pressing against its back cover and helping to minimize the risk of damaging the plug.
If this design does not suit you for any reason, it makes sense to consider the SanDisk iXpand Mini. Technically, it is still the same iXpand: the lineup also includes four drives of 32, 64, 128, or 256 GB, with a maximum data transfer speed of 90 MB/s, which is sufficient even for viewing 4K videos directly from the flash drive. The only difference is in the design: the loop is gone, but a protective cap for the Lightning connector has been added.
SanDisk iXpand Mini
The third representative of the illustrious family, the SanDisk iXpand Go, is a twin brother of the Dual Drive Go: their sizes are practically identical, and both drives feature a rotating cap, albeit with slightly different designs. This line includes 3 models: 64, 128, and 256 GB.
SanDisk iXpand Go
The range of products under the SanDisk brand is by no means limited to the listed USB drives. You can explore other devices by the renowned brand on .
Source: habr.com
