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A Review on Live Memory Acquisition Approaches for Digital Forensics
Published in Mukesh Kumar Awasthi, Ravi Tomar, Maanak Gupta, Mathematical Modeling for Intelligent Systems, 2023
The data stored on the hard disk drive and within the file system is not lost because the storage is nonvolatile in nature. However, for volatile memory such as RAM, the data is lost as soon as the power is cut off. Once the power has been cut off for a period of time, the state of the data becomes completely unknown. This traditional approach is more commonly known as “pulling the plug” where the focus of analysis is on nonvolatile storage. This is now more commonly referred to as Dead Memory Acquisition. It refers to the powered-off or dead system, which is turned off and no data processing is taking place. It is performed by pulling the plug methodology to avoid any malicious process from running and potentially deleting evidence. There are fewer chances of data modification. It has practical, legal constraints and lacks standardized issues.
Spin manipulations in magnetic nanostructures
Published in Guo-ping Zhang, Georg Lefkidis, Mitsuko Murakami, Wolfgang Hübner, Tomas F. George, Introduction to Ultrafast Phenomena from Femtosecond Magnetism to high-harmonic Generation, 2020
Guo-ping Zhang, Georg Lefkidis, Mitsuko Murakami, Wolfgang Hübner, Tomas F. George
A computer memory is any physical device capable of storing the binary information. There are two types of computer memory: volatile and non-volatile. A volatile memory requires electric power to maintain stored information. For example, an operating system of your computer uses random-access memory (RAM) to process your commands. Most RAM available in the market uses semiconductor technology, i.e., it is electric-current dependent and therefore inevitably volatile. Each bit of information in semiconductor RAM is stored in a memory cell which consists of a tiny capacitor and a transistor called MOSFET (metal-oxide-semiconductor field-effect transistor). Billions of such memory cells are mounted on an integrated circuit (IC) or so-called microchip. A typical speed of RAM in a personal computer is a few GHz, which means that it can read or write a few billion bytes per second. Roughly speaking, it is said that the number of transistors in an IC doubles about every two years, which is called Moore’s Law.a (There is of course a limit as to what extent in time this law is valid.)
Introduction to Nonvolatile Organic Thin-Film Memory Devices
Published in Sam-Shajing Sun, Larry R. Dalton, Introduction to Organic Electronic and Optoelectronic Materials and Devices, 2016
Two kinds of volatile memory devices are widely used in a computer: SRAM (static random access memory) and DRAM (dynamic random access memory). An SRAM uses six metal oxide semiconductor field-effect transistors (MOSFETs) for a bit, whereas a DRAM uses one transistor in series with a capacitor for a bit. Figure 22.1 shows the structures of an SRAM and a DRAM. Information is retained in an SRAM as long as the power remains on, whereas frequent refreshment is needed to retain the information in a DRAM. However, volatile RAMs, like the DRAM, have the advantages of high speed and high density. The merits of high speed SRAM render them for use as cache memory in the microprocessor. Since a volatile memory device will lose its stored information when the external power is switched off, it cannot be used for long-term information storage.
Building memory devices from biocomposite electronic materials
Published in Science and Technology of Advanced Materials, 2020
Xuechao Xing, Meng Chen, Yue Gong, Ziyu Lv, Su-Ting Han, Ye Zhou
Since the birth of the first computer, the structure of the modern computer system is still based on the von Neumann principle, which is mainly composed of five parts: memory, arithmetic, controller, input equipment and output equipment. Among them, memory is used to store all kinds of data, which is an indispensable part of the computer. In addition, memory can be divided into volatile memory and non-volatile memory according to the data storing time in the memory. Volatile memory, where information is lost after a power outage, is mainly used to store programs that are used for a short period of time, such as dynamic random access memory (DRAM) [22–24]. The non-volatile memory can retain stored information after switching off the power, such as flash memory. With the popularization of mobile phones, digital cameras and other portable electronic devices, non-volatile memory is playing an increasingly important role in modern human’s daily life. With progresses of science and technology, the application of new non-volatile memory will bring a qualitative change to the performance of computers and people’s operating habits. The International Technology Roadmap for Semiconductor (ITRS), released in 2013, recommends RRAM after classifying and evaluating new types of memory currently being studied, and recommends acceleration of the commercialization.