Non-Volatile Memory Definition in Computer

Volatile memory has a lower storage capacity than non-volatile memory because it tends to be more expensive per unit and is not very cost-effective. A typical RAM chip won`t exceed a few GB of capacity, while super high-capacity RAM sells for hundreds or thousands of dollars. Common types of volatile memory include static random access memory (SRAM) and dynamic random access memory (DRAM). Manufacturers can add a battery to an ephemeral storage device so that it can permanently store data or controller code, but if the battery fails or is removed, the data is still lost. System manufacturers use different types of non-volatile memory chips for a variety of purposes. For example, an NVM type can store controller program code for devices such as hard disk drives (HDDs) and tape drives. Another type of NVM is commonly used for data storage in solid-state drives (SSDs), USB drives, and memory cards in digital cameras, mobile phones, and other devices. When you use your computer, you are always dealing with different types of data. And if you need to access any type of data at high speed right now, the volatile memory is ready. Ephemeral memory stores computer programs that are currently in temporary use by a device`s central processing unit (CPU). Once the device is turned off, the volatile memory is completely erased and then restarts when the device is turned back on. Manufacturers are working on additional types of non-volatile memory to reduce the cost per bit of data storage and program code, improve performance, increase endurance, and reduce power consumption.

Some users refuse to use NVM locations that match the first address (0x0000) and/or last address (0xffff) because they think they are statistically more likely to be corrupted. For example, SRAM is faster than DRAM and is great for high-speed caching. DRAM, the successor to SRAM, is cheaper to manufacture and requires less power than active SRAM. A common use case for DRAM is storing the main program code that a computer processor needs to run. A common use of non-volatile memory is to store instructions that are executed for the first time when the computer is turned on. These instructions are called startup code. When the computer is turned on for the first time, the RAM is “empty”, that is, it has random bits. The computer runs the startup code from non-volatile memory. The boot code initializes various registers in the processor and then scans the hard disk or CD drive for the rest of the operating system. It loads the main part of the operating system into RAM and starts executing the operating system code. Only at this point can the user request applications to run. NOR is a flash memory chip that is byte-addressable for reading but not writing.

NOR flash is different from NAND flash, which is pure memory where only large chunks of data (sectors) can be read or written. See Flash memory. Inside the recorder are a microchip and a non-volatile memory chip (similar to a CompactFlash card or USB flash drive). Depending on the amount of memory in the device, it can record between a few and dozens of pages with keystrokes. For example, 64 KB of memory stores about 32 pages. There is no need to install any software on the computer for the recorders to work, and they are compatible with a variety of PC operating systems. No battery or external power source is required. The device is powered by the computer.

Once the strokes are captured, the attacker removes the device and connects it to another PC. The data collected may be password protected; Once the correct password has been entered, it can be read in the editor or another text editor. After that, the data can be saved in a file and the memory of the device can be deleted. An example of a keylogger device is the KeyGhost (see In contrast, non-volatile memory such as HDDs and SSDs are slower than SRAM and DRAM, but cheaper to manufacture. Manufacturers often use NAND flash memory to continuously store data in enterprise systems and consumer devices. Storage devices such as Flash SSDs access data at the block level, while SRAM and DRAM support random access to byte-level data. Non-volatile electrically addressing semiconductor memories can be classified according to their writing mechanism. Mask ROMs are factory programmable only and are typically used for high-volume products that do not need to be updated after manufacturing. Programmable read-only memory can be changed after manufacturing, but requires a special programmer and usually cannot be programmed in the target system.

Programming is permanent and other changes require replacement of the device. Data is stored by physically changing (burning) the locations in the device. Non-volatile memory is increasingly competing with cache memory in terms of speed and cost (see static RAM). However, they are still more expensive than main memory (see dynamic RAM) and flash memory (see NAND flash). Non-volatile memory is memory that retains its values even if power is interrupted. Previous forms of non-volatile memory included various forms of read-only memory (ROMs). The data contained in these memory circuits were either applied directly to the circuit during the production process (ROM circuits) or programmed into the circuit by special devices (EPROMS, EEPROMS – erasable programmable read memories (electrically)). Current non-volatile memories use flash technology and can be written “in circuit”, i.e. during normal computer operation just like RAM.

However, writing to flash storage devices is much slower than writing to regular RAM and often has to be done in blocks instead of one byte each. In addition, the number of write/erase cycles is limited, currently limited to 100,000, before the cycle begins to deteriorate. Your computer needs both to work, but are they really that different? Memory that stores its contents without power. There are many types of non-fleeting memories. However, memory, which is sometimes mistakenly called non-volatile memory, is not one of them. Non-volatile memory refers to “byte addressable” memories that provide access to instructions and data at the byte level (see Addressable byte). See Memory vs Memory, Memory Types and Future Memory Chips. Phase change memory stores data in chalcogenide glass, which can reversibly change the phase between amorphous and crystalline states by heating and cooling the glass. The crystalline state has a low resistance and the amorphous phase has a high resistance, which makes it possible to turn currents on and off to represent the numerical states “1” and “0”. [8] [9] The NVM Host Controller Interface Working Group released the NVMe 1.0 specification on March 1, 2011. NVMe is designed to accelerate data transfer between host systems and SSDs over a computer`s PCIe bus.

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