BUS610: Business Intelligence and Analytics

Flash Memory and How It Works

Flash Memory Structure

Flash memory is a type of storage device that uses electronic memory. Flash memory comes in a variety of ways and is known as a solid state storage device, meaning "there are not moving parts – everything is electronic instead of mechanical". Flash memory is used in many different devices, such as, computers, digital cameras, and mobile phones. Flash memory is a type of EEPROM chip. EEPROM stands for Electronically Erasable Programmable Read Only Memory. Inside of a flash memory chip is a grid of columns and rows with a cell. There are two transistors at each intersection and a thin oxide layer separates them. One transistor is known as a floating gate and the other one is known as the control gate. An electrical charge comes through the columns to the floating gate, which is called tunneling. The electrical charge causes the floating gate transistor to act like an electron gun. When the electrons get trapped on the other side of the thin oxide layer, closer to the control gate transistor, they act like a barrier between the two transistors. A cell sensor monitors the level of the charge. If the flow is above the 50% threshold, it has a value of 1 and if it is less, the value changes to 0. This is how information/data is being read on the flash memory device. Nowadays, flash memory has become the "dominant memory type wherever a system requires a significant amount of non-volatile, solid state storage".

Embedded Memory

Embedded memory is becoming an increasingly popular type of flash memory due to its small, convenient size. In today's society these types of memory can be found in phones, cameras, gaming devices, and even handheld devices like a GPS. In July 2013, Samsung announced that they developed the world's fastest embedded memory. These new products will be available in the 16, 32, and 64 GB sizes and feature an interface speed of 400 MB/s. This will increase user's abilities to multitask and perform tasks such as file transferring, browsing, and gaming. It also decreases the amount of time it takes to boot and load applications. This is a key factor in mobile devices where the physical space for additional storage or memory is limited. Memory cards are being used less and less when manufacturing mobile devices and smartphones. One limitation of the chip is the amount of memory it could store. The larger the chip, the more expensive the device is going to cost. Something else to consider is the problem that arises if the device breaks. Any valuable information that was stored on it is virtually irretrievable. That is one advantage of having a removable memory as discussed below.

Flash Memory Cards and Readers

Sony PlayStation Memory Card, made for gaming purposes only.

One of many different types of flash memory card that exists on the market.

If you want a fast and easy method of storing various types of media, you can't get much better than a flash memory card. Most modern portable devices contain a flash memory card because of its versatility and ease of use; cellphones, mp3 players, and digital cameras are but just a few examples of products that benefit from flash memory cards. However, just like how not all electronic devices can use the same type of battery, not all flash memory cards are compatible with every electronic portable device. That's why it's always important to read your user manual for instructions on the right card to purchase if you ever need a replacement.

Although the devices themselves can only use a specific flash memory card model, most modern desktop and notebook computers come with a flash memory card reader. The reader typically supports a number of different cards so you're able to organize and transfer the data from card to computer. If you aren't one of the fortunate few to have this reader built in to your computer, external models are sold at most stores that sell computer components and they're inexpensive.

Although a general-purpose flash memory card is used for most applications, there are other special memory cards that are made only for one unique purpose. For example, a professional compact flash memory card is designed for professional photographers for improved speed, quality, and storage capacities, taking telling a story through a picture to the next level. Also, special gaming flash memory cards are used for all game consoles, like Nintendo Wii and Sony PlayStation, to hold saved game data. Other special flash memory cards include HD memory cards for capturing high-definition videos; netbook memory cards to expand the storage of a netbook computer; and Wi-Fi enabled flash memory cards used to wirelessly upload photos from a camera.

USB Flash Drives

Sushiusb

The USB storage device is one that has been growing rapidly in popularity. It is a very user friendly form of storage. To save information to a USB flash drive, one simply must plug in the USB drive into the USB port (usually on the side or back of the computer), click the "save as" option on their project, then select the drive on their computer which represents the USB. Then one can eject the USB and take the saved information anywhere they need. USBs are quickly advancing as well. There are now ways that you can create an entire mobile computer, a fingerprint enabled secure file, and secure the use of your computer all with the use of a single USB flash drive. These new advances are sure to be hot on the market. USBs are high in demand right now, not just because of their technical abilities but also because of how you can choose a USB to fit into any lifestyle or match any personality. There are thousands of custom USBs available in stores and online. These range in colors, sizes, amounts of memory, and even shapes. USB flash drives are something that will definitely be here to stay for a while longer, even with the ever emerging cloud. USB flash drives are also very secure ways to store information. Since they are not connected to the Internet, they cannot be hacked, and some can be encrypted to prevent unauthorized access. The one down side to this use is the possibility of the flash drive being lost or stolen, but with proper precautions and organization, this can be avoided. Flash drives also preserve data and documents in a non-volatile state. As some specialized computers (such as theatre control boards) are prone to crashes and glitches, saving information on a flash drives prevents is from being corrupted or lost in the event of a system crash or other glitch. In simpler systems, flash drives can be used as the central storage point for a computer. While this may be inefficient on most machines, those that are single use and do not require large amounts of memory can benefit from this, as the system is flexible, and more memory space can be added as needed. However, the primary benefit of flash drives remains the mobility. Flash drives are an inexpensive and more secure alternative to the cloud and other means of Internet storage.

USB flash drive

USB drives are the perfect devices for transporting data and files. They are easy to use and their portability makes them incredibly convenient. In addition to storing files, they can also be used to run portable apps. Certain applications can be turned into portable versions of themselves. You can have access to various software applications to use on any computer. Free programs exist to convert applications to portable ones to, in essence, create a portable PC on a thumb drive. USB drives range in storage capacity from 2 GB to 4 TB. With 4 TB of storage in such a portable size, the limits to their use are virtually endless.

USB drives can be password protected, or some can even be secured using biometric features, like a finger print. There are some concern related to USB drive security. They can contain large amounts of information, and given their portability, they can be used for transporting files secretly. Anyone with access can simply plug a USB drive into a computer, copy files onto it, and remove them from the premises. USB drives carry an additional security risk in that they can contain malware that can be automatically launched using AutoPlay (which can be disabled) as soon as they are plugged in.

Solid State Drives

an example of a SSD

SSDs serve the same purpose as HDDs: they store data and files for long-term use. The difference is that SSDs use a type of memory called "flash memory," which is similar to RAM - but unlike RAM, which clears its data whenever the computer powers down, the data on an SSD persists even when it loses power. SSDs use a grid of electrical cells to quickly send and receive data. These grids are separated into sections called "pages," and these pages are where data is stored. Pages are clumped together to form "blocks". SSDs are called "solid-state" because they have no moving parts. SSD's are much faster than traditional hard disks (especially during random reads/writes) as they do not rely on mechanics to locate data (which becomes slow when data is located at different ends of a hard drive).

However, as with flash memory, SSD's can last only a finite amount of writes. As an SSD is used, the electrical charges within each of its data cells must be periodically reset. Unfortunately, the electrical resistance of each cell increases slightly with every reset, which increases the voltage necessary to write into that cell. Eventually, the required voltage becomes so high that the particular cell becomes impossible to write to. While SSD's include extra capacity (which cannot be seen by the user) solely to replace cells which become damaged this way, after a lot of writes (usually over 150 TB), the drive will fail. However the volumes of writes (reading alone isn't affected) required to do so is far out of the reach for most users.

The main drawback of a SSD as compared to a HDD is price; SSD's cost significantly more than a HDD, but the price difference is rapidly falling, and more and more computers now include a SSD by default.

Remote Storage

Network Storage

Remote storage is there to expand the disk space without hard disks and isn't connected to the computer directly but accessed through internet. That way you can access your files wherever you are, whenever you want, on your laptop or Smartphone or even a different computer. This is the basic concept of cloud storage. When you need to access a file, you open the file as usual but if the data isn't on your local volume, Remote Storage retrieves the information from a media library. When data is removed from a file, the logical size of the file remains but the physical size is reduce.

Being much faster and reliable than storage devices like CDs, DVDs, hard disks, and flash drives, an online remote storage provides protection against system errors like viruses, and enables one to recover lost data from any potential system crashes. Being critical to not only businesses, but home computer users as well, an online storage provides low-cost and easily accessible security for data management and storage. To assure maximum security, many online companies automatically backup systems on a daily, weekly, or monthly basis, to an "electronic vault". Also, unlike CDs or DVDs, using remote storage diminishes its vulnerability to damage and data loss. Living in today's high-tech society, the online remote storage system is definitely a very essential, yet affordable tool to assure that the countless amounts of data being saved on devices is still remediable after a computer failure.

Floppy Disk

The floppy disk drive was invented at IBM by Alan Shugart in 1967. The first floppy drives used an 8-inch disk that was later called a "diskette" as it got smaller, which evolved into the 5.25-inch disk that was used on the first IBM Personal Computer in August 1981. The 5.25-inch disks were dubbed "floppy" because the diskette packaging was a very flexible plastic envelope, unlike the rigid case used to hold today's 3.5-inch diskettes.

The floppy disk is an archaic physical external storage device that is now obsolete. There might be some banks that still use this storage medium, but any business or person who is considered computer literate does not use this system to store information. The down sides to floppy disks are that they are not compatible with any device that is contemporary, their security is non-existent, and the storage capacity is low - usually with a maximum of 1.44MB. The last version of a floppy disk was released in 1987 by IBM.

Holographic Storage

Holographic Data Storage

Holographic storage utilizes photo-sensitive media and innovative laser beam technology as a means of computer storage. This new storage method has the ability to store 1,000 DVD's into this 4 square inch storage device. This is unlike previous methods of data recording, such as magnetic and optical hard drives, which involve a rotating disk or simple 2D lasers. Instead, holographic storage begins with a single laser that is split into two separate parts -- the signal beam (carries data), and the reference beam (reconstructs hologram when prompted). A spatial light modulator is used to encode data for the signal beam, followed by a conversion of electronic data into binary code. It is then arranged into a specific pattern of dark and light pixels (representing zeros and ones), consisting of >1 million bits each. The signal and reference beams intersect, and a holographic image is created through a 3D refraction that is etched into the media. Advantages include a safe, fast, reliable, and portable system of storage. Disadvantages include expense, limited capacity, and recording fails. UV rays can also erase the data, which makes this method unstable in the long-term. Since the concept is still in its infancy, however, problems are expected to diminish greatly over time.

Storage area network

Storage area networks are clusters of high performance computers used to transfer huge amounts of data. SANs are also used for distributed processing applications requiring fast local network performance and designed specifically for data management. SANs move storage resources off the common user network and into an independent network. What this does is allow each server too access any shared storage extremely quickly, as if it was already attached to the server. Typically, a SAN is assembled using three components: cabling, host bus adaptors, and switches.

What makes a good storage area network? A SAN definitely needs to be indestructible and have a built-in protection against any potential harmful failure. If a SAN is vulnerable to failures and is unable to recover lost data, an enterprise may even go out of business! Secondly, a vast amount of storage capacity is another essential to a valuable storage network; since the number of devices connected to one host system may increase by time, the organization's storage and processing also needs to expand accordingly. A big advantage of using a good storage area network is the fact that even if all of one's system servers crash, the SAN remains online and provides disaster recovery.

Network Attached Storage

NAS

NAS is a type of dedicated file storage device typically connected by a wired networking connection, therefore only providing local area network users with storage. NAS supports file transfers, in which it will back up any data that appears in the form of files, such as email boxes, web content, remote system backups. The main advantage of a network attached storage is that network storage is no longer limited to the amount the computing device can hold. NAS devices typically look very box-like, without a keyboard or display. NAS products come in levels of capable storage space, drive capacity and drive scalability, often placed into one of 3 categories: Desktop NAS, devices aimed at small businesses and home users; Mid-market NAS, devices capable of running several hundred terabytes but not clustering; Enterprise NAS, devices that can store huge amounts of files, including virtual images, and being able to NAS cluster.

NAS vs SAN

Sharing via "The Cloud"

Both systems of storage serve different purposes for their clients. The main difference between SAN storage and NAS storage is the way that the systems interact with the network. A NAS network will behave in a way that makes it similar to any other network component. In contrast, the storage devices of a SAN network are found in a separate network but connected to the main one. Overall though, both systems are used for storage and over time the performance offered by both is becoming harder to distinguish. For example a SAN uses Fibre Channel interconnects while NAS makes Ethernet and TCP/IP connects, but now many SAN systems are switching over to those connection routes NAS systems use.