5TH QUIZ 1ST part

1. Differentiate between storage devices and storage media.

STORAGE DEVICES is a device for recording (storing) information (data). Recording can be done using virtually any form of energy, spanning from manual muscle power in handwriting, to acoustic vibrations in phonographic recording, to electromagnetic energy modulating magnetic tape and optical discs.

A storage device may hold information, process information, or both. A device that only holds information is a recording medium. Devices that process information (data storage equipment) may either access a separate portable (removable) recording medium or a permanent component to store and retrieve information.

Electronic data storage is storage which requires electrical power to store and retrieve that data. Most storage devices that do not require vision and a brain to read data fall into this category. Electromagnetic data may be stored in either an analog or digital format on a variety of media. This type of data is considered to be electronically encoded data, whether or not it is electronically stored in a semiconductor device, for it is certain that a semiconductor device was used to record it on its medium. Most electronically processed data storage media (including some forms of computer data storage) are considered permanent (non-volatile) storage, that is, the data will remain stored when power is removed from the device. In contrast, most electronically stored information within most types of semiconductor (computer chips) microcircuits are volatile memory, for it vanishes if power is removed.

With the exception of barcodes and OCR data, electronic data storage is easier to revise and may be more cost effective than alternative methods due to smaller physical space requirements and the ease of replacing (rewriting) data on the same medium. However, the durability of methods such as printed data is still superior to that of most electronic storage media. The durability limitations may be overcome with the ease of duplicating (backing-up) electronic data.

STORAGE MEDIA Material constructed to hold digital data in conjunction with storage devices: data from e.g. computer, digital camera is written by storage device onto storage media. * May be magnetic e.g. Zip, Jaz, SuperDisk, CompactFlash disks; may be optical e.g. CD, DVD; or may be magneto-optical e.g. MO disks.
 

2. Identify the uses of tape, magnetic stripe cards, smart cards, microfilm and microfiche, and enterprise storage.

       THESE DEVICES are use as a STORAGE DEVICE in which stores data and more.STORAGE DEVICES are device for recording (storing) information (data). Recording can be done using virtually any form of energy, spanning from manual muscle power in handwriting, to acoustic vibrations in phonographic recording, to electromagnetic energy modulating magnetic tape and optical discs.

3. Describe the various types of flash memory storage: solid state drives, memory cards, USB flash drives, and ExpressCard modules.

TYPES OF FLASH MEMORY STORAGE:

Floating-gate transistor

In Floating-gate transistor,this flash memory each memory cell resembles a standard MOSFET, except the transistor has two gates instead of one. On top is the control gate (CG), as in other MOS transistors, but below this there is a floating gate (FG) insulated all around by an oxide layer. The FG is interposed between the CG and the MOSFET channel. Because the FG is electrically isolated by its insulating layer, any electrons placed on it are trapped there and, under normal conditions, will not discharge for many years. When the FG holds a charge, it screenselectric field from the CG, which modifies the threshold voltage (V_T) of the cell. During read-out, a voltage intermediate between the possible threshold voltages is applied to the CG, and the MOSFET channel will become conducting or remain insulating, depending on the V_T of the cell, which is in turn controlled by charge on the FG. The current flow through the MOSFET channel is sensed and forms a binary code, reproducing the stored data. In a multi-level cell device, which stores more than one bit per cell, the amount of current flow is sensed (rather than simply its presence or absence), in order to determine more precisely the level of charge on the FG. (partially cancels) the

NOR flash

In NOR gate flash, each cell has one end connected directly to ground, and the other end connected directly to a bit line.

This arrangement is called "NOR flash" because it acts like a NOR gate: when one of the word lines is brought high, the corresponding storage transistor acts to pull the output bit line low. NOR Flash continues to be the technology of choice for embedded applications requiring a discrete non-volatile memory device. The low read latencies characteristic of NOR devices allow for both direct code execution and data storage in a single memory product.

SOLID STATE DRIVES

SOLID STATE DRIVES (SSD) is a data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive. SSDs are distinguished from traditional hard disk drives (HDDs), which are electromechanical devices containing spinning disksread/write heads. SSDs, in contrast, use microchips which retain data in non-volatile memory chips and contain no moving parts. Compared to electromechanical HDDs, SSDs are typically less susceptible to physical shock, are silent, and have lower access time and latency, but are more expensive per gigabyte (GB) and typically support a limited number of writes over the life of the device. SSDs use the same interface as hard disk drives, thus easily replacing them in most applications. and movable

As of 2010, most SSDs use NAND-based flash memory, which retains memory even without power. SSDs using volatile random-access memory (RAM) also exist for situations which require even faster access, but do not necessarily need data persistence after power loss, or use external power or batteries to maintain the data after power is removed.^[update]

A hybrid drive combines the features of an HDD and an SSD in one unit, containing a large HDD, with a smaller SSD cache to improve performance of frequently accessed files. These can offer near-SSD performance in most applications (such as system startup and loading applications) at a lower price than an SSD. These are not suitable for data-intensive work, nor do they offer the other advantages of SSDs.