MOD002556
24/02/2014
13:00-16:00
Non-volatile memory, nonvolatile memory, NVM or non-volatile storage is computer memory that can get back stored information even when not powered. Examples of non-volatile memory include read-only memory, flash memory, ferroelectric RAM (F-RAM), most types of magneticcomputer storage devices (e.g. hard disks, floppy disks, and magnetic tape), optical discs, and early computer storage methods such as paper tapeand punched cards.
Non-volatile memory is typically used for the task of secondary storage, or long-term persistent storage. The most widely used form of primary storagetoday is a volatile form of random access memory (RAM), meaning that when the computer is shut down, anything contained in RAM is lost. Unfortunately, most forms of non-volatile memory have limitations that make them unsuitable for use as primary storage. Typically, non-volatile memory either costs more or has a poorer performance than volatile random access memory.
http://en.wikipedia.org/wiki/Non-volatile_memory
RAM (Random Access Memory)
Random-access memory (RAM /ræm/) is a form of computer data storage. A random-access memory device allowsdata items to be read and written in roughly the same amount of time regardless of the order in which data items are accessed.[1] In contrast, with other direct-access data storage media such as hard disks, CD-RWs, DVD-RWs and the older drum memory, 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 delays.
Dynamic
Data will leak out even if power retained
Based on capacitors
Data must be refreshed about 1000 times per second
Static
Will retain data so long as power maintained
Based on transistors
Faster than DRAM but more expensive
Cache
Fastest form of SRAM and also most expensive
Mainly used for holding most recently used data
Infra-red Data Association
The Infrared Data Association (IrDA) is an industry driven interest group that was founded in 1993 by around 50 companies. IrDA provides specifications for a complete set of protocols for wireless infrared communications and the name "IrDA" also refers to that set of protocols. The main reason for using IrDA had been wireless data transfer over the “last one meter” using point and shoot principles. Thus, it has been implemented in portable devices such as mobile phones, laptops, cameras, printers, medical devices and many more. Main characteristics of this kind ofwireless optical communication is physically secure data transfer, Line-of-Sight (LOS) and very low bit error rate (BER) that makes it very efficient.
Bluetooth
Bluetooth is a wireless technology standard for exchanging data over short distances (using short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz[2]) from fixed and mobile devices, and building personal area networks (PANs). Invented by telecom vendor Ericsson in 1994,[3] it was originally conceived as a wireless alternative to RS-232 data cables. It can connect several devices, overcoming problems of synchronization.
Zigbee
ZigBee is a specification for a suite of high level communication protocols used to create personal area networks built from small, low-power digital radios. ZigBee is based on an IEEE 802.15 standard. Though low-powered, ZigBee devices can transmit data over long distances by passing data through intermediate devices to reach more distant ones, creating a mesh network; i.e., a network with no centralized control or high-power transmitter/receiver able to reach all of the networked devices. The decentralized nature of such wireless ad hoc networks make them suitable for applications where a central node can't be relied upon.
